Cobalt- or copper-catalyzed synthesis of gem-difluoroallyl MIDA boronates from α-trifluoromethyl alkenes

A novel two-step synthesis of gem-difluoroallyl MIDA boronates, which are air- and moisture-stable fluorine-containing building blocks for potential applications in iterative cross-couplings, was developed. The first step involves cobalt- or copper-catalyzed defluoroborylation of alpha-trifluoromethyl alkenes with B(2)pin(2) in the absence of ligand. Next, without further purification, the resulting gem-difluroallylboronic acid pinacol ester was converted to gem-difluoroallyl MIDA boronates by heating in the presence of MIDA. (C) 2020 Elsevier Ltd. All rights reserved.