Rhodium-Catalyzed Regioselective Olefination Directed by a Carboxylic Group

The ortho-olefination of benzoic acids can be achieved effectively through rhodium-catalyzed oxidative coupling with alkenes. The carboxylic group is readily removable to allow ortho-olefination/decarboxylation in one pot. alpha,beta-Unsaturated carboxylic acids such as methacrylic acid also undergo the olefination at the beta-position. Under the rhodium catalysis, the cine-olefination of heteroarene carboxylic acids such as thiophene-2-carboxylic acid proceeds smoothly accompanied by decarboxylation to selectively produce the corresponding vinylheteroarene derivatives.