Preparation and cleavage reactions of some steroidal epoxides
The steroidal epoxides (12), (13), (28), and (34) have been prepared and their reactions investigated. Attempts to prepare the epoxides (12) and (13) by the action of dimethylsulphonium methylide or dimethylsulphoxonium methylide on the ketone (1) gave instead the rearranged product (2) and its methyl ether (3). Compound (2) has also been obtained by base-catalysed isomerisation of the spiro-epoxide (13). Lewis acid-catalysed rearrangement of the epoxides (12), (28), and (34) into the A-homo-B-norsteroids (16), (29), and (43) respectively is described.