Catalytic asymmetric carbon-carbon bond forming reactions catalyzed by tetrahydroisoquinoline (TIQ) N,N′-dioxide ligands

The use of TIQ-N,N'-dioxide ligands in asymmetric C-C bond forming reactions is described. In the Michael addition of cyclohexane-1,3-dione and malonates to beta,gamma-unsaturated alpha-ketoesters, excellent yields (up to 93%) and moderate to good enantioselectivities (70-89% ee) were obtained. The catalytic hetero-ene reaction of 2-methoxypropene with phenylglyoxal gave the ene product in excellent yield (95%) with moderate enantioselectivity (77% ee). The catalyst system performed well at temperatures ranging from 0 to 30 degrees C and relatively low catalyst loading (0.2-5 mol %) with dichloromethane being the preferred solvent for all reactions. (C) 2013 Elsevier Ltd. All rights reserved.