Enantiospecific synthesis of wiedendiol-B from (-)-sclareol and (+)-cis-abienol

The first enantiospecific synthesis of the cholesteryl ester transfer protein (CETP) inhibitor wiedendiol-B (1) is described. The drimanic synthon was prepared from (-)-sclareol (4) and (+)-cis-abienol (13) by two alternative routes. The key steps of the reaction sequences are the chemo-and diastereoselective hydrogenation of the C-8-C-9 double bond of enal 6 and the stereoselective cationic hydrogenation of the hydroxyl group of 13, respectively, and the selective reduction of benzyl groups of 15. (C) 1997 Elsevier Science Ltd.