Palladium-catalyzed coupling of aryl iodides with 2-alkynylbenzonitriles

The reaction of 2-(2-phenylethynyl)benzonitrile (1a) with aryl iodides, in the presence of Pd(PPh3)4 and NaOCH3 in CH3OH, at refluxing temperature for 24 h, gave 3-diarylmethylideneisoindoles 3a–d in 18–56% yields. When 2-(1-hexynyl)benzonitrile (1b) was employed in this reaction, isoquinolines 2a–c were obtained in 29–34% yields and isoindoles 3e–g were obtained in 12–25% yields, respectively. Reaction of 2-ethynylbenzonitrile (1c) with 2.5 equiv. of iodobenzene for 48 h gave 3a in 45% yield along with the monocoupled adduct 3h in 6% yield.