A stereodivergent construction of β-lactam skeletons via condensation of ester enolates and a chiral imine

Article abstract of DOI:10.1016/0040-4039(91)80535-E

Diastereofacial selectivity in an addition reaction of ester enolates to a chiral imine with 1,3-dioxolane, derived from (S,S)-1,4-dimethoxy-2,3-butanediol as a chiral auxiliary, could be fully regulated by the appropriate selection of metal enolates used. Addition of the lithium enolates provided (4S)-β-lactams, while the corresponding (4R)-β-lactams were obtained by the condensation of titanium enolates with the chiral imine.