Homogeneous asymmetric transfer hydrogenation of ketones using a ruthenium catalyst anchored on chitosan : natural chirality at work

A pivaloyl functionalized chitosan biopolymer was used as a polyligand for the [Ru(p-cymene)Cl2] moiety. The functionalized biopolymer containing a metal to saccharide ratio of 0.33 was used as a catalyst for the asymmetric transfer hydrogenation of ketones. The reactions gave yields up to 80% and enantiomeric excesses up to 72%, with the intrinsic chirality of chitosan being the only source of enantioselection