Cu‐ and Mo‐Catalysed Expedient Synthesis of Alkynyl‐Substituted Derivatives of 1,2‐Dihydropyridines, ‐quinolines and ‐isoquinolines

An efficient synthesis of 1,2‐dihydroisoquinolines and ‐quinolines by employing dimethyl acetylenedicarboxylate activated isoquinolines and quinolines in conjuction with the CuCl2/Et3N catalytic system is described herein. Furthermore, the MoO3‐catalysed alkynylation of pyridines and substituted pyridines has also been achieved. Moreover, this process has allowed the rapid synthesis of alkynyl derivatives of dihydroisoquinoline and ‐quinoline with functional group variations of the alkynyl group by using a low catalyst loading (i.e., 1 mol‐%). (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009) 1,2‐Dihydroisoquinolines, ‐quinolines and‐pyridines have been prepared by highly efficient Cu‐ and Mo‐catalysed regioselective addition of metallo‐alkynyl reagents to activated isoquinolines, quinolines and pyridines.