Synthesis of a potential synthon for the chiral synthesis of the corynanthe-type indole alkaloids: enantioselective total synthesis of (–)-antirhine

The chiral formylmethyl(vinyl)tetrahydro-pyranone (16), a potential versatile synthon for the chiral synthesis of the Corynanthe-type indole alkaloids, has been synthesised and converted into (–)-antirhine, the major alkaloid of Antirhea putaminosa(F. Muell.) Bail.