Studies toward the Enantioselective Syntheses of Oxylipins: Total Synthesis and Structure Revision of Solandelactone E

An efficient and general entry to unsaturated cyclopropane- and lactone-containing oxylipins of marine origin has been designed and applied to the first enantioselective total synthesis of solandelactone E. The synthesis, which proceeds in a total of 23 steps from commercially available materials, features a diastereoselective acetal-directed cyclopropanation of an electron-deficient diene, a regioselective Sharpless enantioselective dihydroxylation, and a stereoselective [2,3]-sigmatropic rearrangement of a selenoxide to effect a 1,3-transposition of an allylic alcohol. Comparison of spectral data for the synthetic solandelactone, thus prepared, with data in the literature led to a revision of the original structural assignments of the C(11)-epimeric solandelactones.