A reusable enantioselective catalytic system for the Kharasch–Sosnovsky allylic oxidation of alkenes based on a ditopic azabis(oxazoline) ligand
摘要:
An easily recoverable and reusable enantioselective catalytic system based on the self-assembly of a coordination polymer through the use of a chiral ditopic ligand, is described for the allylic oxidation of cycloalkenes with tert-butyl perbenzoate. Upon addition of the substrates and a coordinating solvent (acetone or acetonitrile) the coordination polymer disassembles, allowing the catalysis to take place in homogeneous phase. After completion of the reaction, the catalyst reassembles as a coordination polymer upon solvent evaporation and addition of hexane, and is recovered as an insoluble solid. This way, good enantioselectivities and yields are obtained in seven consecutive operation cycles. (C) 2011 Elsevier Ltd. All rights reserved.
Energy-Resolved Collision-Induced Dissociation Cross Sections of 2:1 Bis-oxazoline Copper Complexes. Nonbonded Interactions and Nonlinear Effects
作者:Eva Zocher、Rolf Dietiker、Peter Chen
DOI:10.1021/ja065390p
日期:2007.3.1
Absolute ligand binding energies are determined for the 2:1 complexes of bis-oxazoline ligands and Cu(I) in the gas phase by the fitting of energy-resolved collision-induced dissociation cross sections. The complexes were chosen for their occurrence in asymmetriccatalysis for which the phenomenon of nonlineareffects is explained by differences in stability for homochiral and heterochiral complexes
Palladium-azabis(oxazoline) complexes proved to be highly selective and efficient in the asymmetric copolymerization of styrene and CO at ambient pressure.