A Novel Rhodium‐Catalyzed Cascade Cyclization: Direct Synthesis of 3‐Substituted Phthalides from Aldehydes and Aromatic Acids

A novel rhodium(III)‐catalyzed direct functionalization of ortho CH bonds of benzoic acid derivatives and an intramolecular cyclization sequence generates 3‐substituted phthalides in moderate to good yields. This cascade cyclization involves a Grignard‐type arylation of an aldehyde and subsequent intramolecular nucleophilic substitution. No theoretical waste except for water is generated in the reaction.