Enantioselective Chemodivergent Three-Component Radical Tandem Reactions through Asymmetric Photoredox Catalysis
Chaorui Ma, Jingyu Shen, Chaofan Qu, Tianju Shao, Shanshan Cao, Yanli Yin, Xiaowei Zhao, Zhiyong Jiang
Abstract
Chemodivergent synthesis has been achieved in asymmetric photocatalysis. Under a dual catalyst system consisting of a chiral phosphoric acid and DPZ as a photosensitizer, different inorganic bases enabled the formation of two sets of valuable products from the three-component radical tandem transformations of 2-bromo-1-arylenthan-1-ones, styrenes, and quinoxalin-2(1 H )-ones. The key to success was the distinct p K a environment, in which the radicals that formed on the quinoxalin-2(1 H )-one rings after two radical addition processes underwent either single-electron oxidation or single-electron reduction. In addition, this work represents the first use of quinoxalin-2(1 H )-ones in asymmetric photoredox catalysis.