Iodo-azide adducts of 3-methyl-Δ2-steroids; structure and solvolysis

Abstract

The action of sodium azide–iodine(I) chloride in dichloromethane on 3-methyl-5α-androst-2-ene gives a cis-iodo-azide as the major adduct. The major product from reaction in acetonitrile is one of ring contraction. These and other products can be rationalised as arising from a C-3 carbocation or from trans-diaxial opening of α- or β-iodonium ions. The effects of a crown ether and the action of thallium(I) azide–iodine are also examined. Solvolysis of the trans-diaxial 2β-iodo-3α-azide (10) gives inter alia a product where azide migration has occurred, whereas solvolysis of the trans-diaxial 3α-iodo-2β-azide (11) gives mainly products of elimination. The action of iodine(I) azide on 3-methylene-5α-androstane is also examined.