Synthesis of the optically active bicyclo[4.3.0]nonane derivative, regarded as the CD ring moiety of 12-oxygenated steroids

The optically active bicyclo[4.3.0]nonane derivative, considered to be the CD ring moiety of 12-oxygenated steroids was synthesized in the present study, which involved stereo-controlled formation of bicyclo[2.2.2]octane derivative by sequential Michael reaction, formation of tricyclo[5.2.2.02,6]undecane derivative by intramolecular pinacol coupling reaction and the CC bond cleavage by retro-aldol reaction.