Synthesis of steroid–ferrocene conjugates of steroidal 17-carboxamides via a palladium-catalyzed aminocarbonylation – Copper-catalyzed azide–alkyne cycloaddition reaction sequence

Steroids with the 17-iodo-16-ene functionality were converted to ferrocene labeled steroidal 17-carboxamides via a two step reaction sequence. The first step involved the palladium-catalyzed aminocarbonylation of the alkenyl iodides with prop-2-yn-1-amine as the nucleophile in the presence of the Pd(OAc)2/PPh3 catalyst system. In the second step, the product N-(prop-2-ynyl)-carboxamides underwent a facile azide–alkyne cycloaddition with ferrocenyl azides in the presence of CuSO4/sodium ascorbate to produce the steroid–ferrocene conjugates. The new compounds were obtained in good yield and were characterized by 1H and 13C NMR, IR, MS and elemental analysis.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► New ferrocene labeled steroidal 17-carboxamides were produced. ► The first step was the Pd-catalyzed carbonylation of steroids with 3-amino-1-propyne. ► The products underwent a facile azide–alkyne cycloaddition with ferrocenyl azides. ► Both reactions led to the products in good yields. ► The new compounds were characterized by various spectroscopic methods.