The role played by the electronic properties and the steric features of bis(oxazoline) ligands in the Cu(I)-catalyzed cyclopropanation of styrene effected with ethyl diazoacetate was investigated. Two pairs of new bis(oxazolines) displaying flexible and atropisomeric 3,3′-bithiophene backbones were synthesized and structurally and electronically characterized. For the first time, the electrochemical oxidative potential was used as a reliable index of the electronic density on the nitrogen atom of the chelating groups of new and, for comparative purposes, of already known bis(oxazolines). The Cu(I) complexes of the new ligands were prepared, and their enantioselection ability and catalytic efficiency were tested. This investigation suggests that steric factors and catalyst geometrical features are clearly more important than any consideration of the electronic properties of the chiral ligands.

Steric and electronic tuning of chiral bis(oxazoline) ligands with 3,3'-bithiophene backbone / M. Benaglia, T. Benincori, P. Mussini, T. Pilati, S. Rizzo, F. Sannicolo'. - In: JOURNAL OF ORGANIC CHEMISTRY. - ISSN 0022-3263. - 70:19(2005), pp. 7488-7495.

Steric and electronic tuning of chiral bis(oxazoline) ligands with 3,3'-bithiophene backbone

M. Benaglia
Primo
;
P. Mussini;F. Sannicolo'
Ultimo
2005

Abstract

The role played by the electronic properties and the steric features of bis(oxazoline) ligands in the Cu(I)-catalyzed cyclopropanation of styrene effected with ethyl diazoacetate was investigated. Two pairs of new bis(oxazolines) displaying flexible and atropisomeric 3,3′-bithiophene backbones were synthesized and structurally and electronically characterized. For the first time, the electrochemical oxidative potential was used as a reliable index of the electronic density on the nitrogen atom of the chelating groups of new and, for comparative purposes, of already known bis(oxazolines). The Cu(I) complexes of the new ligands were prepared, and their enantioselection ability and catalytic efficiency were tested. This investigation suggests that steric factors and catalyst geometrical features are clearly more important than any consideration of the electronic properties of the chiral ligands.
Settore CHIM/06 - Chimica Organica
Settore CHIM/01 - Chimica Analitica
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/14870
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