Reactivity and Conformation of Systems containing a Three-membered Heterocycle Conjugated with an Unsaturated Group

Steroidal epoxides, aziridines, and episulphides containing a vicinal unsaturated group (ketone or hydrazone) are used as examples to examine, systematise, and generalise reactions involving nucleophilic opening of a three-membered ring. The influence of an adjacent substituent on the structural and stereochemical trends of such reactions is discussed. A list of 107 references is included.