| 1. |
Ryoji Hatakenaka, Nanami Nishikawa, Yuji Mikata, Hiroki Aoyama, Kohsuke Yamashita, Yoshihito Shiota, Kazunari Yoshizawa, Yuuya Kawasaki, Katsuhiko Tomooka, Shin Kamijo, Fumito Tani, Efficient Synthesis and Structural Analysis of Chiral 4,4'-Biazulene, Chemistry - A European Journal, doi.org/10.1002/chem.202400098, 2024.03. |
| 2. |
Yuuya Kawasaki, Kazunobu Igawa Tomoya Hayashibara, Yuki Seto,b Yutaro Taniguchi, Katsuhiko Tomooka, Development of DACN-NHS-ester and DACN-maleimide, and their application for the synthesis of artificial hybrid biomolecules, Chem. Commun., 10.1039/d3cc03023g, 2023.09, Yuuya Kawasaki, Kazunobu Igawa,Tomoya Hayashibara, Yuki Seto, Yutaro Taniguchi, Katsuhiko Tomooka. |
| 3. |
Kazunobu Igawa, Kazuhiro Uehara, Yuuya Kawasaki, Katsuhiko Tomooka, Stereochemical study on planar-chiral cyclic molecules using polysaccharide-based column chromatography, Chirality, org/10.1002/chir.23429, 34, 824-832, 2022.09. |
| 4. |
Katsuhiko Tomooka, Chisato Iso, Yukiho Hashimoto, Masaki Suzuki, Yuuya Kawasaki, Kazunobu Igawa, Synthesis, Stereochemical Analysis, and Transformation of Oxa-[7] orthocyclophene, CHEMISTRY LETTERS, 10.1246/cl.220219, 51, 7, 788-790, 2022.07, Planar chiral oxa-[7]orthocyclophene 1a was designed and synthesized with two different synthetic routes. X-ray crystallo-graphic analyses of 1a and its platinum complex revealed a highly distorted ring structure and the absolute stereochemistry of 1a, respectively. Epoxidation and [2,3]-Wittig rearrangement of 1a provided with central chiral molecules, without the loss of enantiomeric purity.. |
| 5. |
Kawasaki, Y.; Kamikubo, R.; Kumegawa, Y.; Ogawa, K.; Kashiwagi, T.; Ano, Y.; Igawa K.; Tomooka, K.
, Preparation of enantioenriched helical- and axial-chiral molecules by dynamic asymmetric induction, Chemical Communications
, 10.1039/d1cc05881a, 58, 1605-1608, 2022.06. |
| 6. |
Jun-ichi Hayashi, Masaki Suzuki, Maki Shimada, Yuuya Kawasaki, Kazunobu Igawa, Katsuhiko Tomooka, Synthesis and Stereochemical Analysis of Ten-membered Diallylic Nitrogen Cycle and Its Pt-Complex, CHEMISTRY LETTERS, 10.1246/cl.220143, 51, 6, 636-638, 2022.06, Newly synthesized ten-membered diallylic nitrogen cycle, having E- and Z-alkene moieties, shows labile planar-chirality at ambient temperature. VT-NMR experiments revealed the detail of the stereochemical behavior of interconversion of the enantiomers and diastereomers. In sharp contrast, Pt-complex of the nitrogen cycle have more stable planar chirality, and the enantiomers of the Pt-complex were isolated by HPLC using a chiral stationary phase.. |
| 7. |
Yuuya Kawasaki, Sumire Tanaka, Kazunobu Igawa, Katsuhiko Tomooka, SYNTHESIS AND STEREOCHEMICAL ANALYSIS OF PLANAR CHIRAL NINE-MEMBERED AZA-ORTHOCYCLOPHYNE, HETEROCYCLES, 10.3987/COM-22-S(R)18, 105, 352-357, 2022.04. |
| 8. |
Kazunobu Igawa, Shusaku Asano, Yuki Yoshida, Yuuya Kawasaki, Katsuhiko Tomooka, Analysis of Stereochemical Stability of Dynamic Chiral Molecules Using an Automated Microflow Measurement System, The Journal of Organic Chemistry, 10.1021/acs.joc.1c00914, 86, 14, 9651-9657, 2021.07, An automated microflow measurement system for the kinetic study of racemization of dynamic chiral molecules was developed. This system facilitated the analysis of fast racemization within several seconds at elevated temperatures owing to its rapid heating ability, high performance for controlling short residence times, and ease of connection to HPLC systems for direct measurement of the enantiomeric purity. A more precise analysis was realized by combination of microflow and common batch measurements over a broad range of temperatures.. |
| 9. |
Kazunobu Igawa, Yuuya Kawasaki, Sora Nozaki, Naoto Kokan, Katsuhiko Tomooka, Ozone Oxidation of Silylalkene: Mechanistic Study and Application for the Synthesis of Silacarboxylic Acid Derivatives, Journal of Organic Chemistry, 10.1021/acs.joc.9b03350, 85, 6, 4165-4171, 2020.03, Copyright © 2020 American Chemical Society. The addition-type ozone oxidation of silylalkenes is a highly efficient reaction to provide synthetically versatile α-silylperoxy carbonyl compounds. To gain insight into the reaction mechanism, we performed a computational study, which revealed that the reaction proceeds via [1,2]-Brook rearrangement-type silyl migration of primary ozonide. In sharp contrast to the addition-type reactions, the ozone oxidation of α-alkoxysilylalkenes proceeds in a cleavage-type manner to afford excellent yields of silacarboxylic acid esters via the 1,3-cycloelimination of primary ozonide prior to 1,2-silyl migration.. |
| 10. |
Ryoma Masuda, Yuuya Kawasaki, Kazunobu Igawa, Yoshiyuki Manabe, Hiroshi Fujii, Nobuo Kato, Katsuhiko Tomooka, Junko Ohkanda, Copper‐Free Huisgen Cycloaddition for the 14‐3‐3‐Templated Synthesis of Fusicoccin‐Peptide Conjugates, Chemistry – An Asian Journal, 10.1002/asia.202000042, 15, 6, 742-747, 2020.02. |
| 11. |
Igawa, K.; Kawasaki, Y.; Ano, Y.; Kashiwagi, T.; Ogawa, K.; Hayashi, J.; Morita, R. Yoshioka, Y.; Uehara, K.; Tomooka, K., Preparation of Enantioenriched Chiral Organic Molecules by Dynamic Asymmetric Induction from a Outer Chiral Source, CHEMISTRY LETTERS, 10.1246/cl.190170, 48, 7, 726-729, 2019.07. |
| 12. |
Hayashi, J.; Uehara, K.; Ano, Y.; Kawasaki, Y.; Igawa, K.; Tomooka, K., Synthesis and Stereochemical Analysis of Dynamic Planar Chiral Nine-membered Diallylic Amide:Significant Substituent Effect on Stereochemical Stability, Heterocycles, 10.3987/COM-18-S(F)92, 99, 856-864, 2019.06. |
| 13. |
Kawasaki, Y.; Yamanaka, Y.; Seto, Y.; Igawa, K.; Tomooka, K., Synthesis of NMs-DACN: Small and Hydrophilic Click Reaction Device, CHEMISTRY LETTERS, 10.1246/cl.190026, 48, 5, 495-497, 2019.05. |
| 14. |
Kazunobu Igawa, Shin Aoyama, Yuuya Kawasaki, Takeru Kashiwagi, Yuki Seto, Runyan Ni, Naoto Mitsuda, Katsuhiko Tomooka, Thieme Chemistry Journals Awardees: Where Are They Now? One-Pot Synthesis of Versatile Buckle Units for Click Chemistry: 4,8-Diazacyclononynes (DACNs), SYNLETT, 10.1055/s-0036-1588839, 28, 16, 2110-2114, 2017.10, Newly designed buckle units for copper-free click chemistry: 4,8-diazacyclononynes (DACNs) were efficiently synthesized with a one-pot procedure from commercially available 2-butyne-1,4-diol. The synthesized DACNs possess versatile connectors for the introduction of functional units and exhibit high click reactivity.. |
| 15. |
Kazunobu Igawa, Yuuya Kawasaki, Kosuke Nishino, Naoto Mitsuda, Katsuhiko Tomooka, Asymmetric Ozone Oxidation of Silylalkenes Using a C-2-Symmetrical Dialkoxysilyl Group as a Chiral Auxiliary, CHEMISTRY-A EUROPEAN JOURNAL, 10.1002/chem.201402996, 20, 30, 9255-9258, 2014.07, Ozone oxidation of silyl-substituted alkenes, namely silylalkenes, proceeds in an addition-type manner to afford alpha-silylperoxy carbonyl compounds in good to excellent yields, without the formation of normal ozonolysis products. Herein the ozone oxidation of chiral alkenylsilanes prepared from alkynes and a newly designed chiral hydrosilane is reported. The reaction affords silylperoxides with high diastereoselectivity (up to 94% d.r.). The silylperoxides are convertible into enantioenriched chiral acyloins in a stereospecific manner.. |
| 16. |
Yuuya Kawasaki, Youhei Ishikawa, Kazunobu Igawa, Katsuhiko Tomooka, Directing Group-Controlled Hydrosilylation: Regioselective Functionalization of Alkyne, JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 10.1021/ja209553f, 133, 51, 20712-20715, 2011.12, Pt(0)-catalyzed hydrosilylation of unsymmetric alkynes proceeds in a highly regioselective manner with a dimethylvinylsilyl (DMVS) group as the directing group. This hydrosilylation affords a single regioisomer of silylalkenes from propargylic and homopropargylic alcohol derivatives. DMVS also has an accelerating effect that allows group-selective hydrosilylation of the DMVS-attached alkyne prior to that of other alkynes. Combined hydrosilylation and transformation reactions of the resulting silylalkenes afford various tri-substituted alkenes and multi-oxy-functionalized compounds with high regioselectivity from unsymmetric alkynes.. |
| 17. |
Kazunobu Igawa, Yuuya Kawasaki, Katsuhiko Tomooka, Addition-type Oxidation of Silylalkene Using Ozone: An Efficient Approach for Acyloin and Its Derivatives, CHEMISTRY LETTERS, 10.1246/cl.2011.233, 40, 3, 233-235, 2011.03, Acyloins are efficiently synthesized in three steps from alkynes via hydrosilylation followed by an addition-type ozone oxidation and hydrogenation. The key intermediate alpha-silylper-oxy ketone is convertible to not only acyloin but also O-silylated acyloin and diketone.. |
