(6R)-SO2 adduct of 1(S),3(R)-bis(tert-butyldimethylsilyloxy)-20(S)-formyl-9,10-secopregna-5,7(E),10(19)-triene

3(R)-(tert-butyldimethylsilyloxy)-20(S)-formyl-9,10-secopregna-5(Z),7(E),10(19)-triene

20(R),3(R)-(tert-butyldimethylsilyloxy)-20-(3'-cyclopropyl-3'-oxoprop-1'(E)-enyl)-9,10-secopregna-5(Z),7(E),10(19)-triene

1(S),3(R)-bis[(tert-butyldimethylsilyl)oxy]-20(R)-formyl-9,10-secopregna-5(E),7(E),10(19)-triene