Iridium Catalysts with Chiral Imidazole-Phosphine Ligands for Asymmetric Hydrogenation of Vinyl Fluorides and other Olefins
作者:Päivi Kaukoranta、Mattias Engman、Christian Hedberg、Jonas Bergquist、Pher G. Andersson
DOI:10.1002/adsc.200800062
日期:2008.5.5
New chiral bidentate imidazole-phosphine ligands have been prepared and evaluated for the iridium-catalysed asymmetric hydrogenation of olefins. The imidazole-phosphine-ligated iridiumcatalysts hydrogenated trisubstituted olefins with the same sense of enantiodiscrimination as known iridiumcatalysts possessing oxazole and thiazole as N-donors. The imidazole-based catalysts were shown to hydrogenate
Asymmetric Hydrogenation of Imines and Olefins Using Phosphine-Oxazoline Iridium Complexes as Catalysts
作者:Anna Trifonova、Jarle S. Diesen、Pher G. Andersson
DOI:10.1002/chem.200500942
日期:2006.3.1
Herein we describe the synthesis of a new class of chiral phosphine-oxazolines and their application as ligands in iridium-catalyzed hydrogenations. Mechanistic aspects of olefin hydrogenation with this class of iridiumcatalysts are discussed and a selectivity model to help rationalize the results obtained is also presented.
Development of new thiazole-based iridium catalysts and their applications in the asymmetric hydrogenation of trisubstituted olefins
作者:Pradeep Cheruku、Alexander Paptchikhine、Muhammad Ali、Jörg-M. Neudörfl、Pher G. Andersson
DOI:10.1039/b714744a
日期:——
evaluated in the iridium-catalyzed asymmetric hydrogenation of trisubstituted olefins. Chirality was introduced into the ligands through a highly diastereoselective alkylation using Oppolzer's camphorsultam as chiral auxiliary. In general, the new catalysts are as reactive and selective as their cyclic counterparts for the asymmetric hydrogenation of various trisubstituted olefins.
Asymmetric hydrogenation of tri-substituted alkenes with Ir-NHC-thiazole complexes
作者:Klas Källström、Pher G. Andersson
DOI:10.1016/j.tetlet.2006.08.039
日期:2006.10
An efficient chiral N-heterocyclic carbene ligand for the Ir-catalyzed asymmetric hydrogenation of largely unfunctionalized tri-substituted olefins has been developed. The Ir-NHC-thiazole catalyst is able to reduce a large variety of substrates with excellent conversions and good enantioselectivities with ee's ranging from 34% to 90%, depending on the geometry around the double bond of the substrates. (c) 2006 Elsevier Ltd. All rights reserved.