Free-radical oxidative transformations of androst-4-ene-3β,9α,17β-triol 3,17-diacetate

Abstract

The oxidation of androst-4-ene-3β,9α,17β-triol 3,17-diacetate (2) with lead tetraacetate resulted mainly In β-fragmentation of the C(9)-C(10) bond to give a mixture of 10α- and 10β-acetoxy-Δ4-unsaturated 9,10-seco-steroidal ketones (3a and 3b) as the minor components (in ~7% yield) and the rearranged 4β-acetoxy-Δ5(10) -unsaturated 9,10-seco-9-ketone (4) as the major product (in 61% yield). Unexpectedly, when the same substrate (2) was subjected to the mercuric oxide - iodine oxidation, it underwent predominantly α-epoxidation of the olefinic double bond to produce the 4α,5α-epoxy derivative (5) (in 58% yield). © 1988.