Cu-Catalyzed Multicomponent Synthesis of 1,2,3,4-Tetrahydropyrimidines

Significance

A one-pot synthesis of N-sulfonyl-2-alkylidene-1,2,3,4-tetrahydropyrimidines (A) via Cu-catalyzed three-component reaction of sulfonyl azides, terminal alkynes and α,β-unsaturated imines has been developed. The α,β-unsaturated imines could also be generated from amines and the corresponding unsaturated aldehydes in a sequential one-pot process. The substrate scope was extensively studied and the yields generally range from good to excellent. Only for R^¹ = py, a poorer yield of product (43%) was observed. The generation of the azetidine byproduct B was observed only in some cases and isolated in yields ranging from 4-28%.