Zinc(II)-promoted stereospecific rearrangement of 17-hydroxy-20-oxopregnane derivatives

Abstract

A new and highly efficient method for D-homo-rearrangements in the steroid field is described. The transformation is induced by the action of zinc(II) on different 17-hydroxy-20-oxopregnanes. With 17α-hydroxy-20-oxopregnanes the reaction afforded 17aα-hydroxy-17aβ-methyl-D-homo-derivatives while under the same conditions 17β-hydroxy-20-oxopregnanes gave the corresponding 17a-epimeric-D-homo-steroids. In both cases the rearrangement was stereospecif giving the corresponding products in almost quantitative yields.