title: The role of binding constants in the efficiency of chiral catalysts immobilized by electrostatic interactions: the case of azabis(oxazoline)-copper complexes.
abstract: As shown by theoretical calculations, azabis(oxazoline)-copper complexes are considerably more stable than the analogous bis(oxazoline)-copper complexes. This enhanced stability allows them to be efficiently immobilized by means of electrostatic interactions to different anionic supports, such as clays and nafion-silica nanocomposites, without the loss of a ligand, as is observed for bis(oxazolines). As a result, enantioselectivities of around 90 % ee are obtained in the cyclopropanation reaction between styrene and ethyl diazoacetate. Moreover, the solid catalyst is easily recoverable.
authors.affiliation: Departamento de Química Orgánica, Instituto de Ciencia de Materiales de Aragón, Facultad de Ciencias, Universidad de Zaragoza-CSIC, 50009 Zaragoza, Spain.
authors.forename: José M
authors.initials: JM
authors.lastname: Fraile
authors.forename: José I
authors.initials: JI
authors.lastname: García
authors.forename: Clara I
authors.initials: CI
authors.lastname: Herrerías
authors.forename: José A
authors.initials: JA
authors.lastname: Mayoral
authors.forename: Oliver
authors.initials: O
authors.lastname: Reiser
authors.forename: Antonio
authors.initials: A
authors.lastname: Socuéllamos
authors.forename: Heiko
authors.initials: H
authors.lastname: Werner