Asymmetric synthesis of the β-lactam framework via a three-component coupling reaction

Abstract

The reaction of the chiral lithium amide 4 with the dienoate 5a provides regio- and stereo-selectively the β-amino ester 8 in essentially quantitative yield with >99% diastereoisomeric excess, which can be converted upon sequential treatment with LiNPrⁱ₂–B(OMe)₃–MeCHO to the key intermediate 6 for the β-lactam 7 having the correct absolute configuration.