gem-Difluorination of Alkenyl N-methyliminodiacetyl Boronates: Synthesis of α- and β-Difluorinated Alkylborons.

Organofluorine compounds are widely used in pharmaceutical, agrochemical, and materials sciences. The syntheses and applications of fluorinated organoborons facilitate the rapid and modular assemblies of fluorine-containing molecules because of the versatility of C-B bonds in diverse chemical transformations. Reported herein is a migratory geminal difluorination of aryl-substituted alkenyl N-methyliminodiacetyl (MIDA) boronates using commercially available Py⋅HF as the fluorine source and hyperiodine as the oxidant. The protocol offers facile access to α- and β-difluorinated alkylboron compounds, both of which have previously been challenging to prepare. Mild reaction conditions, broad substrate scope, good functional-group tolerance, and moderate to good yields were observed. The utility of these products is demonstrated by further transformations of the C-B bond into other valuable functional groups.