Process for the preparation of 14,17 alpha -etheno-1,3,5(10)-oestratrienes

摘要

In a process for the preparation of 14,17 alpha -etheno-1,3,5(10)-oestratrienes of the general formula I <IMAGE> in which R<1> is a hydrogen atom or a methyl or acetyl group and R<2> is a hydrogen atom, an acyl, preferably acetyl, group or a trialkylsilyl, preferably trimethyl or dimethyl-tert-butylsilyl, group, compounds of the general formula II <IMAGE> in which R<1b> is a methyl or acetyl group and R<2b> is an acyl, preferably acetyl, group or a trialkylsilyl, preferably trimethyl or dimethyl-tert-butylsilyl, group and x is 1 or 2, are reduced with an electropositive metal in a free electron solvating solvent and, where appropriate, subsequently ether groups are cleaved, acetyl groups are hydrolysed or free hydroxyl groups are acetylated.