Copper-Catalyzed Defluorinative Borylation and Silylation of gem-Difluoroallyl Groups

Stereodefined (Z)-fluoroalkenes are bioisosteres of amides and synthetic precursors to value-added fluorinated compounds, but their stereoselective synthesis remains challenging. Herein, we report a copper-catalyzed formal SN2' defluorinative borylation of 3-substituted 3,3-difluoropropenes to form 3-fluoroallylboronic esters in high yields with excellent Z/E ratios. The primary 3-fluoroallylboronic esters undergo several synthetic sequences involving SE2' substitutions, SN2' substitutions, and sigmatropic rearrangements to provide tertiary allylic fluorides.