During the 1960s, a holy grail of synthetic chemists was to devise an efficient route to steroids. R. B. Woodward was one the chemists who undertook this challenge, starting from compounds known as dienones ( e.g. 1 ) and their mysterious conversion to phenols ( e.g. 2 or 3 ) under acidic conditions.

The bimolecular nucleophilic substitution reaction at saturated carbon is an icon of organic chemistry, and is better known by its mechanistic label, S _N 2 . It is normally a slow reaction, with half lives often measured in hours.