Efficient synthesis of isoquinolines and pyridines via copper(I)-catalyzed multi-component reaction

A wide range of 3-substituted isoquinolines, steroidal pyridines, 5,6-dihydrobenzo[f]isoquinolines and 1,6-naphthyridine were synthesized in good yield via a ligand-free copper-catalyzed three-component reaction of beta-halovinyl/aryl aldehyde, aromatic/aliphatic terminal alkyne and tert-butylamine/benzamidine in DMF under microwave irradiation. A catalyst-free reaction of ortho-alkynyl aryl/vinyl aldehydes with benzamidine under microwave irradiation also provided the 3-substituted isoquinoline and substituted pyridine derivatives in excellent yield.