ASYMMETRIC CYCLOPROPANATION CATALYZED BY CATIONIC BIS(OXAZOLINE)-CU-II COMPLEXES EXCHANGED INTO CLAYS

Citation
Jm. Fraile et al., ASYMMETRIC CYCLOPROPANATION CATALYZED BY CATIONIC BIS(OXAZOLINE)-CU-II COMPLEXES EXCHANGED INTO CLAYS, Tetrahedron : asymmetry, 8(13), 1997, pp. 2089-2092
Citations number
32
Categorie Soggetti
Chemistry Inorganic & Nuclear","Chemistry Inorganic & Nuclear","Chemistry Physical
Journal title
ISSN journal
09574166
Volume
8
Issue
13
Year of publication
1997
Pages
2089 - 2092
Database
ISI
SICI code
0957-4166(1997)8:13<2089:ACCBCB>2.0.ZU;2-N
Abstract
Several clays, exchanged with cationic bis(oxazoline)-Cu-II complexes, have been tested as catalysts in the benchmark cyclopropanation react ion of styrene with ethyl diazoacetate. Either the catalytic activity or the enantioselectivity are improved with regard to the same complex es when used in homogenous phase. The solvent used to carry out the ca tionic exchange has a decisive influence on the enantioselectivity and the same is true with regard to the solvent used in the homogeneous r eaction. The clay-catalysed reactions lead to an increase in the amoun t of cis-cyclopropanes. These catalysts are recoverable and retain mos t of their catalytic activity. (C) 1997 Elsevier Science Ltd.