Chiral rhodium catalysts

Homogeneous rhodium catalysts bearing chiral phosphines are a well established tool for the asymmetric hydrogenation of functionalised substrates. It is an ideal choice when the targeted substrate functional group needs to be reduced (usually a prochiral C=C bond) and a secondary chelating group is present (dehydro-aminoesters and acids, unsaturated acids, enolacetates, etc.). More than forty years after their introduction, chiral rhodium catalysts are still a productive and cost-effective tool for the asymmetric reduction of C=C bonds where transfer hydrogenation or biocatalysis solutions have a more limited scope.