Stereoselective Synthesis of Alkenyl Fluorides and Alkynes by Defluoro Coupling of Trifluoromethyl Arenes

A practical method for the stereoselective synthesis of tri- and tetra-substituted 1,2-fluoro-borylalkenes and alkynes by defluoro / C-C coupling of aryl trifluoromethyl groups is disclosed. Transformations convert simple abundant CF₃-arenes and multifunctional organodiboron reagents in the presence of a Lewis base activator into coupled products in up to 94% yield and >98:2 Z/E selectivity. Synthetic utility is highlighted by several product transformations that access an array of diverse scaffolds.