Steroids. Part XIX. Westphalen rearrangement of 6β-azido- and 6β-cyano-5α-hydroxy-steroids. Neighbouring group participation by the azido-group
Abstract
The 6β-azido-5α-hydroxy-compound (3) and the 6β-cyano-5α-hydroxy-compound (4) rearrange to Δ9-compounds. The major product from the azido-compound (3) is 3β,5-diacetoxy-6β-azido-5α-cholestane (11), indicating significant neighbouring group participation by the azido-group. The effect of the 6β-cyano-group on reaction rate is comparable to that of a 6β-fluoro-substituent.