Metal-bis(oxazoline) complexes: From coordination chemistry to asymmetric catalysis

Abstract

Metal-bis(oxazoline) complexes have proven to be one of the most versatile classes of chiral catalysts being able to promote a large variety of organic transformations. The coordination geometry and electronic properties play an integral role for the asymmetric induction exhibited by these complexes and, aided by X-ray structure analysis and NMR studies, rules have been recognized to understand their function. Based on the most common complex geometries observed, i.e. tri, tetra- (tetrahedral or square-planar), penta- (trigonal-bipyramidal or square-pyramidal), or hexacoordination (octahedral) a mechanistic picture has emerged that allows control of enantioselectivity in reactions in a highly predictable and tunable way, demonstrating the power of combining the knowledge of coordination chemistry and asymmetric catalysis. (c) 2007 Elsevier B.V. All rights reserved.