Stereoselective Synthesis of 3‑Methyleneisoindolin-1-ones via Base-Catalyzed Intermolecular Reactions of Electron-Deficient Alkynes with N‑Hydroxyphthalimides

Highly stereoselective intermolecular reactions of electron-deficient alkynes with N-hydroxy­phthalimides for efficient construction of N-unprotected 3-methylene­isoindolin-1-ones have been developed through base catalytic strategies. The reaction of alkynoates with N-hydroxy­phthalimides catalyzed by Bu3P in DMF at 150 °C gave the corresponding 3-methyleneisoindolin-1-ones with a (Z)-configuration, while the reaction of alkynoates with N-hydroxy­phthalimides catalyzed by K2CO3 in DMF at 60 °C gave the corresponding 3-methylene­isoindolin-1-ones with an (E)-configuration, and (Z)-3-methylene­isoindolin-1-ones were obtained when alkyne ketones reacted with N-hydroxy­phthalimide.