Chromium-Catalyzed Homoaldol Equivalent Reaction Employing a Nucleophilic Propenyl Acetate

A scalable, highly regioselective chromium-catalyzed homoaldol equivalent reaction employing 3-bromopropenyl acetate as a masked homoenolate nucleophile in additions to aromatic, aliphatic, and alpha,beta-unsaturated aldehydes under mild Cr/Mn redox conditions in good to excellent yields is reported. The resulting vinyl acetate-containing adducts are easily hydrolyzed with mild base to provide formal homoaldol adducts, or transformed to other more functionalized products by stereoselective transformations including epoxidation and cyclopropanation.