Catalytic Asymmetric Acyl Halide−Aldehyde Cyclocondensation Reactions of Substituted Ketenes

Catalytic asymmetric acyl halide−aldehyde cyclocondensation (AAC) reactions of alkyl-substituted ketenes with structurally diverse aldehydes provide cis-disubstituted β-lactones with high enantioselectivity. The AAC reactions utilize a novel Al(III)-triamine catalyst in which the metal's dynamic coordination geometry leads to a highly selective catalyst complex. These AAC reactions represent a functional solution to highly enantioselective substituted ester enolate aldol additions.