Quinone-Initiated Photocatalytic Enantioselective Giese Radical Addition with Ethers, Thioethers, Amines, and Alkanes
Yao Luo, Yuqiao Zhou, Fengnan Xiao, Xin He, Ziwei Zhong, Qi‐Lin Zhou, Weidi Cao, Xiaohua Liu, Xiaoming Feng
Abstract
Photocatalytic enantioselective Giese radical addition with inert C(sp 3 )–H bonds represents a highly efficient and economically favorable approach to synthesizing diverse value-added chiral molecules from abundant feedstock. Herein, we disclose a quinone-initiated photocatalytic asymmetric Giese radical addition of α-substituted acrylamides with inert C(sp 3 )–H bonds by applying simple quinones as HAT photocatalysts in combination with a chiral N, N ′-dioxide/praseodymium(III) catalyst. A wide array of ethers, thioethers, selenide, amines, and alkanes can smoothly transform into the corresponding chiral α-aryl amide derivatives with satisfactory enantioselectivities (68 examples, up to 95% ee) under mild conditions. Based on spectroscopy studies and control experiments, a quinone-initiated HAT catalytic cycle was proposed, and DFT calculations revealed that the interaction between quinone and chiral Lewis acid was essential for enantio-induction in the asymmetric back hydrogen atom transfer process.