Palladium-catalyzed carbonylative cyclization of aryl alkenes/alkenols: a new reaction mode for the synthesis of electron-rich chromanes.

The Pd(II)-catalyzed intramolecular carbonylative cyclization reaction of aryl alkenes and aryl alkenols is reported for the synthesis of structurally diverse chromanes. PdCl2(CH3CN)2 was used as the catalyst and CuCl2 as the oxidant under the balloon pressure of CO. The reaction is conducted under mild conditions, and chromane-type esters and lactones can be generated in a highly regio- and stereoselective manner.