Dedicated to Professor Cesare Gennari on the occasion of his 60th birthday
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Full Paper
SupraBox: Chiral Supramolecular Oxazoline Ligands†
Article first published online: 10 JUL 2012
DOI: 10.1002/ejoc.201200516
Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Additional Information
How to Cite
Durini, M., Russotto, E., Pignataro, L., Reiser, O. and Piarulli, U. (2012), SupraBox: Chiral Supramolecular Oxazoline Ligands . Eur. J. Org. Chem., 2012: 5451–5461. doi: 10.1002/ejoc.201200516
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Publication History
- Issue published online: 18 SEP 2012
- Article first published online: 10 JUL 2012
- Manuscript Received: 19 APR 2012
Keywords:
- Supramolecular chemistry;
- Self-assembly;
- N ligands;
- Asymmetric catalysis;
- Acylation
Abstract
A new class of oxazoline ligands, named SupraBox, was studied. These ligands possess an additional urea functionality to generate supramolecular bidentate ligands in transition-metal complexes, by the establishment of hydrogen bonds between the urea N-hydrogens of one ligand and the carbonyl oxygen of a second one. A library of 16 SupraBox ligands was prepared using 5 differently substituted oxazoline nuclei, 4 linkers and 3 different urea substituents. The formation of copper(II) and palladium(II) complexes was investigated by MS, UV/Vis and 1H-NMR spectroscopy. The SupraBox library was screened in the copper-catalyzed asymmetric benzoylation of vic-diols. Good selectivities were obtained in the kinetic resolution of racemic hydrobenzoin [up to 86 % ee and selectivity (s) = 28] and in the desymmetrization of meso-hydrobenzoin (up to 88 % ee).