Breakthrough in Chiral Photochemistry based on the Excitation of Charge-Transfer Complex

2021 Fiscal Year Final Research Report

• Project/Area Number: 18H01964
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 33010:Structural organic chemistry and physical organic chemistry-related
• Research Institution: Osaka University
• Principal Investigator: Mori Tadashi 大阪大学, 工学研究科, 准教授 (70311769)
• Co-Investigator(Kenkyū-buntansha): 西嶋 政樹 東北大学, 多元物質科学研究所, 助教 (70448017)
• Project Period (FY): 2018-04-01 – 2022-03-31
• Keywords: 不斉光反応 / 電荷移動錯体 / エキシプレックス / エントロピー制御 / 分子キラリティー / 可視光励起 / キラルルイス酸 / 励起三重項

Outline of Final Research Achievements

This study examined the chiral photoreaction between naphthoquinone and alkene mediated by the chiral Lewis acid such as oxazaborolidine derivatives. Upon complexation, the substrate immediately forms 1:2 complex in the ground state, which is partially decomplexed in the excited state upon photoirradiation. Accordingly, high enantioselectivities were attained for the straight and crossed cycloaddition products. This study thus clearly demonstrated that the excited state decomplexation is an additional clue for the control of stereoeslective outcome in the chiral photoreaction involving weak interactions. The results were presented in the international conferences as well as are published in the international journals.

Free Research Field

光化学

Academic Significance and Societal Importance of the Research Achievements

キラル光反応は、励起状態化学種の特異な反応性、立体選択性を活かした光反応に不斉情報を取り込み、高ひずみで複雑な構造を一気に構成する優れた方法論である。しかしながら、高反応性、短寿命などの制約により、効率的にキラル情報を伝達することは本質的に難しい。本研究では、ナフトキノンを基質とし、キラルルイス酸を配位させた環化付加光反応系を検討し、このような問題の解決を試みた。成果は医薬品などの新規合成法にも応用可能である。