A FORMAL TOTAL SYNTHESIS OF (±)-QUADRONE

Abstract

This article deals with a formal total synthesis of (±)-quadrone (1), an antitumor sesquiterpene. The cyclopentenone (3) was trans-formed into cyclopropane derivative (2), a regioselective reductive ring opening of which and trapping of the enolate intermediate (16) by a C-1 unit afforded the diquinaneacetate (17). By a two-step sequence 17 was converted into methyl (1R^*, 5R^*, 6R^*)-6-(2-hydroxyethyl)-7, 7-dimethyl-2-methylene-3-oxobicyclo [3. 3. 0] octane-1-acetate (19), which had already been proved to be an intermediate for (±)-1.