4,4-Dimethyl-A-homoandrostane epoxides

The configuration of the oxygen-containing substituent in the position 3 of some 4,4-dimethyl-A-homo-4a-androstene derivatives was determined and their epimeric 4a,5-epoxides were prepared. The acid catalysed opening of the 4a,5-epoxide ring in epoxides XV and XXIX with the trans-orientation of the substituent in the position 3 and the epoxide ring afforded the products of 5(0)n participation of the 3-substituent, i.e. 3,5-transannular epoxides XVII and XXX. 3,5-Transannular epoxides XXII, XXXIV and XXXVI were prepared as substances with a potential biological activity.