Azaarene cis-dihydrodiol-derived 2,2′-bipyridine ligands for asymmetric allylic oxidation and cyclopropanation
作者:Derek R. Boyd、Narain D. Sharma、Lenuta Sbircea、Deirdre Murphy、Tayeb Belhocine、John F. Malone、Stuart L. James、Christopher C. R. Allen、John T. G. Hamilton
DOI:10.1039/b814678k
日期:——
Biphenyl dioxygenase-catalysed cis-dihydroxylation of 2-chloroquinoline, 2-chloro-3-methylquinoline and 2-chloro-6-phenylpyridine substrates yielded the corresponding enantiopure cis-dihydrodiols; enantiopure 2,2â²-bipyridines, synthesised in four steps from 2-chloroquinoline, proved to be efficient chiral ligands in catalytic asymmetric allylic oxidation and cyclopropanation reactions of alkenes.
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
Enantioselective allylic oxidation catalyzed by chiral bisoxazoline-copper complexes
作者:Abha S. Gokhale、Alexander B.E. Minidis、Andreas Pfaltz
DOI:10.1016/0040-4039(95)00140-8
日期:1995.3
Copper(I) complexes prepared in situ from chiral bisoxazolines and Cu(I)OTf have been studied as catalysts for the allylic oxidation of cycloalkenes. Using 5 mol% of catalyst and tertbutyl perbenzoate as oxidant, optically active 2-cycloalkenyl benzoates were obtained in moderate to good yields. The highest enantiomeric excesses, 74% at 23 °C and up to 84% at lower temperatures, were observed for cyclopentene
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
Chemoenzymatic synthesis of chiral 2,2′-bipyridine ligands and their N-oxide derivatives: applications in the asymmetric aminolysis of epoxides and asymmetric allylation of aldehydes
作者:D. R. Boyd、N. D. Sharma、L. Sbircea、D. Murphy、J. F. Malone、S. L. James、C. C. R. Allen、J. T. G. Hamilton
DOI:10.1039/b919894f
日期:——
A series of enantiopure 2,2′-bipyridines have been synthesised from the corresponding cis-dihydrodiol metabolites of 2-chloroquinolines. Several of the resulting hydroxylated 2,2′-bipyridines were found to be useful chiral ligands for the asymmetric aminolysis of meso-epoxides leading to the formation of enantioenriched aminoalcohols (→84% ee). N-oxide and N,N′-dioxide derivatives of these 2,2′-bipyridines