Feng Lili, Chen Xiaofan, Guo Ning, Zhou Yuqiao, Lin Lili, Cao Weidi, Feng Xiaoming
Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University Chengdu 610064 China
Chem Sci. 2023 Apr 4;14(17):4516-4522. doi: 10.1039/d3sc00919j. eCollection 2023 May 3.
A catalytic asymmetric α-C(sp)-H functionalization of alkyl silanes with benzosultams was realized by merging photoredox and chiral Lewis acid catalysis. The key to success was the choice of photocatalyst with an appropriate redox potential and non-nucleophilic solvent, providing a novel entry to chiral organosilanes containing two adjacent tri- and tetra-substituted stereocenters with high to efficient diastereo- and enantioselectivity (up to 99% ee, 94 : 6 dr) under mild reaction conditions. Based on the control experiment and spectral analysis, an initial single electron transfer reduction of a benzosultam-triggered simultaneous or stepwise electron transfer/proton transfer process was proposed to rationalize the favored C(sp)-H functionalization rather than desilylation.
通过将光氧化还原催化与手性路易斯酸催化相结合，实现了苯并磺内酰胺与烷基硅烷的催化不对称α-C(sp)-H官能团化反应。成功的关键在于选择具有合适氧化还原电位的光催化剂和非亲核性溶剂，从而在温和的反应条件下，为合成含有两个相邻的三取代和四取代立体中心的手性有机硅烷提供了一种新方法，该反应具有高至高效的非对映和对映选择性（对映体过量高达99%，非对映体比例为94:6）。基于对照实验和光谱分析，提出了苯并磺内酰胺引发的单电子转移还原过程，该过程会同时或分步发生电子转移/质子转移，从而合理地解释了为何有利于C(sp)-H官能团化反应而非脱硅反应。
