Metathesis reactions of Δ22-steroids

Metathesis reactions of Δ22-steroids are studied. The cross metathesis reactions of model Δ22-steroids with excess of simple alkenes are sluggish or do not occur at all. In contrast, derivatives of both trans- and cis-Δ22-cholesterol undergo ring closing metathesis reactions but the former reacts faster. However, the side chain double bond in stigmasterol and ergosterol is too crowded for metathesis reactions promoted by currently available catalysts.