General Synthesis of Substituted 1,2-Dihydropyridines

A general and practical metal-free protocol for the synthesis of 1,2-dihydropyridines with wide structural/functional diversity at the ring and featuring mono, double, or spiro substitution at the sp3 position is described. The protocol entails a microwave-assisted domino reaction of a propargyl vinyl ether (secondary or tertiary) and a primary amine (aliphatic or aromatic) in toluene or methanol.