Asymmetric annulations of benzyl bromides, CO, and N‐tosylimines for the synthesis of chiral β‐lactams and dihydropyridones have been developed by integrating the palladium‐catalyzed carbonylation and chiral Lewis base catalysis.
Abstract
A general strategy for the design of asymmetric cascade reactions using readily available halides and carbon monoxide (CO) as substrates is developed. The key is the catalytic generation of C1‐ammonium enolates for the subsequent asymmetric cascade reactions through the combination of palladium‐catalyzed carbonylation and chiral Lewis base catalysis. Utilizing this strategy, we have established asymmetric formal [1+1+4] and [1+1+2] reactions to afford chiral dihydropyridones and β‐lactams with high yields and high enantio‐ and diastereoselectivities.