Precise electro-reduction of alkyl halides for radical defluorinative alkylation  

作　　者：Xingxiu Yan Shengchun Wang Zhao Liu Yujie Luo Pengjie Wang Wenyan Shi Xiaotian Qi Zhiliang Huang Aiwen Lei 

机构地区：[1]Institute for Advanced Studies(IAS)and College of Chemistry and Molecular Sciences,Wuhan University,Wuhan 430072,China

出　　处：《Science China Chemistry》2022年第4期762-770,共9页中国科学（化学英文版）

基　　金：supported by the National Key Research and Development Program of China(2021YFA1500100);the National Natural Science Foundation of China(22031008);the Science Foundation of Wuhan(2020010601012192)。

摘　　要：Reported here is a precise electro-reduction strategy for radical defluorinative alkylation towards the synthesis of gem-difluoroalkenes from α-trifluoromethylstyrenes. According to the redox-potential difference of the radical precursors, direct or indirect electrolysis is respectively adopted to realize the precise reduction. An easy-to-handle, catalyst-and metal-free condition is developed for the reduction of alkyl radical precursors that are generally easier to be reduced than α-trifluoromethylstyrenes,while a novel electro-Ni-catalytic system is established for the electro-reduction of alkyl bromides or chlorides towards the electrochemical synthesis of gem-difluoroalkenes. The merit of this protocol is exhibited by its mild conditions, wide substrate scope, and scalable preparation. Mechanistic studies and DFT calculations proved that the coordination of α-trifluoromethylstyrenes to Ni-catalyst prevents the direct reduction of the alkene and, in turn, promotes the activation of alkyl bromide through halogen atom transfer mechanism.

关 键 词：electro-reductive cross-coupling gem-difluoroalkenes radical defluorinative alkylation electro/nickel catalysis C-C bonds formation 

分 类 号：O621.25[理学—有机化学]