The Synthesis of Ventiloquinone L, the Monomer of Cardinalin 3.

Readily available ethyl-4-acetoxy-6,8-dimethoxynaphthalene-2-carboxylate 27 was converted into 1-[3-allyl-4-(benzyloxy)-6,8-dimethoxy-2-naphthyl)-1-ethanol 31 in seven steps. Subjection of this compound to Wacker oxidation conditions provided 5-benzyloxy-7,9-dimethoxy-1,3-dimethyl-1H-benzo[g]isochromene 32 in good yield. Hydrogenation of the isochromene afforded (±)-cis-7,9-dimethoxy-1,3-dimethyl-1H-benzo[g]isochroman-5-ol 33 as the major product, which was readily converted into ventiloquinone L.