An efficient Ir(III) catalyst for the asymmetric transfer hydrogenation of ketones in neat water

The chiral M-CsDPEN [M = Ru, Rh, Ir; CsDPEN = (R,R,R)- or (S,S,S)-N-camphorsulfonyl-1,2-diphenylethylenediamine] catalysts have been shown to be efficient for the asymmetric transfer hydrogenation (ATH) of aryl ketones by formate in neat water. Of particular note is the Ir-(R,R,R)-CsDPEN catalyst, which catalyzes the ATH of a wide range of ketones and delivers almost full conversions within a few hours at a S/C ratio of 1000 at 40 degrees C in most cases, with enantioselectivities up to 98% ee.