Rhodium‐Catalyzed Cascade Reaction: Aryl Addition/Intramolecular Esterification to Access 3‐Aryl and 3‐Alkenyl Phthalides

Abstract

First one and then the other: A rhodium-catalyzed addition of aryl and alkenyl boronic acids to phthalaldehyde and subsequent intramolecular esterification is described (see scheme; cod=1,5-cyclooctadiene, dppb=1,4-bis(diphenylphosphino)butane). The method is facile and practical for accessing 3-aryl and 3-alkenyl phthalides in moderate to good yields. Several functional groups are tolerated under the reaction conditions.