Efficient Synthesis of Tetrahydropyrimidines and Pyrrolidines by a Multicomponent Reaction of Dialkyl Acetylenedicarboxylates (=Dialkyl But-2-ynedioates), Amines, and Formaldehyde in the Presence of Iodine as a Catalyst†

摘要

Iodine was explored as an efficient catalyst for the synthesis of tetrahydropyrimidines 4 and pyrrolidines 5 by a multicomponent reaction of dialkyl acetylenedicarboxylates (=dialkyl but-2-ynedioates) 1, amines 2, and HCHO 3 at room temperature (Scheme). When the molar ratios of these substrates were 1 : 2 : 4 and 1 : 1 : 4, tetrahydropyrimidines and pyrrolidines were formed, respectively. The products were obtained in high yields (73–85%) within a short period of time (25–35 min).