Spontaneous formation, amplification and multiplication of enantioenriched aminonitriles by using circularly polarized light and quartz as origins of chirality

2018 Fiscal Year Final Research Report

• Project/Area Number: 16K05692
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Organic chemistry
• Research Institution: Tokyo University of Science (2017-2018); University of Fukui (2016)
• Principal Investigator: Kawasaki Tsuneomi 東京理科大学, 理学部第一部応用化学科, 准教授 (40385513)
• Project Period (FY): 2016-04-01 – 2019-03-31
• Keywords: ストレッカー合成 / 不斉増幅 / エナンチオ選択的合成 / 不斉の起源 / アミノ酸 / アミノニトリル / 自己複製

Outline of Final Research Achievements

Significant amplification of ee from ca. 0.05% ee to >99.5% ee and highly enantioselective reactive crystallization was found in the Strecker-type reaction forming aminonitriles in solid-state. Based on this observation, asymmetric Strecker-type synthesis was realized, in which L- and D-amino acids enantioselectively induced the formation and amplification of their own chiral intermediates L- and D-aminonitriles, respectively. Thus, highly enantioenriched amino acids with the same structure and the same absolute configuration as that of the original compounds could be replicatively produced. Furthermore, an enantiotopic crystal surface of an achiral imine acted as an origin of chirality for the enantioselective formation of aminonitriles by the addition of HCN, therefore, a large amount of near enantiopure amino acids, with the L- and D-handedness corresponding to the molecular orientation of the imine, could be synthesized.

Free Research Field

不斉合成

Academic Significance and Societal Importance of the Research Achievements

アミノ酸に代表される生体関連化合物のホモキラリティーは、生命の起源とも関連する未解決の謎であり、多くの興味を集めている。本研究により、提唱される前生物的生成機構（ストレッカー合成）によってキラルアミノ酸が不斉増幅・増殖を伴いながら不斉自己複製する反応を明らかにした。また、中間体イミンの単結晶表面で分子配向を起源とするエナンチオ選択的シアン化水素付加反応を見出した。これまでに考えられてきたアミノ酸生成機構に不斉発生と増幅・増殖の概念を新たに導入した本結果は、アミノ酸ホモキラリティーの起源を検証する上で意義深い。