Catalytic enantioselective rearrangement of meso-epoxides mediated by chiral lithium amides in the presence of excess cross-linked polymer-bound lithium amides
作者:Atsushi Seki、Masatoshi Asami
DOI:10.1016/s0040-4020(02)00371-x
日期:2002.6
Insoluble polymer-bound achiral lithium dialkylamides were prepared from the corresponding cross-linked polymer-bound amines and butyllithium. The polymer-bound achiral reagent was applied to a catalytic enantioselective rearrangement of meso-epoxides as an in situ regenerating agent of a chiral lithiumamide. The efficiency of the catalytic system was improved, and chiral allylic alcohol derivatives
New pinene-derived pyridines as bidentate chiral ligands
作者:Andrei V. Malkov、Angus J.P. Stewart-Liddon、Filip Teplý、Lukáš Kobr、Kenneth W. Muir、David Haigh、Pavel Kočovský
DOI:10.1016/j.tet.2008.02.045
日期:2008.4
β-pinene 11. A copper complex of the pyridine–oxazoline ligands 8a has been found to catalyze asymmetric allylic oxidation of cyclic olefins 36a–c with good conversion rates and acceptable enantioselectivity (≤67% ee). The imidazolium salt 10 has been identified as a precursor of the corresponding N,N′-unsymmetrical N-heterocyclic carbene ligand, whose complex with palladiumcatalyzed the intramolecular
Multiphase enantioselective Kharasch–Sosnovsky allylic oxidation based on neoteric solvents and copper complexes of ditopic ligands
作者:Luis Aldea、José I. García、José A. Mayoral
DOI:10.1039/c2dt30352c
日期:——
Recoverable multiphase enantioselective catalytic systems for the KharaschâSosnovsky oxidation of cycloalkenes with tert-butyl peroxybenzoate are described, based on the use of [BMIM][PF6] and a new solvent derived from glycerol as the catalyst reservoir phases, and chiral copper complexes with different ligands from the bis(oxazoline) family. The best results are obtained with the glycerol-derived solvent and a recently described azabisoxazoline-based ditopic ligand, allowing up to four uses of the catalytic phase with good results.
Enantioselective oxidation of olefins catalyzed by chiral copper bis(oxazolinyl)pyridine complexes: a reassessment
作者:Sandeep K. Ginotra、Vinod K. Singh
DOI:10.1016/j.tet.2006.01.093
日期:2006.4
Copper complexes of chiral tridentate pybox ligands synthesized using a modified procedure have been studied as catalysts for the enantioselective allylic oxidation of olefins. A variety of olefins have been used in this reaction. Using 5 mol% of a Cu(II) complex of the tridentate pybox ligand, phenylhydrazine, and tert-butyl perbenzoate as oxidant in acetone, optically active allylic benzoates were
Synthesis of New Chiral 2,2‘-Bipyridine Ligands and Their Application in Copper-Catalyzed Asymmetric Allylic Oxidation and Cyclopropanation
作者:Andrei V. Malkov、Daniele Pernazza、Mark Bell、Marco Bella、Antonio Massa、Filip Teplý、Premji Meghani、Pavel Kočovský
DOI:10.1021/jo034179i
日期:2003.6.1
rate (typicaly 30 min at room temperature) in allylic oxidation of cyclic olefins (52 --> 53). Copper-catalyzed cyclopropanation proceeded with < or =76% enantioselectivity and approximately 3:1 to 99:1 trans/cis-diastereoselectivity (54 --> 55 + 56). The level of the asymmetric induction is discussed in terms of the ligand architecture that controls the stereochemical environment of the coordinated