Copper‐Catalyzed Highly Stereoselective Hydrodifluoroallylation of Cyclopropenes and Alkenyl Boronates with 3,3‐Difluoroallyl Sulfonium Salts†

Abstract

Comprehensive SummaryDespite the paramount applications of organofluorine compounds in life and materials sciences, efficient strategies for stereoselectively constructing the C(sp3)‐CF2R bond at the stereogenic center remain limited. Here, we report a copper‐catalyzed hydrodifluoroallylation of cyclopropenes and alkenyl boronates with 3,3‐difluoroallyl sulfonium salts (DFASs). The use of DFASs overcomes the previous challenge of suppressing the reduction of fluoroalkylating reagents with M‐H species. The reaction provides an array of gem‐difluoroallyl cyclopropanes and borylalkanes with high efficiency and stereoselectivity under mild reaction conditions. Using chiral phosphine ligand could provide gem‐difluoroallyl borylalkanes with high enantioselectivities, paving a new way for the catalytic asymmetric fluoroalkylation with ubiquitous alkenes. The advantages of this protocol are synthetic convenience, high functional group tolerance, and the synthetic versatility of the resulting gem‐difluoroallyl cyclopropanes and borylalkanes. The synthetic utility of this approach has also been demonstrated by the diversified transformations of the gem‐difluoroallylated products and the rapid synthesis of bioactive molecule analogs.