Novel backbone rearrangement of steroids: formation of (20R and 20S) 1β,14β-dimethyl-18,19-dinor-5β,8α,9β,10α-cholest-13(17)-enes

Two new 1-methyl rearranged sterenes were formed from cholestan-3β-ol and related compounds by a novel backbone reaction, catalysed by K10-montmorillonite; their structures were determined by 1H and 13C n.m.r. spectroscopy.