Catalytic Enantioselective Total Synthesis of (−)-Platyphyllide and Its Structural Revision

The catalytic asymmetric total synthesis of platyphyllide has been accomplished. A key highly substituted cyclohexene derivative has been obtained by the catalytic asymmetric Diels−Alder reaction of Danishefsky diene with an electron-deficient alkene. The Diels−Alder adduct was converted to a protected cyclohexane-1,3-dione in chiral form by catalytic Ito−Saegusa oxidation. Although the reported structure of platyphyllide was successfully synthesized, the optical rotation was opposite that of the natural compound. The absolute configuration of natural (−)-platyphyllide is revised to be a (6<i>S</i>,7<i>S</i>)-enantiomer.