Investigation into the reaction between 1α,5α-epidithio steroids and electrophilic halogenating reagents: aspects of the chemistry of thiosulphenyl chlorides and thiiranium ions

Abstract

The reaction of sulphuryl dichloride with 1α,5α-epidithioandrostane-3α,17β-diol diacetate afforded a ca. 1 : 1 mixture of 1α-(chlorodithio)androst-5-ene-3α,17β-diol diacetate and 4β-chloro-1α,5α-epidithioandrostane-3α,17β-diol diacetate. These labile intermediates reacted with various nucleophiles to give a variety of products, many of which represent new or little known classes of thiosteroidal compounds. A number of these appear to arise from an unusual thiiranium ion intermediate. Possible explanations for the differing regioselectivity in the ring opening of the thiiranium ion are advanced.