Immobilized chiral diamino Ru complex as catalyst for chemo- and enantioselective hydrogenation

Chiral cyclohexyldiamine based Ru triphenylphosphine complex has been immobilized over mesoporous silica SBA-15 and used in the chemo- and enantioselective hydrogenation of prochiral and α,β-unsaturated ketones and imines to corresponding products. 31P NMR, SEM, TEM, XRD, N2 sorption measurements and FTIR analysis supported the retention of the complex over mesoporous silica. This catalyst was found to catalyze preferentially the hydrogenation of CO over coexisting conjugated CC linkages in the hydrogenation of α,β-unsaturated ketones with high turnover frequencies (TOF = mole of substrate converted per mole of Ru complex per hour) and gave excellent enantioselectivities in the hydrogenation of prochiral ketones compared to its homogeneous analogue. It also showed good activity in the hydrogenation of less reactive imines to secondary amines.

Graphical abstractChiral cyclohexyldiamine based Ru triphenylphosphine complex immobilized over mesoporous silica SBA-15 was found to be highly active in the chemo- and enantioselective hydrogenation of prochiral, α,β-unsaturated ketones and imines to corresponding products.Figure optionsDownload full-size imageDownload as PowerPoint slide