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

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 (RCOCF 2 H) have been illustrated.