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Coordination Studies on Supramolecular Chiral Ligands and Application in Asymmetric Hydroformylation
Author(s) -
Bellini Rosalba,
Reek Joost N. H.
Publication year - 2012
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201200225
Subject(s) - hydroformylation , denticity , chemistry , rhodium , hydride , ligand (biochemistry) , supramolecular chemistry , pyridine , coordination complex , selectivity , catalysis , stereochemistry , medicinal chemistry , combinatorial chemistry , crystallography , organic chemistry , crystal structure , hydrogen , metal , biochemistry , receptor
In this study we introduce a series of monodentate pyridine‐based ligands for which the phosphorus coordination mode to rhodium can be controlled by the binding of Zn II ‐templates to the pyridyl group. A series of monodentate phosphoroamidite and phosphite ligands have been prepared and studied under hydroformylation conditions by in situ high‐pressure NMR and IR techniques. These studies reveal the exclusive formation of rhodium hydride complexes in which the phosphorus atom of the ligand resides in an axial position, trans to the hydride, but only after addition of Zn II ‐template. In the absence of these templates the usual mono‐coordinated rhodium hydrido complexes are formed, with the phosphorus ligated in the equatorial plane, cis to the hydride. The catalytic performance of these complexes is evaluated in asymmetric hydroformylation of unfunctionalised internal alkenes in which the supramolecular change is reflected in higher activity and selectivity.