Fast DKR of amines using isopropyl 2-methoxyacetate as acyl donor

The dynamic kinetic resolution (DKR) of various primary amine substrates was performed using a modified version of the Backvall system. A single equivalent of isopropyl 2-methoxyacetate was used as acyl donor in combination with p-MeO Shvo complex as the racemization catalyst and Novozym 435 as the acylation catalyst. A reaction temperature of 100 degrees C was employed to ensure a high racemization rate. Adding 2,4-dimethyl-3-pentanol (DMP) as hydrogen donor at a concentration of 0.5 m successfully suppressed side product formation. Under these modified DKR conditions, complete conversion was observed for most substrates within 26 It showing both high ee values and good chemoselectivity, whereas the original system required a reaction time of 72 h. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2007).