Pd-Catalyzed carbonylative lactonization of 2-halidearomatic aldehydes with H 2 O as a nucleophile.

A palladium-catalyzed carbonylative cyclization reaction of 2-halidebenzaldehydes with H 2 O is described, which provides a strategy for the synthesis of diversely substituted 3,3'-oxyphthalides. Notably, the obtained 3,3'-oxyphthalide could be easily transformed into 3-aryl and alkyl phthalides with excellent efficiency using organozinc reagents under mild reaction conditions.