Asymmetric Total Synthesis of Asperversin A.

Abstract

Asperversin A represents the first example of a steroid-sterigmatocystin heterodimer. We report the concise asymmetric total synthesis of this natural product in 11 steps (the longest linear sequence). The polycyclic ring system was constructed by a cascade dialdehyde cyclization and the late stage xanthene formation by a phenol-assisted reductive alkylation and a SNAr reaction. The acetal linkage with ergosterol peroxide was furnished by a glycosylation-inspired approach.