Late-Stage Hydroxycarbonylation of Aryl Thianthrenium Salts Utilizing Chloroform-COware Chemistry.

Late-stage installation of carboxylic acid groups via carbonylation is often limited by the use of toxic CO gas or expensive surrogates. While chloroform-derived CO has proven effective in two-chamber systems for aminocarbonylation, carbonylative Suzuki coupling, and ester formation from aryl iodides, direct hydroxycarbonylation remains challenging. Herein, we report a mild and efficient palladium-catalyzed hydroxycarbonylation of aryl thianthrenium salts using water as the nucleophilic source and chloroform as a CO surrogate in a two-chamber (COware) setup. The unique reactivity of aryl thianthrenium salts facilitates regioselective late-stage functionalization (LSF) of structurally complex molecules.