A novel synthesis of 11, 12-dimethoxyabieta-8, 11, 13-triene (4), involving the biomimetic cyclization of allylic alcohol5 is described. This represents a formal total synthesis of taxodione (1), a tumor-inhibitory diterpenoid quinone methide. Treatment of the sodium salt of8 with allyl bromide gave a 91% yield of allyl ether19 which readily underwent a Claisen rearrangement to give (after methylation with dimethyl sulfate) the dimethoxy olefin21 in ...