Visible-Light-Driven Asymmetric Deoxygenative Alkylation through NHC-Mediated Alcohol Activation and Chiral Rhodium Catalysis

The development of stereoselective catalytic methods for C(sp3)–C bond formation from abundant and readily available feedstocks remains an important objective in modern organic synthesis. Alcohols are particularly attractive in this context owing to their commercial availability, structural diversity, and widespread occurrence in nature. Despite these advantages, the use of alcohol-derived radicals in asymmetric catalysis remains largely unexplored.1-3 Herein, we report a visible-light-driven, rhodium-catalyzed enantioselective deoxygenative alkylation of α,β-unsaturated acyl imidazoles using alcohols as radical precursors. The transformation merges N-heterocyclic carbene (NHC)-mediated alcohol activation with chiral rhodium catalysis, enabling asymmetric C(sp3)–C(sp3) bond formation. A range of substituted benzyl alcohols proved suitable radical precursors, furnishing the corresponding β-alkylated acyl imidazoles in yields of up to 77% and enantiomeric ratios of up to 96:4. This methodology expands the scope of asymmetric radical conjugate additions and provides direct access to valuable enantioenriched building blocks from inexpensive commercially available alcohols.