A Divergent Synthesis of the Δ~(13)-9-Isofurans

摘要

A stereodivergent total synthesis of the Δ~(13)-9-isofurans has been developed. The four core substitutedtetrahydrofurans were prepared by the Sharpless asymmetric epoxidation and Sharpless asymmetricdihydroxylation followed by cascade cyclization. The relative configuration at C-8 was inverted byoxidation followed by immediate L-Selectride reduction. The relative configuration of the C-15 diaster-eomers was assigned by (S)-Binol/LAH/EtOH reduction of the corresponding enone. This synthesis of theΔ~(13)-9-isofurans will provide sufficient material for further investigation of their biological activity.