Enhanced reactivity and enantioselectivity in catalytic glyoxylate-ene reactions using chiral bis(oxazoline)-copper complex in an ionic liquid

An optimal hydrophobic ionic liquid was discovered as a solvent for highly enantioselective glyoxylateene reactions catalyzed by a chiral bis(oxazoline)-copper complex. The reactivity and stereoselectivity were highly dependent upon the property of the ionic liquids; reactions between olefins and ethyl glyoxylate in [Bmim]SbF6 at ambient temperature provided remarkably enhanced reactivity and stereoselectivity, which greatly exceed those of the corresponding reactions in dichloromethane. Furthermore, the metal-ligand complex was readily recycled up to eight times while exhibiting no significant decrease in reaction efficiency. (C) 2012 Elsevier Ltd. All rights reserved.