Chemoselective Synthesis of Tetrahydropyrimidines and Dihydropyrrolidones through Three‐Component Reaction of Amines, 1,3,5‐Triazinanes, and Alkyne Esters

Abstract A three‐component reaction of amines, 1,3,5‐triazinanes, and alkyne esters for the construction of tetrahydropyrimidines and dihydropyrrolidones derivatives was reported. Shifting the substituent group of 1,3,5‐triazinanes led to the chemoselective synthesis. As three‐atom synthons, aryl substituted 1,3,5‐triazinanes were applied to the regioselective synthesis of tetrahydropyrimidines. Alkyl substituted 1,3,5‐triazinanes working as two‐atom synthons promoted intramolecular cyclization to generate dihydropyrrolidones analogues. The practicality of the developed methods was demonstrated by easy operation, catalyst‐free conditions, and good functional groups tolerance.