Heterocycle-containing Noyori–Ikariya catalysts for asymmetric transfer hydrogenation of ketones

The synthesis of a range of N-(heterocyclesulfonyl)-functionalised Noyori-Ikariya catalysts is described. The complexes were prepared through a short sequence from C2-symmetric 1,2-diphenylethylene-1,2-diamine (DPEN) and were characterised by a range of methods including X-ray crystallography. The complexes were active catalysts for the asymmetric transfer hydrogenation (ATH) of a range of acetophenone derivatives, giving products of high ee in most cases, with notably good results for ortho-substituted acetophenones.