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 ...
