Synthesis of ferrocene-labelled steroid derivatives via homogeneous catalytic methods

Carbonylative Sonogashira coupling and copper catalyzed azide–alkyne cycloaddition were used effectively in the synthesis of ferrocene-labelled steroids. Steroidal alkynyl ketones were obtained in moderate yield from 17-ethynyl steroids without the necessity for the protection of the 17β-OH group of various compounds. Unfortunately, the alkynyl ketone derivatives could not be converted to steroids with heterocyclic groups at C-17 using methylhydrazine cyclocondensation agent. At the same time, 17-triazolyl steroids with ferrocene labels were synthesized in excellent yields starting from the same substrates by a copper-catalyzed azide alkyne cycloaddition. The new compounds were characterized by 1H and 13C NMR, MS and IR.