Ketol formation by peracid oxidation of a tricyclic styrene

Abstract

Oxidation of 17β-hydroxy-5-methoxy-de-A-oestra-5,7,9,14-tetraene (1) with m-chloroperbenzoic acid or monoperphthalic acid yields the epimeric ketols, 14α- and 14β,17β-dihydroxy-5-methoxy-de-A-oestra-5,7,9-trien-15-one, (2) and (3) in a ratio of 6 :1. The configurations at C-14 of these ketols were assigned by ¹H n.m.r. spectral comparison with AB-aromatic steroids, and the structure of the major product (2) was confirmed by an X-ray crystallographic analysis. The 14α-ketol (2) gives the 17β-acetate (14) with acetic anhydride in pyridine, whereas the 14β-ketol (3) gives the 16-en-15-one (15).