Palladium-Catalysed Heteroannulation with Terminal Alkynes: a Highly Regio- and Stereoselective Synthesis of (Z)-3-Aryl(alkyl)idene Isoindolin-1-ones

A highly regio- and stereoselective method for the synthesis of (Z)-3-aryl(alkyl)idene isoindolin-1-ones through palladium-copper catalysis is described. 2-Iodobenzamide 1 and its substituted derivatives 2–10 were reacted with terminal alkynes 11–19 in the presence of (PPh3)2PdCl2, CuI, and Et3N in DMF mostly at 80°C for 16 h to yield the 2-alkynyl substituted benzamides 20–38, 40–45, 77 which could then be cyclised with NaOEt in EtOH to the 3-aryl(alkyl)idene isoindolin-1-ones 46–49, 51, 53–55, 57, 59–71, 73 and 75. In certain cases, the isoindolin-1-ones 50, 52, 56 and 58 could be directly obtained by the palladium-catalysed reactions.