Copper-Catalyzed Stereoselective Defluorinative Borylation and Silylation of gem-Difluoroalkenes

The copper-catalyzed stereoselective defluorinative borylation and silylation of gem-difluoroalkenes was developed. The protocol led to the exclusive formation of Z type monofluoroalkenyl borons and silanes in generally good efficiency with broad substrate scope. The products formed could be readily transformed to other F-containing molecules by taking advantage of the versatile reactivities of C-B and C-Si bonds. Experimental and theoretical mechanistic studies were conducted which support an olefin insertion/syn-planar beta-F elimination pathway.