Development of Acid/Radical Self-Relay Catalysis Based on One-Electron Oxidation of the Conjugate Base

2022 Fiscal Year Final Research Report

• Project/Area Number: 19K15552
• Research Category: Grant-in-Aid for Early-Career Scientists
• Allocation Type: Multi-year Fund
• Review Section: Basic Section 33020:Synthetic organic chemistry-related
• Research Institution: Tohoku University
• Principal Investigator: Kikuchi Jun 東北大学, 薬学研究科, 助教 (20802656)
• Project Period (FY): 2019-04-01 – 2023-03-31
• Keywords: 酸触媒 / カチオン / ラジカル / 光反応 / 不斉反応

Outline of Final Research Achievements

With the aim of expanding the scope of Bronsted acid-catalyzed reactions, which were generally limited to ionic reactions, we developed radical reactions through the photo-excitation of cationic intermediates, which enables them to function as strong oxidants. As a result, we found that radical reactions involving the C-H functionalization of toluene and alkenes could be achieved by photo-excitation of cationic species such as benzopyrylium and iminium cations. The study provided insights into the reaction mechanism and successfully established chiral Bronsted acid-catalyzed enantioselective radical reactions. In addition, the utilization of silyl Lewis acids and π-acidic metals as catalysts was found to expand the range of excited cationic species accessible.

Free Research Field

有機合成化学

Academic Significance and Societal Importance of the Research Achievements

本研究で開発した手法は、温和かつメタルフリーな条件下で芳香族炭化水素や単純オレフィンといった安価な炭素資源を光学活性化合物へと変換できるため、環境調和型な分子変換法の開発研究に新たな指針を与えるものとして社会的意義があると考えられる。また本研究は、酸触媒を用いた分子変換プロセスに新たな可能性を示すとともに、未だ報告例が限られている有機分子触媒による不斉ラジカル反応を実現した点で学術的に意義がある。