Cobalt/photoredox cooperative catalysis-enabled cycloisomerization reactions via sigma-bond activation

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K05051
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 33020:Synthetic organic chemistry-related
• Research Institution: Nagoya University
• Principal Investigator: Yasui Takeshi 名古屋大学, 創薬科学研究科, 助教 (70812783)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: コバルト触媒 / 光レドックス触媒 / 環化異性化反応 / σ結合活性化

Outline of Final Research Achievements

Aiming to overcome the drawback of conventional low-valent cobalt-catalyzed cyclization reactions and to explore novel reactions, we studied cycloisomerization reactions of 1,6-diynes using a cobalt/photo-redox cooperative catalyst system. As a result, we found several novel cyclization reactions that are difficult to achieve with conventional low-valent cobalt catalysts and group 9 precious metal catalysts such as rhodium and iridium catalysts. In these reactions, activation of inert σ-bonds (C-O, C-C, C-H, etc.) and asymmetric induction were achieved, leading to the development of intriguing cyclization reactions with extremely high atomic efficiency.

Free Research Field

有機合成化学

Academic Significance and Societal Importance of the Research Achievements

不飽和分子の環化異性化反応は、鎖状1次元構造から複雑な３次元多環式構造へと一挙に変換でき、結合を組み替えるだけなので、極めて原子効率の高い有用な反応である。この反応には、主にロジウムやイリジウムなどのレアメタル触媒が用いられてきたものの、ベースメタルであるコバルトの活用は遅れていた。本研究課題では、可視光エネルギーを駆動力とするコバルト/光レドックス協働触媒システムを活用し、新規環化異性化反応の開発を実施した。その結果、通常不活性なσ結合の活性化を伴う高難度の環化異性化反応を複数見出すことができた。