Synthesis of a cisplatin derivative from lithocholic acid

A new steroidal-platinum(II) hybrid compound was synthesized using a simple and efficient methodology. The synthesis was performed by a convergent approach with cross metathesis (CM) as a key step. An olefin derived from lithocholic acid and a vinyl substituted ethylenediamine derived from l-serine were used as chiral building blocks, which were combined in the CM step. The most important advantage of this method was the utilization of l-serine as a cheap, stereoisomerically pure substrate. A steroid with a diamino system in the side chain was subjected to reaction with potassium tetrachloroplatinate to obtain the target platinum(II) complex. Attempts to synthesize similar diamine systems using the asymmetric Strecker reaction were unsuccessful.