New synthetic methodfor efficient synthesis of bioactive natural products -biomimetic synthesis of chaxines

Chaxine and its analogues, isolated from a Chinese edible mushroom, are highly oxidized steroidal natural products. This paper describes our proposed biosynthetic routes of chaxines and an eight-step synthesis of chaxines from ergosterol, on the basis of our biosynthetic proposal, which includes photo-induced 6-7r-electrocyclic reaction of ergosterol, site and regioselective Baeyer-Villiger oxidation of 2-ene-1,4-dione, and acyloxy migration of epoxide of the resulting enol ester as key steps. This biomimetic synthesis enabled us to revise the structures of chaxine B and its analogues proposed by the spectroscopic analysis. © 2020 Society of Synthetic Organic Chemistry. All rights reserved.