| abstract |
The 26,26,26-trifluoro-1 alpha ,25-dihydroxycholecalciferol, particularly the 26,26,26-trifluoro-1 alpha ,25R-dihydroxycholecalciferol essentially free of the 25S-epimer, and the 26,26,26-trifluoro-1 alpha ,25S-dihydroxycholecalciferol essentially free of the 25R-epimer, is prepared by reacting a compound of the formula <IMAGE> wherein Y is trialkylated Si, with the carbanion of [3S-(3 alpha ,5 beta ,Z)]-2-[2-methylene-3,5-bis[(1,1 -dimethylethyl)dimethylsilyloxy]cyclohexylidene]-ethyldiphenyl phosphine oxide and removing the silyl protecting groups. It exhibits enhanced vitamin D3-like activity. |