Double reduction of cyclic aromatic sulfonamides: synthesis of (+)-mesembrine and (+)-mesembranol.

The synthesis of (+)-mesembrine (1) and (+)-mesembranol (2) has been achieved from the monoterpene (S)-(-)-perillyl alcohol. Key transformations include a diastereo- and regioselective Pd-mediated intramolecular Heck reaction, and a double reduction of the resultant cyclic sulfonamide, to afford the cis-3a-aryloctahydroindole skeleton.