Collect. Czech. Chem. Commun. 1990, 55, 2738-2755

A route to 24-epibrassinolide from ergosterol avoiding the use of osmium tetroxide

Václav Černý and Miloš Buděšínský

Institute of Organic Chemistry and Biochemistry, Czechoslovak Academy of Sciences, 166 10 Prague 6


A synthesis of (22R,23R)-2α,3α,22,23-tetrahydroxy-5α-ergostan-6-one (V) from the dienone IV via the diepoxide XXII is described. The tetrol V is a key intermediate in the synthesis of 24-epibrassinolide. The reactivity of the side chain was studied on 5α-ergost-22-en-6-one (XIV) as a model compound. 1H and 13C NMR spectra of 24-epibrassinolide derivatives are discussed.