Copper(II) triflate-catalyzed highly efficient synthesis of N-substituted 1,4-dihydropyridine derivatives via three-component cyclizations of alkynes, amines, and α,β-unsaturated aldehydes

A copper(II) triflate-catalyzed three-component cyclization of alkynes, amines, and α,β-unsaturated aldehydes was developed to give various 1,4-dihydropyridines in good to high yields. In addition, this efficient and practical protocol proceeded smoothly in gram scale even when the catalytic loading was reduced to 1 mol %.