Modular Access to Ketones via Cooperative NHC/Pd-Catalyzed C–H Alkylation of Aldehydes with Alkyl Bromides

Direct C–H alkylation of aldehydes represents a straightforward and step-economy strategy for modular access to ketones. Herein, we report a direct C–H alkylation of aldehydes with alkyl bromides to generate ketones under cooperative NHC/Pd catalysis at room temperature. Secondary and the difficult-to-obtain tertiary alkyl-derived ketones could be prepared through this simple process under mild conditions. Mechanistic studies support the pathway involving generation of alkyl and ketyl radicals under NHC/Pd cooperative catalysis, and the following radical–radical coupling.