Synthesis of (±)-5-epi-citreoviral and (±)-citreoviral and the kinetic resolution of an allylic silane by a [3 + 2] annulation

(equation presented) The [3 + 2] annulation reaction of allylsilane 1 with an α-keto ester provided the highly substituted tetrahydrofuran 2 as a single diastereomer in high yield. The synthesis of (±)-5-epi-citreoviral and (±)-citreoviral has been accomplished with this annulation reaction as the key step. Using the pantolactone-derived α-keto ester, the allylsilane 1 has been resolved with high enantiomeric purity.