Syntheses of Substituted 3-Methyleneisoindolin-1-ones By a Palladium-Catalyzed Sonogashira Coupling−Carbonylation−Hydroamination Sequence in Phosphonium Salt-Based Ionic liquids

Two efficient approaches for the synthesis of isoindolin-1-one derivatives in phosphonium salt ionic liquids are described. The palladium-catalyzed carbonylation-hydroamination reaction of 1-halo-2-alkynylbenzene with amines afforded the substituted 3-methyleneisoindolin-1-ones in good yields and high selectivities in favor of the Z-isomers. The target molecules could also be synthesized by the Sonogashira coupling-carbonylation-hydroamination one-pot reaction of dihalides, alkynes, and amines. Both processes can be conducted under mild conditions and tolerate a wide array of functionalized substrates.