業績情報

• Solvent-Induced Chirality Switching in the Enantioseparation of Hydroxycarboxylic Acids with a Quaternary Stereogenic Center
  Koichi Kodama; Yumi Kondo; Takuji Hirose
  ACS Omega, 巻：10, 号：12, 開始ページ：12129, 終了ページ：12134, 2025年03月, ［査読有り］, ［筆頭著者, 責任著者］
  American Chemical Society (ACS), 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1021/acsomega.4c10205
  DOI ID：10.1021/acsomega.4c10205, ISSN：2470-1343, eISSN：2470-1343
• Enantioseparation via Chiral Supramolecular Gels Comprising Ambidextrous Gelators Based on β‐Peptide‐type Primary Amines　　　　　　　　　　　　　　　
  Koichi Kodama; Masato Obata; Takuji Hirose
  ChemPlusChem, 巻：89, 号：8, 2024年03月, ［査読有り］, ［筆頭著者, 責任著者］
  Abstract
  
  While β‐peptides have been paid attention due to their diverse secondary structures, their application to the design of low‐molecular‐weight gelators (LMWGs) is less explored. In this work, chiral cyclic β‐amino acid‐based β‐peptides were developed as ambidextrous LMWGs, wherein multiple hydrogen bonds between the amide moieties led to high gelation ability. Their molecular assembly was elucidated using spectroscopies, microscopy, and X‐ray analysis. Further, the supramolecular gel was used as a platform for the enantioselective extraction of (S)‐naproxen from its racemate under optimized conditions. These findings have expanded the utility of β‐peptides and shown the potential of supramolecular gels as a distinct dynamic medium for enantiomer separation.
  Wiley, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1002/cplu.202400021
  DOI ID：10.1002/cplu.202400021, ISSN：2192-6506, eISSN：2192-6506, 共同研究・競争的資金等ID：49401295
• Enantiomer separation of 2‐halomandelic acids via diastereomeric salt formation with chiral N‐substituted 2‐amino‐2‐phenylethanols
  Koichi Kodama; Yumi Kondo; Kosei Katayama; Moeka Yanagisawa; Takuji Hirose
  Chirality, 巻：36, 号：2, 2023年11月, ［査読有り］, ［筆頭著者, 責任著者］
  Abstract
  
  Chiral N‐substituted secondary 1,2‐aminoalcohols have been developed for the enantioseparation of ortho‐halomandelic acids (o‐X‐MAs) via diastereomeric salt formation. Two structural isomers, N‐methyl‐2‐amino‐1,2‐diphenylethanol and N‐benzyl‐2‐amino‐2‐phenylethanol, showed high separation abilities for o‐X‐MAs (X = Cl, Br, I). The chiral recognition mechanism was elucidated by crystallographic analysis of the less‐soluble salts. The substituents on the nitrogen atom of the resolving agents and the inclusion of the crystallization solvent stabilized the salt and enhanced their separation ability.
  Wiley, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1002/chir.23630
  DOI ID：10.1002/chir.23630, ISSN：0899-0042, eISSN：1520-636X
• Thermoreversible helical fibers from photoreactive triphenylene-derived liquid crystals in liquid paraffin　　　　　　　　　　　　　　　
  Takuji Hirose; Yuka Kikuchi; Tomoaki Nakano; Tsukasa Ohno; Kengo Kawamura; Normazliana Binti Nazri; Atsuhiro Fujimori; Koichi Kodama; Mikio Yasutake
  Heliyon, 巻：9, 号：11, 開始ページ：e22037, 終了ページ：e22037, 2023年11月, ［査読有り］, ［責任著者］
  Elsevier BV, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.heliyon.2023.e22037
  DOI ID：10.1016/j.heliyon.2023.e22037, ISSN：2405-8440
• Chemical Storage of Ammonia through Dynamic Structural Transformation of a Hybrid Perovskite Compound
  Jyorthana Rajappa Muralidhar; Krishnachary Salikolimi; Kiyohiro Adachi; Daisuke Hashizume; Koichi Kodama; Takuji Hirose; Yoshihiro Ito; Masuki Kawamoto
  Journal of the American Chemical Society, 巻：145, 号：31, 開始ページ：16973, 終了ページ：16977, 2023年07月, ［査読有り］
  American Chemical Society (ACS), 研究論文（学術雑誌）
  DOI：https://doi.org/10.1021/jacs.3c04181
  DOI ID：10.1021/jacs.3c04181, ISSN：0002-7863, eISSN：1520-5126
• Development of Low‐Molecular‐Weight Organogelators from Cyclic β‐Amino Acid: Effect of Stereochemistry and their Application on Visual Chiral Recognition of Amines　　　　　　　　　　　　　　　
  Koichi Kodama; Masato Obata; Sho Sugimura; Hiroki Yuhara; Takuji Hirose
  Chemistry – A European Journal, 巻：29, 号：11, 2023年02月, ［査読有り］, ［筆頭著者, 責任著者］
  Wiley, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1002/chem.202202692
  DOI ID：10.1002/chem.202202692, ISSN：0947-6539, ORCID：138991333
• Enantioseparation of 3-Hydroxycarboxylic Acids via Diastereomeric Salt Formation by 2-Amino-1,2-diphenylethanol (ADPE) and Cinchonidine　　　　　　　　　　　　　　　
  Srinivas Chandrasekaran; Masaki Tambo; Yuta Yamazaki; Tatsuro Muramatsu; Yusuke Kanda; Takuji Hirose; Koichi Kodama
  Molecules, 巻：28, 号：1, 開始ページ：114, 終了ページ：114, 2022年12月, ［査読有り］, ［最終著者, 責任著者］
  Enantioseparation of 3-hydroxycarboxylic acids via diastereomeric salt formation was demonstrated using 2-amino-1,2-diphenylethanol (ADPE) and cinchonidine as the resolving agents. Racemic 3-hydroxy-4-phenylbutanoic acid (rac-1), 3-hydroxy-4-(4-chlorophenyl)butanoic acid (rac-2), and 3-hydroxy-5-phenylpentanoic acid (rac-3) were efficiently resolved using these resolving agents. Moreover, the successive crystallization of the less-soluble diastereomeric salt of 1 and cinchonidine using EtOH yielded pure (R)-1 · cinchonidine salt in a high yield. The crystal structures of less-soluble diastereomeric salts were elucidated and it was revealed that hydrogen bonding and CH/π interactions play an important role in reinforcing the structure of the less-soluble diastereomeric salts.
  {MDPI} {AG}, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.3390/molecules28010114
  DOI ID：10.3390/molecules28010114, ISSN：1420-3049, ORCID：138991330
• Chiral 1,3-aminosquaramides derived from cis-2-benzamidocyclohexanecarboxylic acid as organocatalysts for asymmetric Michael addition reactions　　　　　　　　　　　　　　　
  Koichi Kodama; Kazuhisa Maruyama; Takuji Hirose
  TETRAHEDRON, 巻：112, 開始ページ：132750, 終了ページ：132750, 2022年04月, ［査読有り］, ［筆頭著者, 責任著者］
  Herein, chiral 1,3-aminosquaramides derived from cis-2-benzamidocyclohexanecarboxylic acid, which is a chiral beta-amino acid derivative, were synthesized and applied as bifunctional organocatalysts for asymmetric Michael addition reaction of 1,3-dicarbonyl compounds to beta-nitrostyrenes. The catalyst structure and reaction conditions, such as solvent and temperature, were examined, and then, the optimized organocatalyst was successfully applied to the reaction of 1,3-diketones and 1,3-ketoesters with an enantioselectivity of up to 96%. Plausible transition state was proposed based on the results reported in previous reports and DFT calculations.
  PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.tet.2022.132750
  DOI ID：10.1016/j.tet.2022.132750, ISSN：0040-4020, eISSN：1464-5416, ORCID：138991304, Web of Science ID：WOS:000793348000002
• "Solvent-induced chirality switching" in the enantioseparation of chlorine-substituted tropic acids via diastereomeric salt formation by (1R,2S)-(-)-2-amino-1,2-diphenylethanol (ADPE)　　　　　　　　　　　　　　　
  Srinivas Chandrasekaran; Takuji Hirose; Koichi Kodama
  TETRAHEDRON, 巻：108, 開始ページ：132653, 終了ページ：132653, 2022年02月, ［査読有り］, ［最終著者, 責任著者］
  The optical resolution of chlorine-substituted tropic acids (TAs) by diastereomeric salt formation with (1R,2S)-(-)-2-amino-1,2-diphenylethanol ((-)-ADPE) has been demonstrated. Efficient solvent-induced chirality switching was observed in the case of racemic 2-chlorotropic acid (rac-2-Cl-TA). The recrystallization of the diastereomeric salts of rac-2-Cl-TA from branched alcohols such as i-PrOH and s-BuOH afforded (R)-2-Cl-TA, whereas (S)-2-Cl-TA was obtained from linear alcohols such as MeOH, EtOH, and n-PrOH. The chirality switching mechanism was elucidated from the crystal structures of the diastereomeric salts, which revealed that the incorporation of solvent in the (S)-2-Cl-TA salt crystals played a key role in chirality switching by reinforcing the supramolecular structure of the salt. However, no chirality switching was achieved for racemic 3-chlorotropic acid and 4-chlorotropic acid. The position of the chlorine substituent plays an important role in the solvent-induced chirality switching effect. (C) 2022 Elsevier Ltd. All rights reserved.
  PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.tet.2022.132653
  DOI ID：10.1016/j.tet.2022.132653, ISSN：0040-4020, eISSN：1464-5416, ORCID：138991295, Web of Science ID：WOS:000768763200008
• Efficient preparation of stereopure amphiphilic 1,2-amino alcohols by using preparative enantioselective HPLC　　　　　　　　　　　　　　　
  Hayato Kanai; Kuniyo Yamada; Koichi Kodama; Yasuhiro Ishida
  CHIRALITY, 巻：34, 号：2, 開始ページ：295, 終了ページ：305, 2022年02月, ［査読有り］
  Chiral amphiphiles are useful for controlling the structures and properties of supramolecular assemblies, but their stereocontrolled synthesis is generally difficult, because their long alkyl chains tend to bring unfavorable effects on the solubility, reactivity, and crystallinity of molecules. Typical examples are amphiphilic 1,2-amino alcohols (S)-1 and (1S,2S)-2 developed by our group, which were known to serve as chiral reaction media for controlling the stereochemistry of asymmetric photoreactions. We previously developed synthetic schemes for these 1,2-amino alcohols, but their synthetic efficiencies were unsatisfactory (13 steps with 2% overall yield for (S)-1; eight steps with 8% yield for (1S,2S)-2). As the main reason of such low efficiencies, the stereocontrolling methods we previously employed (diastereomer-salt crystallization for (S)-1; stereoselective reactions for (1S,2S)-2) were not ideal. Here, we report highly improved synthetic schemes for (S)-1 and (1S,2S)-2 based on the enantioselective high performance liquid chromatography (HPLC) separation of intermediates in preparative scales. Compared with the previous schemes, the new schemes are advantageous in fewer number of steps, higher overall yield, and lower risk of racemization (seven steps with 15% overall yield for (S)-1; seven steps with 26% overall yield for (1S,2S)-2).
  WILEY, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1002/chir.23395
  DOI ID：10.1002/chir.23395, ISSN：0899-0042, eISSN：1520-636X, ORCID：138991315, Web of Science ID：WOS:000719984500001
• Photocleavage behavior of a polythiophene derivative containing a coumarin unit　　　　　　　　　　　　　　　
  Jyorthana Rajappa Muralidhar; Koichi Kodama; Takuji Hirose; Yoshihiro Ito; Masuki Kawamoto
  POLYMER JOURNAL, 巻：54, 号：2, 開始ページ：191, 終了ページ：198, 2022年02月, ［査読有り］
  We synthesized a polythiophene derivative containing a photocleavable coumarin unit in the side chain. The resulting polymer contained 56% coumarin units with a number-average molecular weight of 17,000. When a film of the polythiophene derivative was irradiated at 313 nm, 54% of the coumarin groups were photocleaved. Fourier transform infrared spectroscopy revealed that the photocleaved side chains were transformed to carboxyl groups. Formation of the carboxyl group changed the nature of the surface of the polymer film from hydrophobic to hydrophilic. Furthermore, photocleavage of the coumarin unit changed the solubility of the polymer in organic solvents. Taking advantage of this solubility change, we photopatterned the polythiophene film using a photomask. In addition, the photocleaved polythiophene film showed a 10(4)-fold increase in electrical conductivity after chemical doping.
  SPRINGERNATURE, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1038/s41428-021-00574-z
  DOI ID：10.1038/s41428-021-00574-z, ISSN：0032-3896, eISSN：1349-0540, Web of Science ID：WOS:000713087800001
• Noncovalent Functionalization of Single-Walled Carbon Nanotubes with a Photocleavable Polythiophene Derivative　　　　　　　　　　　　　　　
  Jyorthana Rajappa Muralidhar; Koichi Kodama; Takuji Hirose; Yoshihiro Ito; Masuki Kawamoto
  NANOMATERIALS, 巻：12, 号：1, 2022年01月, ［査読有り］
  Single-walled carbon nanotubes (SWCNTs) have received extensive research attention owing to their extraordinary optical, electrical, and mechanical properties, which make them particularly attractive for application in optoelectronic devices. However, SWCNTs are insoluble in almost all solvents. Therefore, developing methods to solubilize SWCNTs is crucial for their use in solution-based processes. In this study, we developed a photocleavable polythiophene-derivative polymer dispersant for SWCNTs. The noncovalent surface functionalization of SWCNTs with a polymer allows their dispersal in tetrahydrofuran. The resultant solution-processed polymer/SWCNT composite film undergoes a hydrophobic-to-hydrophilic change in surface properties upon light irradiation (313 nm) because hydrophilic carboxyl groups are formed upon photocleavage of the hydrophobic solubilizing units in the polymer. Furthermore, the photocleaved composite film displays a 38-fold increase in electrical conductivity. This is due to the removal of the solubilizing unit, which is electrically insulating.
  MDPI, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.3390/nano12010052
  DOI ID：10.3390/nano12010052, eISSN：2079-4991, Web of Science ID：WOS:000751016200001
• Enantiomer Separation of Nitriles and Epoxides by Crystallization with Chiral Organic Salts: Chirality Switching Modulated by Achiral Acids　　　　　　　　　　　　　　　
  Koichi Kodama; Yuki Shimomura; Takuji Hirose
  CRYSTAL GROWTH & DESIGN, 巻：21, 号：11, 開始ページ：6552, 終了ページ：6557, 2021年11月, ［査読有り］, ［筆頭著者, 責任著者］
  Enantiomer separation of nitriles and epoxides by inclusion crystal formation with organic-salt type chiral hosts was achieved. The stereochemistry of the preferentially included nitrile could be switched only by changing the achiral carboxylic acid component. Crystallographic analysis of the inclusion crystals reveals that the hydrogen-bonding networks are controlled by the acidity of the phenol group of the acids, which results in chirality switching.
  AMER CHEMICAL SOC, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1021/acs.cgd.1c01003
  DOI ID：10.1021/acs.cgd.1c01003, ISSN：1528-7483, eISSN：1528-7505, ORCID：138991289, Web of Science ID：WOS:000715841000058
• Direct enantioseparation of axially chiral 1,1 '-biaryl-2,2 '-diols using amidine-based resolving agents　　　　　　　　　　　　　　　
  Koichi Kodama; Fusato Takase; Takuji Hirose
  RSC ADVANCES, 巻：11, 号：30, 開始ページ：18162, 終了ページ：18170, 2021年06月, ［査読有り］, ［筆頭著者, 責任著者］
  Amidine-based optically active resolving agents for enantiomer separation of axially chiral 1,1 '-biaryl-2,2 '-diols have been developed. A strongly basic amidine bearing no substituents on its nitrogen atoms enables the formation of their diastereomeric salts upon being mixed with weakly acidic phenol derivatives. Enantiopure 1,1 '-biaryl-2,2 '-diols can be obtained in high yields after only one crystallization of their salts with the chiral amidine derived from dehydroabietic acid. X-ray crystallography revealed that the amidine moiety forms a salt with the phenol group and additional intermolecular NH/pi interactions contribute to the efficient chiral recognition process.
  ROYAL SOC CHEMISTRY, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1039/d1ra03546k
  DOI ID：10.1039/d1ra03546k, ISSN：2046-2069, eISSN：2046-2069, ORCID：138991281, Web of Science ID：WOS:000654041100003
• Characterization and enantiomer separation of indene-derived hexacyclic hydrocarbon and its application as a chiral source　　　　　　　　　　　　　　　
  Koichi Kodama; Shohei Yamaguchi; Shigetaka Hayano; Takashi Houkawa; Yoshinori Kitahara; Hiroaki Shitara; Takuji Hirose
  TETRAHEDRON, 巻：87, 開始ページ：132082, 終了ページ：132082, 2021年05月, ［査読有り］, ［筆頭著者, 責任著者］
  A hexacyclic chiral aromatic hydrocarbon (1), obtained by the reaction between indene and cyclopentadiene, has been characterized, and its enantioseparation has been achieved by the combination of stereoselective complexation with beta-cyclodextrin and recrystallization. This method has been applied in the large-scale production of both pure enantiomers of 1. Enantiopure 1 and its derivatives have been used as chiral dopants in nematic liquid crystals. (C) 2021 Elsevier Ltd. All rights reserved.
  PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.tet.2021.132082
  DOI ID：10.1016/j.tet.2021.132082, ISSN：0040-4020, eISSN：1464-5416, ORCID：138991276, Web of Science ID：WOS:000645466300002
• Chirality switching in the enantioseparation of 2-hydroxy-4-phenylbutyric acid: Role of solvents in selective crystallization of the diastereomeric salt　　　　　　　　　　　　　　　
  Koichi Kodama; Meng Yi; Hiroaki Shitara; Takuji Hirose
  TETRAHEDRON LETTERS, 巻：61, 号：16, 開始ページ：151773, 終了ページ：151773, 2020年04月, ［査読有り］, ［筆頭著者, 責任著者］
  Chirality switching was induced by solvents in the enantioseparation of 2-hydroxy-4-phenylbutyric acid (HPBA) via diastereomeric salt formation with an enantiopure aminoalcohol. The (S)-salt was crystallized from butanol solutions and the (R)-salt was obtained from aqueous solutions. It was found from crystallographic analysis of the salts that solvent inclusion changed the solubility of both salts. In particular, the (R)-salt afforded multiple pseudo-polymorphic hydrated crystals. Successive crystallization from two different solvents efficiently afforded both pure diastereomeric salts. (C) 2020 Elsevier Ltd. All rights reserved.
  PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.tetlet.2020.151773
  DOI ID：10.1016/j.tetlet.2020.151773, ISSN：0040-4039, ORCID：138991227, Web of Science ID：WOS:000527104000005
• Efficient Pyrazole Moiety-Containing Ligands for Cu-Catalyzed O-Arylation of Phenols　　　　　　　　　　　　　　　
  Yingying Zhao; Xiangyong Wang; Ryo Kaneyama; Koichi Kodama; Takuji Hirose
  CHEMISTRYSELECT, 巻：5, 号：14, 開始ページ：4152, 終了ページ：4159, 2020年04月, ［査読有り］
  Seven pyrazole- or pyridine-containing N-2- and N-3-ligalitnds (L1-L7) were developed for the ligand-assisted CuI-catalyzed coupling reactions of aryl halides with phenols. The structural and electronic effects were studied for various combinations of pyridine and/or imine nitrogen binding sites in the ligands. Screening their abilities showed most of them to be better than 4,4'-dimethoxybipyridine (L8). Among them, 2-(1-pyrazolyl)pyridine (L1) featuring two types of binding sites gave the best results, with yields of up to 95% at 100 degrees C at a catalyst loading of 10 mol% (CuI/L in 1 : 1 ratio). Free radical scavengers, 2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) (1.0 eq.) and cumene (1.0 eq.), lowered the yields by more than half, but the reaction was not completely quenched even when 3.0 eq. of TEMPO was used. A non-radical and a radical mechanisms, are proposed for the L1-promoted coupling reaction, well explained the experiments results. In addition, the structure of the catalyst species were elucidated through single crystal XRD and DFT (density functional theory) calculations.
  WILEY-V C H VERLAG GMBH, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1002/slct.201903359
  DOI ID：10.1002/slct.201903359, ISSN：2365-6549, ORCID：138991270, Web of Science ID：WOS:000529295500004
• Solvent-Induced Chirality Switching in the Enantioseparation of Halogen-Substituted Mandelic Acids: Structural Effects on Molecular Packing　　　　　　　　　　　　　　　
  Koichi Kodama; Kozue Kawasaki; Meng Yi; Kaguya Tsukarnoto; Hiroaki Shitara; Takuji Hirose
  CRYSTAL GROWTH & DESIGN, 巻：19, 号：12, 開始ページ：7153, 終了ページ：7159, 2019年12月, ［査読有り］, ［筆頭著者, 責任著者］
  The solvent effect on the enantioseparation of halogen-substituted mandelic acid derivatives via diastereomerit salt formation has been investigated. The diastereomeric salts of para-halogen-substituted mandelic acid derivatives (p-X-MA) were obtained with high efficiency. In addition, both diastereomeric salts of p-F-MA were successfully obtained by controlling the concentration of the acetone solution. Efficient solvent-induced chirality switching was generally observed for meta-halogen-substituted mandelic acid derivatives (m-X-MA). Water, aprotic solvents, and short-chain alcohols such as i-PrOH gave the (S)-salt, whereas the (R)-salt is preferentially formed from long-chain alcohols such as n-BuOH and s-BuOH. Crystallographic analysis of the salts showed that the inclusion of the alcohol solvent in the diastereomeric salts changed the hydrogen-bonding network and molecular packing. The molecular packing was dependent on the size of the halogen substituents and the solvent used. Finally, this technique has been successfully applied to the preparation of both pure enantiomers of m-Cl-MA.
  AMER CHEMICAL SOC, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1021/acs.cgd.9b01015
  DOI ID：10.1021/acs.cgd.9b01015, ISSN：1528-7483, eISSN：1528-7505, ORCID：69675472, Web of Science ID：WOS:000501621100038
• Synthesis and evaluation of chiral beta-amino acid-based low-molecular-weight organogelators possessing a methyl/trifluoromethyl side chain　　　　　　　　　　　　　　　
  Kodama Koichi; Kawamata Ryuta; Hirose Takuji
  New Journal of Chemistry, 巻：43, 号：7, 開始ページ：2882, 終了ページ：2887, 2019年, ［査読有り］, ［筆頭著者, 責任著者］
  研究論文（学術雑誌）
  DOI：https://doi.org/10.1039/c8nj05668d
  DOI ID：10.1039/c8nj05668d, ORCID：55398499, Web of Science ID：WOS:000459944500046
• Polymeric fibers and microporous films by photo-crosslinking of triphenylene-derived liquid crystals　　　　　　　　　　　　　　　
  Hirose Takuji; Xu Zhe; Kikuchi Yuka; Fukushima Masahito; Kawamura Kengo; Kaguchi Yosuke; Kodama Koichi; Yasutake Mikio
  Journal of Polymer Science Part A-Polymer Chemistry, 巻：57, 号：5, 開始ページ：605, 終了ページ：612, 2019年, ［査読有り］
  Two series of photoreactive discotic liquid crystals consisting of a triphenylene core and six cinnamate units with one (TPC1(n)) or two (TPC2(n)) n-alkoxy groups (CnH2n+1O; n = 10-14), respectively, as peripheral groups are synthesized. Both of them are polymerized into fibers up to 2 mm long by UV irradiation in liquid paraffin in the columnar LC temperature ranges. The fiber structures seem to be preconstructed in liquid paraffin. In addition, TPC2(n) are shown to form microporous films up to 15 mu m in diameter by simply casting the solutions of some solvents followed by drying for several minutes in air at room temperature. Photoirradiation of the films in the LC temperature range converts them to polymeric ones while preserving the microporous and hexagonally ordered structure. From comparison with TPC1(n) and the hydrogenated derivative of TPC2(12), the porous film-forming property is suggested to result from the combination of the double bond of the cinnamoyl group and the two long alkoxy chains on the phenyl ring. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 605-612
  WILEY, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1002/pola.29299
  DOI ID：10.1002/pola.29299, ISSN：0887-624X, eISSN：1099-0518, ORCID：55398498, Web of Science ID：WOS:000456602400004
• Photocatalytic CO2 Reduction by Trigonal-Bipyramidal Cobalt(II) Polypyridyl Complexes: The Nature of Cobalt(I) and Cobalt(0) Complexes upon Their Reactions with CO2, CO, or Proton　　　　　　　　　　　　　　　
  Tomoe Shimoda; Takeshi Morishima; Koichi Kodama; Takuji Hirose; Dmitry E. Polyansky; Gerald F. Manbeck; James T. Muckerman; Etsuko Fujita
  Inorganic Chemistry, 巻：57, 号：9, 開始ページ：5486, 終了ページ：5498, 2018年05月, ［査読有り］
  The cobalt complexes CoIIL1(PF6)2 (1
  L1 = 2,6-bis[2-(2,2′-bipyridin-6′-yl)ethyl]pyridine) and CoIIL2(PF6)2 (2
  L2 = 2,6-bis[2-(4-methoxy-2,2′-bipyridin-6′-yl)ethyl]pyridine) were synthesized and used for photocatalytic CO2 reduction in acetonitrile. X-ray structures of complexes 1 and 2 reveal distorted trigonal-bipyramidal geometries with all nitrogen atoms of the ligand coordinated to the Co(II) center, in contrast to the common six-coordinate cobalt complexes with pentadentate polypyridine ligands, where a monodentate solvent completes the coordination sphere. Under electrochemical conditions, the catalytic current for CO2 reduction was observed near the Co(I/0) redox couple for both complexes 1 and 2 at E1/2 = -1.77 and -1.85 V versus Ag/AgNO3 (or -1.86 and -1.94 V vs Fc+/0), respectively. Under photochemical conditions with 2 as the catalyst, [Ru(bpy)3]2+ as a photosensitizer, tri-p-tolylamine (TTA) as a reversible quencher, and triethylamine (TEA) as a sacrificial electron donor, CO and H2 were produced under visible-light irradiation, despite the endergonic reduction of Co(I) to Co(0) by the photogenerated [Ru(bpy)3]+. However, bulk electrolysis in a wet CH3CN solution resulted in the generation of formate as the major product, indicating the facile production of Co(0) and [Co-H]n+ (n = 1 and 0) under electrochemical conditions. The one-electron-reduced complex 2 reacts with CO to produce [Co0L2(CO)] with νCO = 1894 cm-1 together with [CoIIL2]2+ through a disproportionation reaction in acetonitrile, based on the spectroscopic and electrochemical data. Electrochemistry and time-resolved UV-vis spectroscopy indicate a slow CO binding rate with the [CoIL2]+ species, consistent with density functional theory calculations with CoL1 complexes, which predict a large structural change from trigonal-bipyramidal to distorted tetragonal geometry. The reduction of CO2 is much slower than the photochemical formation of [Ru(bpy)3]+ because of the large structural changes, spin flipping in the cobalt catalytic intermediates, and an uphill reaction for the reduction to Co(0) by the photoproduced [Ru(bpy)3]+.
  American Chemical Society, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1021/acs.inorgchem.8b00433
  DOI ID：10.1021/acs.inorgchem.8b00433, ISSN：1520-510X, ORCID：55398503, SCOPUS ID：85046633106, Web of Science ID：WOS:000431833500080
• Enantioseparation of Sulfoxides and Nitriles by Inclusion Crystallization with Chiral Organic Salts Based on l-Phenylalanine　　　　　　　　　　　　　　　
  Koichi Kodama; Hayato Kanai; Yuki Shimomura; Takuji Hirose
  European Journal of Organic Chemistry, 巻：2018, 号：14, 開始ページ：1726, 終了ページ：1729, 2018年04月, ［査読有り］
  Enantioselective inclusion of aromatic sulfoxides and nitriles was achieved in a host framework created by organic salts comprising achiral benzoic acids and a chiral primary amine (1a) derived from l-phenylalanine. Tuning of the combined achiral acid component successfully changed the chiral recognition ability of the organic salts. The guest molecules were hydrogen-bonded to form three-component inclusion crystals, and the enantiomers of nitriles and sulfoxides were separated with high selectivity up to 92 and 98 % ee. As far as we know, this is the first example of the enantioseparation of non-functionalized aromatic nitriles.
  Wiley-VCH Verlag, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1002/ejoc.201800003
  DOI ID：10.1002/ejoc.201800003, ISSN：1099-0690, ORCID：55398501, SCOPUS ID：85045659514, Web of Science ID：WOS:000430286900013
• Organocatalyst system for disubstituted carbonates from cycloaddition between CO2 and internal epoxides　　　　　　　　　　　　　　　
  Takuji Hirose; Shujie Qu; Koichi Kodama; Xiangyong Wang
  Journal of CO2 Utilization, 巻：24, 開始ページ：261, 終了ページ：265, 2018年03月, ［査読有り］
  An organocatalyst system, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and nBu4NCl, was developed for the conversion of CO2 and internal epoxides to the corresponding disubstituted cyclic carbonates under rather mild conditions (1–4 atm of CO2 and 100–120 °C). Catalyst screening revealed that small Cl− opens epoxide rings more effectively than larger Br− and I− do when used as the counter anion of nBu4N+, suggesting that the steric hindrance of the internal epoxides is a factor. A practical and economical alternative system, DBU and nBuCl, is also presented.
  Elsevier Ltd, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.jcou.2018.01.016
  DOI ID：10.1016/j.jcou.2018.01.016, ISSN：2212-9820, eISSN：2212-9839, ORCID：55398502, SCOPUS ID：85041480514, Web of Science ID：WOS:000428234500030
• Copper-Catalyzed Coupling Reactions of Aryl Halides and Phenols by 4,4 '-Dimethoxy-2,2 '-bipyridine and 4,7-Dimethoxy-1,10-phenanthroline　　　　　　　　　　　　　　　
  Zhao Yingying; Wang Xiangyong; Kodama Koichi; Hirose Takuji
  Chemistryselect, 巻：3, 号：44, 開始ページ：12620, 終了ページ：12624, 2018年, ［査読有り］
  Several Cu(I) complexes of 2,2'-bipyridines were studied for the catalytic coupling of aryl iodides and phenols and 4,4'-dimethoxy-2,2'-bipyridine was shown to be an effective ligand of CuI in 1:2 (CuI:ligand) ratio for the synthesis of a wide range of diaryl ethers (up to 97% yield) using K3PO4 as base in DMF at 100 degrees C. The catalysis was highly dependent on the reaction temperature and was successfully applied in the coupling with more attractive and challenging substrates, aryl bromides, at 140 degrees C in good-to-excellent yields (78-95%). Moreover, the heteroaromatic effect for the reaction was studied and gave a comparable result with phenyl group (up to 95% yield). Significantly, a structurally related N,N-bidentate ligand, 4,7-dimethoxy-1,10-phenanthroline, exhibited better performance for less-reactive combinations of aryl halides and phenols.
  WILEY-V C H VERLAG GMBH, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1002/slct.201802278
  DOI ID：10.1002/slct.201802278, ISSN：2365-6549, ORCID：55398500, Web of Science ID：WOS:000452173000030
• Poly(4-vinylphenol)/tetra-n-butylammonium iodide: Efficient organocatalytic system for synthesis of cyclic carbonates from CO2 and epoxides　　　　　　　　　　　　　　　
  Xiangyong Wang; Yingying Zhao; Koichi Kodama; Takuji Hirose
  JOURNAL OF APPLIED POLYMER SCIENCE, 巻：134, 号：33, 2017年09月, ［査読有り］
  An efficient polymer-based catalytic system of poly(4-vinylphenol) and tetra-n-butylammonium iodide was developed for the synthesis of cyclic carbonates from epoxides and CO2. Owing to the synergistic effects of hydroxyl groups and iodide anions, this commercially available and metal-free system was highly active for the reaction of various terminal epoxides under environmentally benign conditions, at 25 to 60 degrees C and atmospheric pressure of CO2, without the use of any organic solvents. The catalyst system can be easily separated by adding ether, and its ability was recovered by treating it with 40% CH3CO2H aq. The recyclability was investigated in detail for three substrates, epichlorohydrin, 1,2-epoxyhexane, and styrene oxide, using H-1 nuclear magnetic resonance analysis. (C) 2017 Wiley Periodicals, Inc.
  WILEY, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1002/app.45189
  DOI ID：10.1002/app.45189, ISSN：0021-8995, eISSN：1097-4628, ORCID：55398505, Web of Science ID：WOS:000402201600020
• Solvent-induced chirality switching in the enantioseparation of regioisomeric hydroxyphenylpropionic acids via diastereomeric salt formation with (1R,2S)-2-amino-1,2-diphenylethanol`　　　　　　　　　　　　　　　
  Koichi Kodama; Jun Nagata; Nobuhiro Kurozumi; Hiroaki Shitara; Takuji Hirose
  TETRAHEDRON-ASYMMETRY, 巻：28, 号：3, 開始ページ：460, 終了ページ：466, 2017年03月, ［査読有り］
  The enantioseparation of three hydroxyphenylpropionic acid isomers via diastereomeric salt formation with (1R,2S)-2-amino-1,2-diphenylethanol has been demonstrated. The racemates of all three acid isomers were successfully separated with high efficiency (0.56-0.84) after single crystallization. For 2-hydroxy-3-phenylpropionic acid 4, the configuration of the less-soluble salt was controlled by the crystallization solvent: the (R)-4 salt was crystallized from water, while 2-propanol afforded the (S)-4 salt. The chiral recognition mechanism of the three acids was discussed based on the crystal structures of the diastereomeric salts. (C) 2017 Elsevier Ltd. All rights reserved.
  PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.tetasy.2017.02.011
  DOI ID：10.1016/j.tetasy.2017.02.011, ISSN：0957-4166, ORCID：55398506, Web of Science ID：WOS:000398332600011
• Efficient and practical organocatalytic system for the synthesis of cyclic carbonates from carbon dioxide and epoxides: 3-hydroxypyridine/tetra-n-butylammonium iodide　　　　　　　　　　　　　　　
  Xiangyong Wang; Lin Wang; Yingying Zhao; Koichi Kodama; Takuji Hirose
  TETRAHEDRON, 巻：73, 号：8, 開始ページ：1190, 終了ページ：1195, 2017年02月, ［査読有り］
  An efficient and practical organocatalytic system comprising 3-hydroxypyridine and tetra-n-butylammonium iodide was developed for the synthesis of cyclic carbonates from carbon dioxide and epoxides under mild conditions (1 atm CO2, 25-60 degrees C) without organic solvent. By comparing with related hydroxypyridine derivatives, the effects of the hydroxyl group, the acidity and the steric factor, were discussed. Study on the mixtures of CO2 and N-2 in various ratios indicated that the yield depends on CO2 content, due to the solubility of CO2 in the reaction mixture. The system was also shown not to be deteorated by the presence of H2O, air or O-2. (C) 2017 Elsevier Ltd. All rights reserved.
  PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.tet.2017.01.018
  DOI ID：10.1016/j.tet.2017.01.018, ISSN：0040-4020, ORCID：55398504, Web of Science ID：WOS:000394194400015
• Formation of Ternary Inclusion Crystal and Enantioseparation of Alkyl Aryl Sulfoxides by the Salt of Urea-Modified L-Phenylalanine and an Achiral Amine　　　　　　　　　　　　　　　
  Koichi Kodama; Rina Morita; Takuji Hirose
  CRYSTAL GROWTH & DESIGN, 巻：16, 号：9, 開始ページ：5206, 終了ページ：5213, 2016年09月, ［査読有り］
  Chiral supramolecular hosts comprising urea-modified L-phenylalanines and achiral primary amines were developed, which facilitated enantioselective inclusion of alkyl aryl sulfoxides (3) up to 89% ee owing to the formation of ternary inclusion crystals. From the structural optimization of the components, the combination of N-(phenylcarbamoyl)-L-phenylalanine (1a) and benzhydrylamine (2e) showed the best inclusion ability among the considered supramolecular hosts. The type of the hydrogen-bonding network of ammonium-carboxylate salts 1a center dot 2 was dependent on the steric bulk of combined primary amine 2. The rigid phenylurea moiety of 1a and moderate steric bulk of 2e played an important role in their high inclusion ability. Host 1a center dot 2e afforded two ternary polymorphic inclusion crystals with the inclusion of acetonitrile. Furthermore, the crystal structures of 1a center dot 2e center dot 3 revealed that the inclusion of 3 was assisted by hydrogen bonding to the host and that stereoselectivity reversal occurred for larger sulfoxides, which was attributed to packing variations of one-dimensional hydrogen-bonding networks.
  AMER CHEMICAL SOC, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1021/acs.cgd.6b00768
  DOI ID：10.1021/acs.cgd.6b00768, ISSN：1528-7483, eISSN：1528-7505, ORCID：27611389, Web of Science ID：WOS:000382902400052
• Direct enantioseparation of diarylmethylamines with an ortho-hydroxy group via diastereomeric salt formation and their application to the enantioselective addition reaction of diethylzinc　　　　　　　　　　　　　　　
  Koichi Kodama; Naoki Hayashi; Yasuhiko Yoshida; Takuji Hirose
  TETRAHEDRON, 巻：72, 号：10, 開始ページ：1387, 終了ページ：1394, 2016年03月, ［査読有り］
  Two chiral diarylmethylamines with a phenolic hydroxy group at their ortho positions (1c and Id) were synthesized, and their direct enantioseparation via diastereomeric salt formation was investigated. Crystallographic analyses of the diastereomeric salts involving 1c were conducted: water molecules incorporated in the space played an important role in chiral recognition. Enantiopure 1 were applied for the enantioselective addition of diethylzinc to benzaldehyde. Ligand (R)-1d afforded the product in very high yield (96%) and enantiopurity (92% ee). Not only the phenyl group on the stereogenic center of (R) 1d but also its bulky tert-butyl group is important for chiral induction. (C) 2016 Elsevier Ltd. All rights reserved.
  PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.tet.2016.01.034
  DOI ID：10.1016/j.tet.2016.01.034, ISSN：0040-4020, ORCID：27611387, Web of Science ID：WOS:000370906600015
• Cationic Polymerization of Vinyl Ethers and p-Methoxystyrene by a Benign Initiating System: Silver Salt/Arylmethyl Halide/Dialkyl Sulfide　　　　　　　　　　　　　　　
  Li Lin; Guangyou Zhang; Koichi Kodama; Hiroaki Shitara; Takuji Hirose
  JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, 巻：54, 号：6, 開始ページ：861, 終了ページ：870, 2016年03月, ［査読有り］
  Three vinyl ethers (VEs: isobutyl vinyl ether, ethyl vinyl ether, and isopropyl vinyl ether) and an active styrene derivative, p-methoxystyrene (pMOS), were employed for cationic polymerization using a benign initiating system, AgClO4/Ph2CHBr/dialkyl sulfide. Choosing a sulfide with suitable nucleophilicity was important for achieving controlled polymerization. Additionally, selecting an appropriate reaction temperature based on monomer reactivity was also crucial for suppressing side reactions. Highly controlled polymerizations of VEs and pMOS were further confirmed by proton nuclear magnetic resonance (H-1 NMR) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). In addition, the coordination of the arylmethyl cation to the added base obviously influenced the initiation, as demonstrated by H-1 NMR analysis. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 861-870
  WILEY-BLACKWELL, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1002/pola.27925
  DOI ID：10.1002/pola.27925, ISSN：0887-624X, eISSN：1099-0518, ORCID：27611385, Web of Science ID：WOS:000370005300014
• Economical synthesis of cyclic carbonates from carbon dioxide and halohydrins using K2CO3　　　　　　　　　　　　　　　
  Takuji Hirose; Shinsuke Shimizu; Shujie Qu; Hiroaki Shitara; Koichi Kodama; Lin Wang
  RSC ADVANCES, 巻：6, 号：73, 開始ページ：69040, 終了ページ：69044, 2016年, ［査読有り］
  A highly simple, economical, and selective synthesis of five-membered cyclic carbonates was achieved by the reaction of CO2 with 1,2-halohydrins in the presence of K2CO3. This method allows the efficient preparation of cyclic carbonates (72-95% yields for monosubstituted cyclic carbonates and 43% for 1,1- and 1,2-disubstituted cyclic carbonates) under mild reaction conditions, atmospheric pressure of CO2 at 30 degrees C, and not only in dry DMF, but also in commercial "anhydrous" DMF. The reaction mechanism was elucidated using the SEM and XRD data of the by-products, KHCO3 and KBr.
  ROYAL SOC CHEMISTRY, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1039/c6ra13008a
  DOI ID：10.1039/c6ra13008a, ISSN：2046-2069, ORCID：27611388, Web of Science ID：WOS:000381512600055
• DBU/benzyl bromide: an efficient catalytic system for the chemical fixation of CO2 into cyclic carbonates under metal- and solvent-free conditions　　　　　　　　　　　　　　　
  Lin Wang; Koichi Kodama; Takuji Hirose
  CATALYSIS SCIENCE & TECHNOLOGY, 巻：6, 号：11, 開始ページ：3872, 終了ページ：3877, 2016年, ［査読有り］
  A simple, mild, and inexpensive catalytic system consisting of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) and benzyl bromide was developed for the cycloaddition of epoxides with ambient CO2 under metal-free and solvent-free conditions. Moreover, a wide range of epoxides was converted to the corresponding cyclic carbonates with good to excellent yields (81-95%).
  ROYAL SOC CHEMISTRY, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1039/c5cy01892g
  DOI ID：10.1039/c5cy01892g, ISSN：2044-4753, eISSN：2044-4761, ORCID：27611386, Web of Science ID：WOS:000378276100024
• An efficient metal- and solvent-free organocatalytic system for chemical fixation of CO2 into cyclic carbonates under mild conditions　　　　　　　　　　　　　　　
  Lin Wang; Guangyou Zhang; Koichi Kodamaa; Takuji Hirose
  GREEN CHEMISTRY, 巻：18, 号：5, 開始ページ：1229, 終了ページ：1233, 2016年, ［査読有り］
  An efficient, metal- and solvent-free catalytic system was developed for the conversion of CO2 and epoxides to the corresponding cyclic carbonates under mild conditions (T = 25-45 degrees C, 1 atm CO2) in high-to-excellent yields. The catalyst could be easily recycled, providing a more sustainable process for the chemical fixation of CO2.
  ROYAL SOC CHEMISTRY, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1039/c5gc02697k
  DOI ID：10.1039/c5gc02697k, ISSN：1463-9262, eISSN：1463-9270, ORCID：27611384, Web of Science ID：WOS:000371608100008
• A systematic study on ternary inclusion crystals consisting of dianilines and three positional isomers of ditoluoyl-L-tartaric acid　　　　　　　　　　　　　　　
  Koichi Kodama; Yuya Morita; Eriko Sekine; Takuji Hirose
  CRYSTENGCOMM, 巻：18, 号：1, 開始ページ：123, 終了ページ：129, 2016年, ［査読有り］
  The structure and inclusion ability of eight types of salts prepared from a combination of four tartaric acid derivatives (dibenzoyl-and three positional isomers of ditoluoyl-L-tartaric acid) and two V-shaped dianilines were investigated. They afforded 1 : 1 or 2 : 1 stoichiometric salts and the hydrogen-bonding networks changed from three-dimensional to two-and one-dimensional networks as the distance between the methyl and carboxyl groups on the tartaric acid increased. When the methylene group of dianiline was changed to an oxygen atom, the molecular structure became thinner, forming a different hydrogen-bonding network. Despite such diverse hydrogen-bonding networks, all the salts incorporated water and/or 2-butanol molecules in their structure, affording ternary or quaternary inclusion crystals.
  ROYAL SOC CHEMISTRY, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1039/c5ce01769f
  DOI ID：10.1039/c5ce01769f, ISSN：1466-8033, ORCID：27611383, Web of Science ID：WOS:000366840100013
• A benign initiating system for cationic polymerization of isobutyl vinyl ether: Silver salt/aryl(alkyl) halide/lewis base　　　　　　　　　　　　　　　
  Li Lin; Guangyou Zhang; Koichi Kodama; Mikio Yasutake; Takuji Hirose
  JOURNAL OF POLYMER SCIENCE PART A-POLYMER CHEMISTRY, 巻：53, 号：17, 開始ページ：2050, 終了ページ：2058, 2015年09月, ［査読有り］
  Aryl(alkyl) halides and silver salts were studied as environmentally benign initiating systems for cationic polymerization of isobutyl vinyl ether (IBVE). The reactivity of the benzyl cations could be effectively controlled by using dimethyl sulfide (Me2S) as an additive, which was shown to be an effective Lewis base (LB), and diethyl ether as a reaction solvent. Detailed study of various benzyl cations and the order of addition of the reagents revealed that the reaction was controlled by the electronic and steric features of aryl(alkyl) halides, LBs, and IBVE, and a plausible reaction mechanism was presented. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 2050-2058
  WILEY-BLACKWELL, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1002/pola.27656
  DOI ID：10.1002/pola.27656, ISSN：0887-624X, eISSN：1099-0518, ORCID：27611390, Web of Science ID：WOS:000358512900011
• Trialkylsilylethynyl-substituted triphenylenes and hexabenzocoronenes: highly soluble liquid crystalline materials and their hole transport abilities　　　　　　　　　　　　　　　
  Takuji Hirose; Yutaro Miyazaki; Mizuki Watabe; Sho Akimoto; Tatsuya Tachikawa; Koichi Kodama; Mikio Yasutake
  TETRAHEDRON, 巻：71, 号：29, 開始ページ：4714, 終了ページ：4721, 2015年07月, ［査読有り］
  Four triphenylene (TP) and four hexa-peri-hexabenzocoronene (HBC) derivatives with trialkylsilylethynyl groups were prepared and characterized by differential scanning calorimetry, polarizing optical microscopy, and X-ray diffraction measurements. All compounds were highly soluble in less-polar organic solvents and exhibited a columnar phase, Col(h) or Col(r) for the TPs, and Col(h) for the HBCs. The hole transport ability in the HBCs' columnar phase, 0.4-1.5x10(-3) cm(2) V-1 s(-1) at 40-180 degrees C, and its temperature dependence were determined by the time-of-flight method using a solution technique. (C) 2015 Elsevier Ltd. All rights reserved.
  PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.tet.2015.05.071
  DOI ID：10.1016/j.tet.2015.05.071, ISSN：0040-4020, ORCID：27611391, Web of Science ID：WOS:000357348100003
• Solvent-induced dual chirality switching in the optical resolution of tropic acid via diastereomeric salt formation with (1R,2S)-2-amino-1,2-diphenylethanol　　　　　　　　　　　　　　　
  Koichi Kodama; Nobuhiro Kurozumi; Hiroaki Shitara; Takuji Hirose
  TETRAHEDRON, 巻：70, 号：43, 開始ページ：7923, 終了ページ：7928, 2014年10月, ［査読有り］
  Solvent-induced chirality switching in the optical resolution of racemic tropic acid (TA) with (1R,2S)-2-amino-1,2-diphenylethanol has been demonstrated. Recrystallization of the diastereomeric salt mixture from i-PrOH or EtOH afforded the (S)-TA salt, while the (R)-TA salt was deposited from 1,4-dioxane and water-enriched alcohol solutions. Dual chirality switching was achieved by using two different types of solvents. The X-ray crystal structures of both diastereomeric salts showed that incorporation of the crystallization solvent played a crucial role in stabilizing each diastereomeric salt crystal. The mechanism of chirality switching has been discussed on the basis of the relative stability of the salt, as deduced from their structures. (C) 2014 Elsevier Ltd. All rights reserved.
  PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.tet.2014.08.053
  DOI ID：10.1016/j.tet.2014.08.053, ISSN：0040-4020, ORCID：27611395, Web of Science ID：WOS:000343344500013
• Effect of alkoxy terminal chain length on mesomorphism of 1,6-disubstituted pyrenebased hexacatenar liquid crystals: columnar phase control　　　　　　　　　　　　　　　
  Takuji Hirose; Hiroaki Takai; Mizuki Watabe; Hiroyuki Minamikawa; Tatsuya Tachikawa; Koichi Kodama; Mikio Yasutake
  TETRAHEDRON, 巻：70, 号：34, 開始ページ：5100, 終了ページ：5108, 2014年08月, ［査読有り］
  Synthesis and mesophase-transition behaviors of six 1,6-disubstituted pyrene-based hexacatenar liquid crystals 1(n) (n=8-18) are reported here. They were synthesized by the Sonogashira coupling between 1,6-diethynylpyrene and 2-bromothiophene bearing a trialkoxybenzoyl group. The phase-transition behavior was studied by differential scanning calorimetry and polarized optical microscopy; a few mesophase progressions, I-Col/I-X-Col and Col-Sm, were observed, where X was an optically isotropic but un-identified phase. The structures of Col(r), Col(h), and Sm phases were analyzed by the X-ray crystallography, and the effect of the terminal alkoxy chain length on the mesomorphism was evaluated. (C) 2014 Elsevier Ltd. All rights reserved.
  PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.tet.2014.05.111
  DOI ID：10.1016/j.tet.2014.05.111, ISSN：0040-4020, ORCID：27611394, Web of Science ID：WOS:000339035200011
• Chirality Switching in Optical Resolution of Mandelic Acid in C1-C4 Alcohols: Elucidation of Solvent Effects Based on X-ray Crystal Structures of Diastereomeric Salts　　　　　　　　　　　　　　　
  Koichi Kodama; Hiroaki Shitara; Takuji Hirose
  CRYSTAL GROWTH & DESIGN, 巻：14, 号：7, 開始ページ：3549, 終了ページ：3556, 2014年07月, ［査読有り］
  Chirality switching in the optical resolution of mandelic acid (MA) using (1R,2S)-2-amino-1,2-diphenylethanol (ADPE) in C1-C4 alcohols is demonstrated herein. Recrystallization of the diastereomeric mixture of the MA salts from longer alcohol solvents (n-PrOH, s-BuOH, i-BuOH, and n-BuOH) produced the (R)-MA salt, whereas the (S)-MA salt was preferentially deposited from shorter alcohol solvents (MeOH, EtOH, i-PrOH, and t-BuOH). Thermogravimetric analysis and H-1 NMR spectroscopy showed that all the solvents employed were incorporated in the diastereomeric salts and the stability of the incorporated alcohols increased with an increase in the effective surface area of their alkyl chains. The X-ray crystal structures of the eight solvated diastereomeric salt pairs revealed that the type of hydrogen-bonding network (sheetlike or columnar) and the arrangement of the columnar structures were controlled by the length of the included alcohol. By comparison of the two diastereomeric MA salt crystal structures, their relative stability to display chirality switching was investigated.
  AMER CHEMICAL SOC, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1021/cg500483p
  DOI ID：10.1021/cg500483p, ISSN：1528-7483, eISSN：1528-7505, ORCID：27611392, Web of Science ID：WOS:000339090400045
• Synthesis of cyclic carbonates from CO2 and epoxides catalyzed by low loadings of benzyl bromide/DMF at ambient pressure　　　　　　　　　　　　　　　
  Lin Wang; Li Lin; Guangyou Zhang; Koichi Kodama; Mikio Yasutake; Takuji Hirose
  CHEMICAL COMMUNICATIONS, 巻：50, 号：94, 開始ページ：14813, 終了ページ：14816, 2014年, ［査読有り］
  An efficient, metal-free catalytic system for the conversion of CO2 and epoxides to cyclic carbonates under mild conditions with good-to-excellent yields (57-99%) was developed. A possible reaction mechanism involving the electrophilic activation of epoxides by benzyl cations and nucleophilic activation of CO2 by DMF is proposed.
  ROYAL SOC CHEMISTRY, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1039/c4cc06791f
  DOI ID：10.1039/c4cc06791f, ISSN：1359-7345, eISSN：1364-548X, ORCID：27611396, Web of Science ID：WOS:000344460300027
• Direct enantioseparation of 1-(2-hydroxyphenyl) ethylamines via diastereomeric salt formation: chiral recognition mechanism based on the crystal structure　　　　　　　　　　　　　　　
  Koichi Kodama; Naoki Hayashi; Mikidai Fujita; Takuji Hirose
  RSC ADVANCES, 巻：4, 号：49, 開始ページ：25609, 終了ページ：25615, 2014年, ［査読有り］
  In this study, the direct enantioseparation of unprotected 1-(2-hydroxyphenyl) ethylamines (1a and 1b) via diastereomeric salt formation is reported. After the one-pot synthesis of racemic 1, the screening of seven acidic chiral resolving agents showed that the extraction of (S)-naproxen (6) with dibenzoyl-L-tartaric acid (5) afforded the corresponding 1 : 1 diastereomeric salts that were suitable for the resolution of 1a and 1b. The optimization of the solvents resulted in high efficiencies for the resolution of 1a$ 6 in aqueous alcohols, which was consistent with the fact that the incorporated water molecules in the less-soluble diastereomeric salt reinforced its hydrogen-bonding network. For the efficient enantioseparation of rac-1b with 5, the intramolecular CH...O hydrogen bond played an important role in the chiral recognition.
  ROYAL SOC CHEMISTRY, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1039/c4ra00414k
  DOI ID：10.1039/c4ra00414k, ISSN：2046-2069, ORCID：27611393, Web of Science ID：WOS:000338434500020
• Synthesis and spectral properties of ruthenium(II) complexes based on 2,2 '-bipyridines modified by a perylene chromophore　　　　　　　　　　　　　　　
  Koichi Kodama; Akinori Kobayashi; Takuji Hirose
  TETRAHEDRON LETTERS, 巻：54, 号：40, 開始ページ：5514, 終了ページ：5517, 2013年10月, ［査読有り］
  Five new 2,2'-bipyridines functionalized with a perylene or a perylenediimide moiety were synthesized and the corresponding heteroleptic ruthenium(II) complexes ([Ru(bpy)(2)(L)](PF6)(2); bpy = 2,2'-bipyridyl, L = perylene-substituted bpy ligand) were prepared. The UV-vis spectra of the ruthenium(II) complexes showed red-shifted and intense absorption bands derived from the conjugated structure of the new ligands. (C) 2013 Elsevier Ltd. All rights reserved.
  PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.tetlet.2013.07.150
  DOI ID：10.1016/j.tetlet.2013.07.150, ISSN：0040-4039, ORCID：27611398, Web of Science ID：WOS:000324452100024
• Solvent-Induced Reversed Stereoselectivity in Reciprocal Resolutions of Mandelic Acid and erythro-2-Amino-1,2-diphenylethanol　　　　　　　　　　　　　　　
  Hiroaki Shitara; Toshiki Shintani; Koichi Kodama; Takuji Hirose
  JOURNAL OF ORGANIC CHEMISTRY, 巻：78, 号：18, 開始ページ：9309, 終了ページ：9316, 2013年09月, ［査読有り］
  Solvent-induced chirality switching in reciprocal optical resolution between mandelic acid (1) and erythro-2-amino-1,2-diphenylethanol (2) has been demonstrated. The stereochemistry of the deposited salts was controlled by changing the crystallization solvent from 1-PrOH or 1-BuOH to 1,4-dioxane. It was revealed from H-1 NMR spectra, salts that an euimolar amount of the crllization solvent thermogravimetric analysis, and X-ray crystallography of the q ysta was incorporated in each diastereomeric salt. On the basis of the crystal structures, it was found that both the hydrogen- bonding ability and the size of the solvent molecule played an important role. Differences in the formed hydrogen-bonding networks (columnar or sheetlike structure) and their packing manner were found to be crucial for the reversed stereoselectivity. Furthermore, pseudopolymorphic salt crystals that incorporated 1,4-dioxane were obtained during the enantioseparation of racemic 2, and their solid-state properties were examined by measurement of their IR spectra. This solvent-induced dual stereocontrol technique was successfully applied to the successive resolution process, eliminating the need to change the resolving agent for access to both enantiomers of 1 and 2.
  AMER CHEMICAL SOC, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1021/jo401517q
  DOI ID：10.1021/jo401517q, ISSN：0022-3263, ORCID：27611397, Web of Science ID：WOS:000330159500040
• Dielectrically controlled resolution (DCR) of 3-aminopiperidine via diastereomeric salt formation with N-tosyl-(S)-phenylalanine　　　　　　　　　　　　　　　
  Rumiko Sakurai; Kenichi Sakai; Koichi Kodama; Masanori Yamaura
  TETRAHEDRON-ASYMMETRY, 巻：23, 号：3-4, 開始ページ：221, 終了ページ：224, 2012年02月, ［査読有り］
  A useful key intermediate for the dipeptidyl peptidase-4 (DPP-4) inhibitor, 3-aminopiperidine 1, was successfully resolved with an enantiomerically pure resolving agent, N-tosyl-(S)-phenylalanine 2, to give both stereoisomers (R)-1 and (S)-1 as a less-soluble diastereomeric salt with (S)-2, via a dielectrically controlled resolution (OCR) phenomenon. (C) 2012 Elsevier Ltd. All rights reserved.
  PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.tetasy.2012.02.002
  DOI ID：10.1016/j.tetasy.2012.02.002, ISSN：0957-4166, ORCID：27611400, Web of Science ID：WOS:000302973900005
• Enantioseparation of 1-arylethanols via a supramolecular chiral host consisting of N-(2-naphthoyl)-L-aspartic acid and an achiral diamine　　　　　　　　　　　　　　　
  Koichi Kodama; Ayaka Kanno; Eriko Sekine; Takuji Hirose
  ORGANIC & BIOMOLECULAR CHEMISTRY, 巻：10, 号：9, 開始ページ：1877, 終了ページ：1882, 2012年, ［査読有り］
  A supramolecular chiral host consisting of N-(2-naphthoyl)-L-aspartic acid (L-1) and meso-1,2-diphenylethylenediamine (2) is effective in enantioseparation of 1-arylethanols (up to 96% ee with 100% inclusion ratio). Here we report three different methods to prepare the inclusion crystals and discuss the chiral recognition mechanism on the basis of X-ray crystallography results.
  ROYAL SOC CHEMISTRY, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1039/c2ob06475h
  DOI ID：10.1039/c2ob06475h, ISSN：1477-0520, ORCID：27611401, Web of Science ID：WOS:000300047600024
• Cyanative self-condensation of aromatic aldehydes promoted by VO((OPr)-Pr-i)(3)-Lewis base as a cooperative catalyst　　　　　　　　　　　　　　　
  Koichi Kodama; Hiroaki Kawamata; Naoya Takahashi; Takuji Hirose
  ORGANIC & BIOMOLECULAR CHEMISTRY, 巻：10, 号：47, 開始ページ：9440, 終了ページ：9446, 2012年, ［査読有り］
  Self-condensation of aromatic aldehydes with trimethylsilyl cyanide proceeded by the cooperative catalytic effect of VO((OPr)-Pr-i)(3) and a Lewis base to give the corresponding O-acylated cyanohydrins. The reaction conversion and selectivity were strongly dependent on the solvent used, the Lewis base, and the presence of oxygen. All the nine kinds of aromatic aldehydes considered herein afforded the O-acylated cyanohydrins with excellent selectivity under an O-2 atmosphere.
  ROYAL SOC CHEMISTRY, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1039/c2ob26811f
  DOI ID：10.1039/c2ob26811f, ISSN：1477-0520, ORCID：27611399, Web of Science ID：WOS:000311161900017
• Synthesis of Chiral 1,3-Diamines Derived from cis-2-Benzamidocyclohexanecarboxylic Acid and Their Application in the Cu-Catalyzed Enantioselective Henry Reaction　　　　　　　　　　　　　　　
  Koichi Kodama; Kazuyuki Sugawara; Takuji Hirose
  CHEMISTRY-A EUROPEAN JOURNAL, 巻：17, 号：48, 開始ページ：13584, 終了ページ：13592, 2011年11月, ［査読有り］
  In this study, 13 different chiral 1,3-diamines were synthesized from (-)-cis-2-benzamidocyclohexanecarboxylic acid. They were successfully applied as ligands in the Cu-catalyzed asymmetric Henry reaction between benzaldehyde and nitromethane. It was confirmed that the enantioselectivity of the product could be controlled by the substituents on the two amino groups. A time-course study revealed a decrease in product enantioselectivity caused by spontaneous retro-Henry reaction, which was suppressed by conducting the reaction at 0 degrees C. This versatile reaction afforded various beta-nitroalcohols in excellent yields and enantioselectivities (up to 98% yield, 91% enantiomeric excess) under the optimized reaction conditions. The chiral induction mechanism was explained on the basis of a previously proposed transition-state model.
  WILEY-V C H VERLAG GMBH, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1002/chem.201102136
  DOI ID：10.1002/chem.201102136, ISSN：0947-6539, ORCID：27611406, Web of Science ID：WOS:000298059600027
• Construction of Hydrogen-Bonded Ternary Organic Crystals Derived from L-Tartaric Acid and Their Application to Enantioseparation of Secondary Alcohols　　　　　　　　　　　　　　　
  Koichi Kodama; Eriko Sekine; Takuji Hirose
  CHEMISTRY-A EUROPEAN JOURNAL, 巻：17, 号：41, 開始ページ：11527, 終了ページ：11534, 2011年10月, ［査読有り］
  Ternary organic crystals consisting of an l-tartaric acid-derived dicarboxylic acid, a commercially available achiral diamine, and a chiral secondary alcohol have been developed and characterized by X-ray crystallography. 1D, 2D, and 3D hydrogen-bonded supramolecular networks were constructed, depending on the structure of the diamine used. Benzylic and aliphatic secondary alcohols were enantioselectively incorporated into the crystal and were successfully enantioseparated with up to 86 and 79% enantiomeric excess (ee), respectively. Selective incorporation of one enantiomer of 2-butanol, which is a small chiral aliphatic alcohol, was achieved by the cooperative effects of hydrogen bonds, CH center dot center dot center dot pi interactions, and van der Waals interactions between the guest and host molecules, with the aid of two water molecules. The high host potential of the binary supramolecular system is mainly attributed to the skewed conformation of two rigid aromatic groups of tartaric acid derivatives, which prevents dense packing of the molecules and enhances the formation of multicomponent inclusion crystals.
  WILEY-BLACKWELL, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1002/chem.201101839
  DOI ID：10.1002/chem.201101839, ISSN：0947-6539, ORCID：27611402, Web of Science ID：WOS:000297014400021
• Switching of Enantioselectivity in the Catalytic Addition of Diethylzinc to Aldehydes by Regioisomeric Chiral 1,3-Amino Sulfonamide Ligands　　　　　　　　　　　　　　　
  Takuji Hirose; Kazuyuki Sugawara; Koichi Kodama
  JOURNAL OF ORGANIC CHEMISTRY, 巻：76, 号：13, 開始ページ：5413, 終了ページ：5428, 2011年07月, ［査読有り］
  Twenty chiral 1,3-amino sulfonamides of two classes (2a-i and 3a-k) have been prepared from (-)-cis-2-benzamidocyclohexanecarboxylic acid (1) and studied as ligands for catalytic enantioselective addition of Et2Zn to a variety of aromatic and aliphatic aldehydes. The ligands 2 and 3 are, regioisomers in which the position of the amine and sulfonamide groups is exchanged. Each class of ligands with the same chirality was shown to afford sec-alcohols with the opposite stereochemistry. Structural surveys revealed that the combination of tertiary amino and p-toluenesufonylamido groups works most effectively for the reaction. Through optimization of the structural and reaction conditions, the best ligands quantitatively provided both enantiomeric secondary alcohols in good to excellent enantioselectivity of up to 9496 and 98% ee for (S)- and (R)-enantiomers, respectively.
  AMER CHEMICAL SOC, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1021/jo200834n
  DOI ID：10.1021/jo200834n, ISSN：0022-3263, ORCID：27611405, Web of Science ID：WOS:000291920900026
• Solvent-Induced Chirality Control in the Enantioseparation of 1-Phenylethylamine via Diastereomeric Salt Formation　　　　　　　　　　　　　　　
  Koichi Kodama; Yuria Kimura; Hiroaki Shitara; Mikio Yasutake; Rumiko Sakurai; Takuji Hirose
  CHIRALITY, 巻：23, 号：4, 開始ページ：326, 終了ページ：332, 2011年04月, ［査読有り］
  Solvent-induced chirality control in the enantioseparation of 1-phenylethylamine 1 by N-(p-toluenesulfonyl)-(S)-phenylalanine 2 via diastereomeric salt formation was studied. (S)-1.(S)-2 was preferentially crystallized as a less-soluble salt from aqueous alcohol, while (R)-1.(S)-2 salt was mainly obtained by addition of solvents with a six-membered ring such as dioxane, cyclohexane, tetrahydropyran, and cyclohexene to 2-propanol. Further investigations were carried out from the viewpoints of molecular structures, optical rotation measurement, and X-ray crystallographic analyses. Crystallographic analyses have revealed that incorporation of the six-membered ring solvent molecule in (R)-1.(S)-2 without hydrogen bonds changed the molecular conformation of (S)-2 to stabilize the salt, which changed the selectivity of 1 in the enantioseparation. Chirality 23:326-332, 2011. (C) 2010 Wiley-Liss, Inc.
  WILEY-BLACKWELL, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1002/chir.20922
  DOI ID：10.1002/chir.20922, ISSN：0899-0042, ORCID：27611403, Web of Science ID：WOS:000288087700007
• Structural effects of polyethers and ionic liquids in their binary mixtures on lower critical solution temperature liquid-liquid phase separation　　　　　　　　　　　　　　　
  Koichi Kodama; Ryohei Tsuda; Kazuyuki Niitsuma; Takashi Tamura; Takeshi Ueki; Hisashi Kokubo; Masayoshi Watanabe
  POLYMER JOURNAL, 巻：43, 号：3, 開始ページ：242, 終了ページ：248, 2011年03月, ［査読有り］
  The solubility and phase behavior of five polyethers (poly(ethylene oxide), poly(glycidyl methyl ether), poly(ethyl glycidyl ether), poly(ethoxyethyl glycidyl ether) and poly(propylene oxide)) in 14 different room- temperature ionic liquids (ILs) were studied by changing the structures of polyethers and the cations and anions in the ILs. Certain combinations of a polyether and an IL binary mixture exhibited lower critical solution temperature (LCST) phase behavior. For ILs containing the same anions, the polyethers were highly soluble in imidazolium- or pyridinium- based ILs, whereas they were insoluble in ammonium- or phosphonium- based ILs. An increase in length of the alkyl chain in the imidazolium cation and an increase in polarity of the polyethers resulted in a higher LCST phase separation temperature, whereas substitution of the hydrogen atoms on the imidazolium ring by methyl groups resulted in a lower LCST phase separation temperature. The hydrogen bonding interaction between the oxygen atoms in the polyethers and the aromatic hydrogen atoms on the cations in the ILs had an important role in the LCST phase behavior of the mixtures. Miscibility of the mixtures was also affected by the Lewis basicity of the anions in the ILs. Polymer Journal (2011) 43, 242-248; doi: 10.1038/pj.2010.140; published online 19 January 2011
  NATURE PUBLISHING GROUP, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1038/pj.2010.140
  DOI ID：10.1038/pj.2010.140, ISSN：0032-3896, ORCID：27611404, Web of Science ID：WOS:000288066000002
• Self-assembled proline-amino thioureas as efficient organocatalysts for the asymmetric Michael addition of aldehydes to nitroolefins　　　　　　　　　　　　　　　
  Wan-Hui Wang; Takeshi Abe; Xiang-Bo Wang; Koichi Kodama; Takuji Hirose; Guang-You Zhang
  TETRAHEDRON-ASYMMETRY, 巻：21, 号：24, 開始ページ：2925, 終了ページ：2933, 2010年12月, ［査読有り］
  A small co-catalyst library of amino thioureas has been established from chiral 1,3-diamines. These bifunctional thioureas can form assemblies with proline to cooperatively catalyze the asymmetric Michael addition of aldehydes to nitroolefins. Both the reaction rate (up to 98% yield for 18 h) and the enantioselectivity (up to 94% ee) were significantly improved upon in less polar solvents. (C) 2010 Elsevier Ltd. All rights reserved.
  PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.tetasy.2010.11.025
  DOI ID：10.1016/j.tetasy.2010.11.025, ISSN：0957-4166, ORCID：27611410, Web of Science ID：WOS:000287295400006
• Novel chiral ammonium ionic liquids as efficient organocatalysts for asymmetric Michael addition of aldehydes to nitroolefins　　　　　　　　　　　　　　　
  Wan-Hui Wang; Xiang-Bo Wang; Koichi Kodama; Takuji Hirose; Guang-You Zhang
  TETRAHEDRON, 巻：66, 号：27-28, 開始ページ：4970, 終了ページ：4976, 2010年07月, ［査読有り］
  Two chiral ammonium ionic liquids 1a and 1b have been newly synthesized from commercially available (+)-cis-2-benzamidocyclohexanecarboxylic acid. These CILs have been demonstrated to be efficient organocatalysts for asymmetric Michael addition of aldehydes to nitroolefins with excellent yields (up to 99%), high enantioselectivities (up to 90%) and modest to high diastereoselectivities (syn/anti ratio up to 99/1). (C) 2010 Elsevier Ltd. All rights reserved.
  PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.tet.2010.05.030
  DOI ID：10.1016/j.tet.2010.05.030, ISSN：0040-4020, ORCID：27611409, Web of Science ID：WOS:000279126700008
• Chirality control in the enantioselective arylation of aromatic aldehydes catalyzed by cis-(1R,2S)-2-benzamidocyclohexanecarboxylic acid derived 1,3-aminoalcohols　　　　　　　　　　　　　　　
  Xiang-Bo Wang; Koichi Kodama; Takuji Hirose; Xiao-Feng Yang; Guang-You Zhang
  TETRAHEDRON-ASYMMETRY, 巻：21, 号：1, 開始ページ：75, 終了ページ：80, 2010年01月, ［査読有り］
  A series of chiral 1,3-aminoalcohols derived from cis-(1R,2S)-2-benzamidocyclohexanecarboxylic acid were synthesized and applied to the enantioselective arylation of aromatic aldehydes The reactions exhibited good yields (up to 90%) and moderate to high enantioselectivities (up to 99%) Not only the enantioselectivity but also the stereochemistry of the product were controlled by the substituent effect of the chiral ligands. (c) 2010 Elsevier Ltd All rights reserved
  PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.tetasy.2010.01.003
  DOI ID：10.1016/j.tetasy.2010.01.003, ISSN：0957-4166, ORCID：27611408, Web of Science ID：WOS:000275351900014
• Chirality Control by Substituents in the Asymmetric Addition of Et2Zn to Aromatic Aldehydes Catalyzed by cis-(1R,2S)-2-Benzamidocyclohexanecarboxylic Acid Derived 1,3-Aminoalcohols　　　　　　　　　　　　　　　
  Wang Xiangbo; Koichi Kodama; Takuji Hirose; Zhang Guangyou
  CHINESE JOURNAL OF CHEMISTRY, 巻：28, 号：1, 開始ページ：61, 終了ページ：68, 2010年01月, ［査読有り］
  A series of novel optically active 1,3-aminoalcohols based on cis-(1R,2S)-2-benzamidocyclohexanecarboxylic acid and trans-(1R,2R)-2-benzamidocyclohexanecarboxylic acid were synthesized and used in the asymmetric di-ethylzinc addition to aromatic aldehydes. Not only the enantioselectivity but also the stereochemistry of the product were controlled by the N-substituents and the substituents on the vicinity carbon to hydroxyl group of the cis-derivatives.
  WILEY-BLACKWELL, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1002/cjoc.201090036
  DOI ID：10.1002/cjoc.201090036, ISSN：1001-604X, ORCID：27611407, Web of Science ID：WOS:000274096800009
• Thermodynamic study on phase transitions of poly(benzyl methacrylate) in ionic liquid solvents　　　　　　　　　　　　　　　
  Takeshi Ueki; Asako Ayusawa Arai; Koichi Kodama; Sayaka Kaino; Noriko Takada; Takeshi Morita; Keiko Nishikawa; Masayoshi Watanabe
  PURE AND APPLIED CHEMISTRY, 巻：81, 号：10, 開始ページ：1829, 終了ページ：1841, 2009年10月, ［査読有り］
  The lower critical solution temperature (LCST) phase behavior of poly(benzyl methacrylate) (PBnMA) in room-temperature ionic liquids (ILs) was studied by considering the effect of the chemical structure of ILs on the phase separation temperature (T(c)). It was found that the LCST behavior of PBnMA was observed in ILs containing [NTf(2)] anions and PF(6) anions. T(c) changed significantly with a small change in the chemical structures of the cations. High-sensitivity differential scanning calorimetry (DSC) was successfully performed for studying the LCST phase separation of PBnMA in two different imidazolium-based ILs. Endothermic peaks corresponding to the phase separation of PBnMA from the ILs were clearly observed at ca. 100 degrees C in the DSC thermograms. It was experimentally verified for the first time that the negative enthalpy and entropy change of mixing of PBnMA in ILs caused the LCST phase separations. The absolute values of the thermodynamic parameters for the phase transition of PBnMA in ILs obtained in this study were much lower than those reported in previous studies for aqueous polymer solutions that exhibit LCST phase behavior, such as poly(N-isopropylarylamide) and poly(vinyl methyl ether). Small changes in the thermodynamic parameters resulted in a large change in the phase separation temperature even by small changes in the chemical structure of the ILs and polymers. The microscopic desolvation process detected from the DSC measurements was inferred to have occurred before the macroscopic phase separation detected from turbidity measurements. The dependence of the endothermic peak temperatures on the DSC scan rate was observed even at slow scan rates. These results indicate that the phase separation of PBnMA from ILs is characterized by extremely slow kinetics.
  INT UNION PURE APPLIED CHEMISTRY, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1351/PAC-CON-08-09-04
  DOI ID：10.1351/PAC-CON-08-09-04, ISSN：0033-4545, eISSN：1365-3075, ORCID：27611413, Web of Science ID：WOS:000271179300008
• Thermosensitive Self-Assembly of Diblock Copolymers with Lower Critical Micellization Temperatures in an Ionic Liquid　　　　　　　　　　　　　　　
  Saki Tamura; Takeshi Ueki; Kazuhide Ueno; Koichi Kodama; Masayoshi Watanabe
  MACROMOLECULES, 巻：42, 号：16, 開始ページ：6239, 終了ページ：6244, 2009年08月, ［査読有り］
  The aggregation behavior of diblock copolymers with lower critical micellization temperatures (LCMT) in an ionic liquid (IL) is presented for the first time. Poly(methyl methacrylate) (PMMA), poly(benzyl methacrylate) (PBnMA), and polystyrene (PSt) are known to be soluble, low-temperature-soluble and high-temperature-insoluble, and insoluble, respectively, in a typical hydrophobic IL, 1-ethyl-3-methylimidazoliumbis(trifluoromethane sulfonyl)imide. Well-defined thermosensitive diblock copolymers, consisting of PMMA as the first segment and PBnMA as the second, with different molecular weights and compositions were successfully prepared by atom transfer radical polymerization to yield P(BnMA(2.2)-b-MMA(19)), P(BnMA(7.3)-b-MMA(19)), and P(BnMA(28)-b-BnMA(41)), where the numerals represent the number-average molecular weight of each segment (M(n)/kDa). For comparison purposes, a thermo-insensitive diblock copolymer, consisting of PMMA and PSt (P(St(1.7)-b-MMA(19))), was also prepared. The LCMT thermosensitivity and self-assembled behavior of the diblock copolymers in the IL were investigated in terms of the scattering intensity and hydrodynamic radius of the particles using the dynamic light scattering technique.
  AMER CHEMICAL SOC, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1021/ma900922d
  DOI ID：10.1021/ma900922d, ISSN：0024-9297, eISSN：1520-5835, ORCID：27611414, Web of Science ID：WOS:000269043200047
• Photoisomerization-Induced Tunable LCST Phase Separation of Azobenzene-Containing Polymers in an Ionic Liquid　　　　　　　　　　　　　　　
  Takeshi Ueki; Ayuko Yamaguchi; Naoki Ito; Koichi Kodama; Junji Sakamoto; Kazuhide Ueno; Hisashi Kokubo; Masayoshi Watanabe
  LANGMUIR, 巻：25, 号：16, 開始ページ：8845, 終了ページ：8848, 2009年08月, ［査読有り］
  4-Phenylazophenyl methacrylate (AzoMA) and benzyl methacrylate (BnMA) were copolymerized to produce multistimuli-responsive polymers (P(AzoMA-r-BnMA)s) in a hydrophobic ionic liquid (IL), 1-ethyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide ([C(2)mim][NTf(2)]), as the solvent. P(AzoMA-r-BnMA)s with a maximum of ca. 4 mol % AzoMA were soluble in [C(2)mim][NTf(2)] at low temperatures, and they underwent lower critical solution temperature (LCST) phase separation with all increase in temperature. Under UV and visible light irradiation, P(AzoMA-r-BnMA)s underwent reversible photochromism of trans-to-cis and cis-to-trans isomerization, respectively. The LCST temperature differences between trans- and cis-form polymers in the IL were as large as 22 degrees C. Reversible photoinduced phase separation of the polymers was achieved at a certain temperature; at this temperature, the cis-form polymers were soluble in the IL, but the trans-form polymers were not.
  AMER CHEMICAL SOC, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1021/la901159r
  DOI ID：10.1021/la901159r, ISSN：0743-7463, ORCID：27611412, Web of Science ID：WOS:000268719900002
• Lower Critical Solution Temperature Phase Behavior of Linear Polymers in Imidazolium-Based Ionic Liquids: Effects of Structural Modifications　　　　　　　　　　　　　　　
  Koichi Kodama; Hideyuki Nanashima; Takeshi Ueki; Hisashi Kokubo; Masayoshi Watanabe
  LANGMUIR, 巻：25, 号：6, 開始ページ：3820, 終了ページ：3824, 2009年03月
  The solubility and phase behavior of linear polymethacrylate polymers, primarily poly(phenylalkyl methacrylate)s, in imidazolium-based ionic liquids (ILs) were systematically studied by changing the structure of each component. Solutions of polymethacrylates in 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C(n)mim] [NTf(2)]) showed lower critical solution temperature (LCST) phase behavior, and the phase separation temperature (T(c)) could be varied by selecting an appropriate combination of a polymer and an IL. An increase in alkyl chain length between the phenyl and ester groups in the polymer side chain decreased the T(c); alternatively, substitution of the imidazolium cation with a longer alkyl chain increased the T(c). When the same anion was used, the miscibility of the polymer/IL system was mainly determined by the alkyl chain length. T(c) could also be varied by mixing two ILs in an appropriate ratio. In addition, the kinetics of the reversible phase transition phenomena exhibited by these polymers were examined. Redissolution kinetics were largely controlled by the magnitude of the difference between T(c) and the glass transition temperature (T(g)) of the polymer (T(c) - T(g)), in addition to the mutual affinity between the polymer and the IL.
  AMER CHEMICAL SOC, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1021/la803945n
  DOI ID：10.1021/la803945n, ISSN：0743-7463, CiNii Articles ID：80020170570, Web of Science ID：WOS:000264145000072
• Enantioselective inclusion of chiral alkyl aryl sulfoxides in a supramolecular helical channel consisting of an enantiopure 1,2-amino alcohol and an achiral carboxylic acid　　　　　　　　　　　　　　　
  Yuka Kobayashi; Soetrisno; Koichi Kodama; Kazuhiko Saigo
  TETRAHEDRON-ASYMMETRY, 巻：19, 号：3, 開始ページ：295, 終了ページ：301, 2008年02月
  The enantio selective clathrate formation of alkyl aryl sulfoxides 4 was achieved with dissymmetric one-dimensional helical channels created in two-component hosts consisting of (1R,2S)-2-amino-1,2-diphenylethanol 1 and an achiral carboxylic acid, p-tert-butylbenzoic acid 2, or 2-anthraquinonecarboxylic acid 3. X-ray crystallographic analyses showed that the host framework (1R,2S)-1.3 in the single crystal of a clathrate with methyl p-methylphenyl sulfoxide 4n maintained a supramolecular helical array as those of the solvent-included single crystals (1R,2S)-1.3-EtOH(single) and (1R,2S)-1-3-H2O.THF(single), while the guest 4n molecules were highly disordered. Moreover, the X-ray powder diffraction pattern of (1R,2S)-1-3-4n(clathrate) obtained through the clathrate formation demonstrated that the molecular arrangements of (1R,2S)-1, 3, and 4n were not the same as those which appeared in (1R,2S)-1.3.4n(single); the channel was enlarged. These results are consistently explained by assuming the dynamic motion of the framework (1R,2S)-1-3 to achieve widely applicable clathrate formation. (c) 2007 Elsevier Ltd. All rights reserved.
  PERGAMON-ELSEVIER SCIENCE LTD, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1016/j.tetasy.2007.11.041
  DOI ID：10.1016/j.tetasy.2007.11.041, ISSN：0957-4166, CiNii Articles ID：80019367950, Web of Science ID：WOS:000254160800006
• LCST-type liquid-liquid phase separation behaviour of poly(ethylene oxide) derivatives in an ionic liquid　　　　　　　　　　　　　　　
  Ryohei Tsuda; Koichi Kodama; Takeshi Ueki; Hisashi Kokubo; Shin-ichiro Imabayashi; Masayoshi Watanabe
  CHEMICAL COMMUNICATIONS, 号：40, 開始ページ：4939, 終了ページ：4941, 2008年
  We present a new series of polymer-ionic liquid solutions exhibiting LCST-type liquid-liquid phase separation behaviour, and reveal their phase behaviour and intermolecular interactions based on phase diagrams and NMR analysis.
  ROYAL SOC CHEMISTRY, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1039/b810127b
  DOI ID：10.1039/b810127b, ISSN：1359-7345, CiNii Articles ID：80019936631, PubMed ID：18931745, Web of Science ID：WOS:000260411000021
• Role of the relative molecular length of the components in ternary inclusion crystals in the chiral recognition and assembly of supramolecular helical architectures　　　　　　　　　　　　　　　
  Koichi Kodama; Yuka Kobayashi; Kazuhiko Saigo
  Crystal Growth and Design, 巻：7, 号：5, 開始ページ：935, 終了ページ：939, 2007年05月
  The systematic investigation of supramolecular host systems consisting of a primary amine/carboxylic acids has been performed upon changing the molecular length of the component. The combinations of enantiopure erythro-2-amino-1,2- diphenylethanol (1) and achiral benzoic acid derivatives (2a-e) were found to be effective for the inclusion of 1-phenylethanol derivatives (3a-d) with chiral recognition. X-ray crystallographic analyses revealed that a one-dimensional (ID) helical columnar architecture was commonly constructed in the ternary inclusion crystals. However, there were two types of arrangements of the columns, anti-parallel and parallel, depending on the relative molecular length of 2/3. Similarity in molecular lengths between 2 and 3 resulted in an anti-parallel alignment of the columns, while a parallel alignment was achieved when one of the two components was much longer than the other
  the ID helical columns tend to align in an anti-parallel manner to cancel their dipole
  however, the alignment switches to a parallel manner to avoid the formation of large voids between the columns. © 2007 American Chemical Society.
  英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1021/cg060849c
  DOI ID：10.1021/cg060849c, ISSN：1528-7483, CiNii Articles ID：80018502206, SCOPUS ID：34249045766
• Two-component supramolecular helical architectures: Creation of tunable dissymmetric cavities for the inclusion and chiral recognition of the third components　　　　　　　　　　　　　　　
  Koichi Kodama; Yuka Kobayashi; Kazuhiko Saigo
  CHEMISTRY-A EUROPEAN JOURNAL, 巻：13, 号：7, 開始ページ：2144, 終了ページ：2152, 2007年
  The inclusion and chiral recognition of racemic arylalkanols by supramolecular helical architectures consisting of enantiopure primary amines and achiral carboxylic acids were thoroughly studied. Among the architectures examined, a supramolecular helical architecture composed of the salt of enantiopure erythro-2-amino- 1,2-diphenylethanol (1b) and benzoic acid (2a) was found to include a wide variety of racemic arylalkanols with recognition of their chirality. The helical architecture gave a dissymmetric 1D groove in the salt crystal, and the arylalkanols were enantioselectively included in the groove. The size and shape of the groove were tunable by proper selection of the achiral carboxylic acid component. The origin of the chiral recognition with the combination 1b/2a is discussed on the basis of Xray crystallographic analyses.
  WILEY-V C H VERLAG GMBH, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1002/chem.200601295
  DOI ID：10.1002/chem.200601295, ISSN：0947-6539, CiNii Articles ID：80018629392, PubMed ID：17154322, Web of Science ID：WOS:000244914700025
• Supramolecular architecture consisting of an enantiopure amine and an achiral carboxylic acid: Application to the enantioseparation of racemic alcohols　　　　　　　　　　　　　　　
  Y Kobayashi; K Kodama; K Saigo
  ORGANIC LETTERS, 巻：6, 号：17, 開始ページ：2941, 終了ページ：2944, 2004年08月
  Three-dimensionally dissymmetric cavities are created from an enantiopure amine and an achiral carboxylic acid, which can incorporate the third components to realize the formation of closely packed crystals. The combination demonstrates enantioselective inclusion for 20 kinds of racemic alcohols. The inclusion phenomenon occurs not only during crystallization but also in the solid state.
  AMER CHEMICAL SOC, 英語, 研究論文（学術雑誌）
  DOI：https://doi.org/10.1021/ol048948b
  DOI ID：10.1021/ol048948b, ISSN：1523-7060, CiNii Articles ID：80016845065, PubMed ID：15330653, Web of Science ID：WOS:000223296800027

• 多成分有機結晶を利用した光学分割法の開発　　　　　　　　　　　　　　　
  小玉 康一
  化学工業, 巻：69, 号：4, 開始ページ：1, 終了ページ：6, 2018年, ［責任著者］
• 温度応答性高分子－イオン液体混合系の相挙動　　　　　　　　　　　　　　　
  小玉 康一; 北沢 侑造; 上木 岳士; 渡邉 正義
  表面, 2013年
  日本語, 記事・総説・解説・論説等（学術雑誌）
• Chemistry between Polyethers and Ionic Liquids: LCST Liquid-Liquid Phase Separation　　　　　　　　　　　　　　　
  Koichi Kodama; RyoheiTsuda; Kazuyuki Niitsuma; TakashiTamura, TakeshiUeki; Hisashi Kokubo; Masayoshi Watanabe
  高分子(Hot Topics), 巻：61, 開始ページ：683, 2012年09月
  ポリエーテルとイオン液体からなる二成分系のLCST型相分離を支配する化学を論じた。
  英語, 記事・総説・解説・論説等（大学・研究所紀要）
• cis-(1R,2S)-2-ベンズアミドシクロヘキサンカルボン酸から誘導した1,3-アミノアルコールを用いた芳香族アルデヒドへの立体選択的アリール化反応における置換基による不斉制御
  廣瀬 卓司; 王 祥波; 小玉 康一; 御前 仁美; 小松 拓磨
  埼玉大学地域オープンイノベーションセンター紀要, 巻：3, 開始ページ：15, 終了ページ：21, 2011年
  A series of chiral 1,3-aminoalcohols derived from cis-(1R,2S)-2-benzamidocyclohexanecarboxylic acid were synthesized and applied in the enantioselective arylation of aromatic aldehydes. The reactions exhibited good yields (up to 90%) and moderate to high enantioselectivities (up to 99%). Not only the enantioselectivity but also the stereochemistry of the product was controlled by the substituent effect of the chiral ligands.
  埼玉大学総合研究機構地域オープンイノベーションセンター, 英語
  CiNii Articles ID：120003111441

• 低分子ゲル・超分子ゲルの設計開発と応用　　　　　　　　　　　　　　　
  鈴木, 正浩 (超分子化学), ［共著］
  シーエムシー出版, 2023年07月
  日本語, 総ページ数：iv, 234p
  CiNii Books：http://ci.nii.ac.jp/ncid/BD05166006
  ISBN：9784781317496, CiNii Books ID：BD05166006
• Comprehensive Organic Synthesis　　　　　　　　　　　　　　　
  Knochel, Paul; Molander, Gary A., ［共著］
  Elsevier, 2014年06月
  英語, 総ページ数：9806
  CiNii Books：http://ci.nii.ac.jp/ncid/BB15765432
  ISBN：0080977421, ASIN：0080977421, EAN：9780080977423, CiNii Books ID：BB15765432

• アンビデキストラスな低分子量ゲル化剤における水素結合部位の影響　　　　　　　　　　　　　　　
  第14回CSJ化学フェスタ2024, 2024年10月
  ポスター発表
• ヘキサヘリセン類に対するNMRキラルシフト試薬の開発　　　　　　　　　　　　　　　
  第14回CSJ化学フェスタ2024, 2024年10月
• 桂皮酸構造を含む液晶性トリフェニレン誘導体の合成と熱伝導材料への応用　　　　　　　　　　　　　　　
  第14回CSJ化学フェスタ2024, 2024年10月
• キラルなフッ素化β-アミノ酸のジアステレオマー塩法による光学分割　　　　　　　　　　　　　　　
  第14回CSJ化学フェスタ2024, 2024年10月
• 環状カーボネート合成における速度論的光学分割のための不斉有機触媒の開発　　　　　　　　　　　　　　　
  第14回CSJ化学フェスタ2024, 2024年10月
• 光重合性ディスコチック液晶を利用した多孔性高分子膜によるイオン性色素の選択的吸着　　　　　　　　　　　　　　　
  2024年日本液晶学会討論会, 2024年09月
• 酒石酸類縁体を用いた超分子キラルホストの開発と不斉識別への応用　　　　　　　　　　　　　　　
  日本化学会第89春季年会 講演予稿集, 2009年
  ポスター発表

• 高分子学会
• 日本化学会

• 超分子ゲルを利用した溶媒依存キラリティースイッチング光学分割法の開発　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業, 基盤研究(C), 2023年04月01日 - 2026年03月31日
  小玉 康一, 埼玉大学
  配分額（総額）：4680000, 配分額（直接経費）：3600000, 配分額（間接経費）：1080000
  本研究では、環状構造を有するキラルなβ-アミノ酸である2-アミノシクロヘキサンカルボン酸（ACHC）から誘導される低分子量ゲル化剤を合成し、得られる超分子ゲルを利用した光学分割法の確立を目指すものである。令和５年度は、ACHCから誘導されるカルボン酸型の低分子量ゲル化剤の開発および原料であるACHCの立体化学がそのゲル化能に及ぼす影響について調査した。
  ACHCの各立体異性体を調製し、それらのアミノ基に対して長鎖脂肪酸を縮合させたカルボン酸型化合物を合成し、種々の溶媒に対するゲル化能を評価した。その結果、ラセミ体よりもエナンチオマー体の方が高いゲル化能を示し、また、トランス体の方がシス体よりも高いゲル化能を示すことがわかった。トランス体のエナンチオマー（trans-1）はトルエンなどの芳香族炭化水素に対して特に高いゲル化能を示した。SEM観察、IRスペクトル測定、XRD測定、モデル化合物の単結晶構造解析の結果より、合成したtrans-1はカルボキシ基とアミド部位が関与する２カ所の水素結合によって一次元集合体を形成していると推測される。
  trans-1から得られた超分子ゲルはtrans-1のキラリティーを反映していると考えられるため、超分子ゲルを利用したアミン類に対する不斉識別能を調査した。1-フェニルエチルアミンの各エナンチオマーをゲルに添加したところ、添加したエナンチオマーの立体化学に応じて、ゲルの外観が変化し、アミンの不斉認識が可能であった。
  課題番号：23K04716
  論文ID：48235745
• キラルなアミジンを利用した弱酸性化合物の光学分割　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 基盤研究(C), 基盤研究(C), 2020年04月01日 - 2023年03月31日
  小玉 康一, 埼玉大学
  配分額（総額）：4290000, 配分額（直接経費）：3300000, 配分額（間接経費）：990000
  本研究では、弱酸性化合物であるフェノール類に対して、ジアステレオマー塩法による光学分割を適用するために、新規な光学分割剤として強塩基性のキラルなアミジンを開発し、その性能を評価することを目的とした。
  まず令和２年度はキラルなアミジンに関する知見を得るために、文献にて報告されているN,N’-二置換キラルアミジン(1)の合成を検討した。化合物１は光学活性1-フェニルエチルアミンを原料として、収率29％で合成することができた。光学分割の対象化合物として、軸性キラリティーを有する1,1’-ビ-2-ナフトール(BINOL)を用いた。しかし、化合物１とBINOLを混合して結晶化を試みたところ、BINOL単独での結晶化も観測され、ジアステレオマー塩形成における再現性が得られなかった。これはアミジンの窒素原子上に導入したキラル置換基の立体障害によるものであると考えた。そこで次に、窒素原子上に置換基を持たない、無置換キラルアミジンの合成を試みた。
  無置換キラルアミジンの合成例はあまり知られていない。そこで、入手容易なキラルカルボン酸であるナプロキセンを原料として、無置換キラルアミジンの合成を試みた。中間体としてニトリルを経由する５段階の官能基変換反応を経て、収率13％で目的とする無置換アミジンの合成に成功した。しかし、得られたアミジンは全く旋光性を示さず、その光学純度が著しく低下していることがわかった。これは、アミジン部の影響で、隣接する不斉炭素原子に置換した水素の酸性度が高くなっており、容易にラセミ化が進行したものと考えられる。
  課題番号：20K05458
• 溶媒依存キラリティースイッチングによる光学分割法の開発　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 若手研究(B), 若手研究(B), 2016年04月01日 - 2019年03月31日
  小玉 康一, 埼玉大学
  配分額（総額）：4290000, 配分額（直接経費）：3300000, 配分額（間接経費）：990000
  本研究では、ジアステレオマー塩法による光学分割において、使用する溶媒を変えることによって、得られるエナンチオマーの立体化学が変化する現象（溶媒変換法）について、その適用範囲を探索した。その結果、メタ位にハロゲン置換基を有するマンデル酸の類縁体に本方法が適用可能であることがわかり、両エナンチオマーの塩を効率的に得ることに成功した。また、結晶構造解析によって、使用した溶媒の塩結晶中への包接が重要な役割を果たしていることを明らかにした。
  課題番号：16K17888
• キラル超分子ゲル中の不斉場における光学異性体の分離　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 挑戦的萌芽研究, 挑戦的萌芽研究, 2014年04月01日 - 2016年03月31日
  小玉 康一, 埼玉大学
  配分額（総額）：3900000, 配分額（直接経費）：3000000, 配分額（間接経費）：900000
  天然アミノ酸を原料とするキラルなジカルボン酸とアキラルなジアミンの塩を用いた二成分低分子ゲル化剤を開発した。これらの塩はトルエンなどの有機溶媒のゲル化が可能であった。ゲル化能の発現にはアルキル基の疎水性と水素結合性官能基の親水性の適切なバランスが重要であることがわかった。各種の分析結果から、ゲル化剤は集合し、層状構造を形成していることが示唆された。得られた超分子ゲルを利用したアルコールの光学分割を試み、低い効率ながら、ゲル中からアルコールを立体選択的に抽出することに成功した。
  課題番号：26620163
• 有機超分子キラルホストの開発と光学分割への応用　　　　　　　　　　　　　　　
  日本学術振興会, 科学研究費助成事業 若手研究(B), 若手研究(B), 2010年 - 2011年
  小玉 康一, 埼玉大学
  配分額（総額）：4030000, 配分額（直接経費）：3100000, 配分額（間接経費）：930000
  天然に存在する安価なキラル源である酒石酸およびアミノ酸に注目し、これらから誘導したキラルなジカルボン酸とアキラルなジアミンを組み合わせることによって新規超分子キラルホストを開発した。これらのキラルホストを用い、芳香族および脂肪族アルコール類の効率的な光学分割に成功した。また、各構成成分の化学構造を変えることによって、キラル識別能を調節することができ、得られた包接結晶のX線構造解析から高い性能を示した理由を明らかにした。
  課題番号：22750119