THE ENANTIOSELECTIVE TOTAL SYNTHESIS OF (-)-MYLTAYLENOL

The unusual sesquiterpenoid alcohol (-)-myltaylenol (1) is synthesized by an intramolecular [4+2] cycloaddition of a chiral diene accessible from Hajos-Wiechert ketone by a sequence of reactions including stere oselective alkylation of an unsaturated ketone with thiophenylmethyl i odide as alkylation agent. As the link between diene and olefin a sulf onic ester group is used. The link permits control of the stereoselect ivity of the [4+2] cycloaddition. After this key step the sulfonic est er group can be removed under oxidative conditions by molecular oxygen as oxidation agent, leading directly to a hydroxyketone that can be c onverted to (-)-myltaylenol by successive Shapiro reaction, regioselec tive hydroboration and Wittig reaction.