CrCl2-catalyzed α-alkylation of carbonyl compounds via a borrowing hydrogen approach

Abstract

A new and efficient catalytic system for sustainable α-alkylation of carbonyl compounds with alcohols which serve as alkylating agents via a borrowing hydrogen strategy was presented. The developed practical catalytic system includes an Earth-abundant, environmentally benign, commercially available 3d transition metal chromium salt, CrCl₂, as a catalyst and inexpensive, bench-stable triphenylphosphine as a ligand. The functional group compatibility and the synthetic value were demonstrated by scope evaluation, product derivatization, and gram-scale experiments. Moreover, this operationally simple protocol is suitable for the late-stage functionalization of complex molecules and the synthesis of N-heterocycles.