A Convenient Synthesis of (±)-Taxodione, (±)-Ferruginol, and (±)-Sugiol

The condensation of β-cyclocitral (4); with 3-isopropyl-4-methoxybenzyl chloride (5) in the presence of lithium naphthalenide gave an alcohol (6), which was then oxidized to the corresponding α,β-unsaturated ketone (7). The Intramolecular cyclization of 7 with polyphosphoric acid yielded (±)-12-methoxyabieta-8,11,13-trien-6-one (8) and its cis-isomer (9), which was then successfully converted into 8 via an enol acetate (11). The 8 ketone was dem ethylated with boron tribromide to give a phenol (18), and this was then reduced with lithium aluminium hydride to yield the corresponding alcohol (19). The oxidation of the C-11 position in 19 with benzoyl peroxide gave (±)-12-benzoyloxyabieta-8,11,13-trien-6β,11-diol (20), which, on reduction with lithium aluminium hydride and subsequent oxidation with Jones reagent, afforded (±)-taxodione (1). The reductive cleavage of the hydroxyl group in 6 with dichloroaluminium hydride, followed by cyclization, gave (±)-ferruginyl methyl ether (12), which was then demethylated with boron tribromide to produce (±)-ferruginol (2). Further, the oxidation of 12 with chromium trioxide, followed by demethylation, gave (±)-sugiol (3).