Borane-Catalyzed Coupling of Diazooxindoles and Difluoroenoxysilanes to Tetrasubstituted Monofluoroalkenes

A highly stereoselective coupling reaction of diazooxindoles
with
difluoroenoxysilanes catalyzed by Lewis acidic boranes has been developed.
The reaction proceeded at ambient temperature under transition metal-free
conditions with wide functional group tolerance. By using this simple
procedure, a series of tetrasubstituted monofluoroalkenes can be accessed
in good yield with high selectivity.