Palladium-Catalyzed C(sp(2))-H Alkylation of Aldehyde-Derived Hydrazones with Functionalized Difluoromethyl Bromides

Abstract

A palladium-catalyzed C(sp(2))-H difluoromethylation of aldehyde-derived hydrazones using bromodifluoromethylated compounds to afford the corresponding functionalized difluoromethylketone hydrazones has been established. It is proposed that a radical/SET mechanism proceeding via a difluoroalkyl radical may be involved in the catalytic cycle. Applications of the methodology to the synthesis of α,α-difluoro-β-ketoesters and α,α-difluoroketones (RCOCF2 H) have been illustrated.

Keywords: fluorine; homogeneous catalysis; hydrazones; palladium; reaction mechanisms.