| abstract |
Total synthesis of steroids with substitution in the 2,3, 6, 11 or 17 positions comprising the step of cyclization of a compound having the formula ##STR1## or analogues thereof, where X represents ═O, ##STR2## or β-substituted ##STR3## Y represents ═O, β-oriented ##STR4## or β-orientated OH, R' and R 2 may be the same or different and R' represents alkyl or aryl and R 2 represents alkyl and Z represents ether or hindered ester to form the novel compounds ##STR5## |