Synthesis of Ambrox® from (−)-sclareol and (+)-cis-abienol

Short and efficient syntheses of (−)-Ambrox® (12) from (−)-sclareol (1) and (+)-cis-abienol (11) are described. In constrast to previously described procedures, the transformation of 1 to 12, involving in the key step, an oxidative degradation by catalytic osmium tetroxide, in the presence of sodium periodate, has the advantage of using the more suitable sodium borohydride, as the reducing agent. The isolation and characterization of some reaction intermediates allowed us to confirm the degradation mechanism.