Synthesis of 5-Hydroxy-5-vinyl-2-cyclopentenones, a Family of Rare-Type Natural Products Mostly Recovered from Marine Sources

The microwave-aided racemic synthesis of six 5-hydroxy-5-vinyl-2-cyclopentenone-type natural products was achieved. A key reaction involving the construction of the α-keto vinyl carbinol function was realized by applying a Mislow–Evans rearrangement of an allylic sulfoxide, which was prepared by conjugate addition of cyclopentane-1,3-dione-derived enolate to alkynyl sulfoxide to afford 5-hydroxy-3-methoxy-5-vinyl-2-cyclopentenone (1). From the common intermediate 1, five other congeneric natural products were synthesized.