Neighbouring group participation in the methanolysis of a vicinal diepoxide

The tetracyanoethylene catalysed methanolysis of 17ß-acetoxy-4ß,5ß:6a,7a-diepoxyandrostane afforded 17ß-acetoxy-4a,7a-oxido-5ß-hydroxy-6ß-methoxyandrostane in which the methanolysis product of the 6a,7a-epoxide has participated in the cleavage of the 4ß,5ß-epoxide; the reaction is modified however by an adjacent 3ß-hydroxy group.