Transformation of epiandrosterone into 3-oxa-, 3-thia-, 3-selena-, and 3-aza-17-oxaandrostanes of the 5 alpha series based on beta-scission of alkoxyl radicals.

3 beta-Hydroxy-5 alpha-androstan-17-one was transformed into 17-oxa-5 alpha-androstan-3 beta-ol in five steps involving conversion of the 17-ketone via the corresponding lactol to its hypoiodite and thence a regioselective beta-scission under irradiation to give ring D seco iodoformate, from which the 17-oxasteroids were derived. Four bisheterosteroids 3,17-dioxa-5 alpha-androstane, 3-thia-17-oxa-5 alpha-androstane, 3-aza-17-oxa-5 alpha-androstane, and 3-selena-17-oxa-5 alpha-androstane) were synthesized from 17-oxa-5 alpha-androstan-3 beta-ol via 5, 8, 8, and 9 steps, respectively, involving a second regioselective beta-scission of an alkoxyl radical as the key step.