Highly Efficient Three‐Component Synthesis of β‐Lactams from N‐methylhydroxylamine, Aldehydes, and Phenylacetylene

Abstract The three‐component reaction of N ‐substituted hydroxylamines, aldehydes, and phenylacetylene catalyzed by CuCl/2,2′‐bipyridine in the presence of NaOAc under neat conditions afforded the corresponding β‐lactams in good to excellent yields. Aromatic, heteroaromatic, and aliphatic aldehydes are tolerated in this reaction. The electronic effects of the aldehydes were studied for the reaction with N ‐methylhydroxylamine and N ‐benzylhydroxylamine. For N ‐methylhydroxylamine, electron‐rich aldehydes provided higher yields than electron‐deficient aldehydes, whereas for N ‐benzylhydroxylamine, no significant electronic effect was observed for the aldehydes.