Abstract: | The thujone-derived enone 1 is converted via enol lactone intermediates 4 and 5 to the optically active steroidal analogue 13 and the corresponding 19-norsteroid analogue 14 . The structure of 13 was determined by X-ray diffraction analysis. The acid-catalyzed cyclopropane-ring opening of 13 and ozonolysis of the resulting olefin provided the 16-keto-steroid analogue 18 . |