Parallel screening of asymmetric bidentate ligands in zinc catalyzed transfer hydrogenation

Development in the field of asymmetric catalysis is driven by the importance of stereochemically pure compounds in the field of pharmaceutical industry,agrochemicals and flavors. the unpredictable results given by new catalysts make the design of effective ones a long and costly work. combinatorial asymmetric catalysis is efficient tools for finding best catalysts and it helps for many catalytic systems to be screened in a short period of time to decide about their effectiveness in synthesizing stereospicific products. this work describes rapid screening of chiral asymmetric oxazoline,imine,aminal and bisimine bidentate ligands and their in situ use for catalytic transfer hydrogenation of ketone in the presence of zinc. the ligands thus prepared in situ gave nearly same results with that of the purified version. the ligands which gave more than 70% ee with excellent conversions (□90%) were readily identified. thus ligands with excellent results can be purified in bulk to save time and money.