Photo-driven metal-free multicomponent reaction between aldehydes, anilines and 4-substituted-DHPs for the synthesis of secondary amines

A photocatalyst- and transition-metal-free multicomponent reaction of readily available aldehydes, primary amines and 4-alkyl-1,4-dihydropyridines (alkyl-DHPs) for the synthesis of secondary amines at room temperature under visible light irradiation has been accomplished. This transformation occurs smoothly under mild conditions to enable facile access to various secondary amines with high efficiency, wide substrate scope and good functional group tolerance, and can be readily scaled up. The selection of solvent strongly affects the reaction outcome, and CHCl3 turns out to be optimal. Moreover, the synthetic utility of this benign protocol is further showcased by its application in the late-stage functionalization of medicinally relevant complex molecules.