Regioselective C-H functionalization directed by a removable carboxyl group: palladium-catalyzed vinylation at the unusual position of indole and related heteroaromatic rings.

The palladium-catalyzed oxidative vinylation of indole-3-carboxylic acids with alkenes effectively proceeds via directed C-H functionalization and decarboxylation to produce the corresponding 2-vinylated indoles. Similarly, pyrrole-, furan-, and thiophenecarboxylic acids also undergo decarboxylative vinylation.