Synthesis of chiral ferrocenyl imidazolium salts and their rhodium(I) and iridium(I) complexes

Chiral ferrocenyl imidazolium salts were obtained from optically pure ferrocenyl alcohols or acetates by substitution with retention of configurations. Their rhodium and iridium complexes were synthesized and applied to asymmetric hydrogenations. The benzimidazolylidene-iridium complex showed up to 52.6% ee in the transfer hydrogenation of 4'-methylacetophenone.