Zhou Tai-Ping, Zhong Fangrui, Wu Yuzhou, Liao Rong-Zhen
Key Laboratory of Materials Chemistry for Energy Conversion and Storage, Ministry of Education, Hubei Key Laboratory of Bioinorganic Chemistry and Materia Medica, Hubei Key Laboratory of Materials Chemistry and Service Failure, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074, P. R. China.
Org Biomol Chem. 2021 Feb 25;19(7):1532-1540. doi: 10.1039/d0ob02330b.
Chiral photosensitizer-catalyzed stereoselective olefin cyclization has shown its significance in organic synthesis. In this work, we investigated the reaction mechanism, regioselectivity and stereoselectivity of photochemical intramolecular [2 + 2] cycloaddition reaction catalyzed by a chiral thioxanthone molecule using quantum chemical calculations. The reaction proceeded via an energy transfer from the triplet thioxanthone to the substrate, involving stepwise and sequential C-C bond formation. The first C-C bond formation was calculated to be the rate-limiting and selectivity-controlling step. The origin of stereoselectivity was found to be interaction-controlled by distortion/interaction analysis. In addition, the catalyst substituent effects (O vs. S vs. Se) on the stereoselectivity of the photocycloadditions were explored, which provides helpful mechanistic information for the design of related photoinduced reactions.
手性光敏剂催化的立体选择性烯烃环化反应在有机合成中已显示出其重要性。在本工作中，我们使用量子化学计算研究了由手性噻吨酮分子催化的光化学分子内[2 + 2]环加成反应的反应机理、区域选择性和立体选择性。该反应通过从三重态噻吨酮到底物的能量转移进行，涉及逐步和连续的碳 - 碳键形成。计算得出第一个碳 - 碳键的形成是速率限制和选择性控制步骤。通过扭曲/相互作用分析发现立体选择性的起源是相互作用控制的。此外，还探索了催化剂取代基效应（氧对硫对硒）对光环加成反应立体选择性的影响，这为相关光诱导反应的设计提供了有用的机理信息。
