Asymmetric catalytic cyclopropanation reactions in water

The development of environmentally benign reactions is an important goal in synthetic organic chemistry and chemical engineering. However, catalytic enantioselective reactions using transition-metal complexes in protic or aqueous solvents are limited. The current applications of asymmetric cyclopropanation will be herein reported. Distinct methodologies have been developed for carbene transfer such as the use of water-soluble catalysts or micelles in water. Carbene insertion to O-H bonds in water or alcohols catalyzed by transition-metal will also be presented since the competitive reaction with the solvent is possible. Comparison between hydrophobic and hydrophilic solvents will be discussed from an asymmetric point of view. The possibility of carbene transfer catalyzed by metalloporphyrins and heme proteins such as cytochrome P450 in water will also be discussed. (c) 2007 Elsevier B.V. All rights reserved.