Synthesis of "glycospirostanes" via ring-closing metathesis.

Syntheses of "glycospirostanes" from 3beta-hydroxy-23,24-dinor-5alpha-cholano-22,16-lactone and 3alpha-hydroxy-23,24-dinor-5beta-cholano-22,16-lactone were performed. The key step of these syntheses was ring-closing metathesis of the corresponding C,O-diallyl derivative. Further elaboration of the six-membered ring F consisted of allylic hydroxylation with SeO(2) followed by OsO(4) dihydroxylation of the C24-C25 double bond. The obtained final products proved to be simultaneously O- and C-l-arabinopyranosides.