A new approach to steroid dimers and macrocycles by the reaction of 3-chlorocarbonyl derivatives of bile acids with O,O-, N,N-, and S,S-dinucleophiles

The reaction of 3-chlorocarbonyl derivatives of bile acid esters with O,O-, N,N-, and S,S-dinucleophiles provides a general and efficient entry into steroid dimers with bis-carbamate, bis-carbonate, and bis-monothiocarbonate moieties in the linker fragment. The macrocyclization of the bis-carbamate 10 afforded the dimeric and tetrameric cholaphanes, 15 and 16, respectively.