Diastereoselective routes to [amino{σ(P):η6-(ansa- phosphinite)benzene} chlororuthenium(II)] PF6 Salts: Kinetic versus thermodynamic preferences
Weber I, Heinemann FW, Bauer W, Superchi S, Zahl A, Richter D, Zenneck U (2008)
Publication Type: Journal article, Original article
Publication year: 2008
Journal
Original Authors: Weber I., Heinemann F.W., Bauery W., Superchi S., Zahl A., Richter D., Zenneck U.
Publisher: American Chemical Society
Book Volume: 27
Pages Range: 4116-4125
Journal Issue: 16
DOI: 10.1021/om701257m
Abstract
A novel chiral phosphinite derivative was designed as a ligand for Ru ions to give access to new enantiomerically pure or diastereomerically enriched [{σ(P):η-(ansa-phosphinite) benzene}Ru(II) complexes. We are interested in this class of compounds as potential catalysts for enantioselective transfer hydrogenation of organic carbonyl compounds. The preparation of enantiopure (R)-[{σ(P): η-(ansaphosphinite)benzene /Ru(II)Cl] (6) was achieved in good yeld on the basis of (5)-mandelic acid. Four diastereomeric [{σ(P):η-(ansa-phosphinite)rjenzene}Ru(II)Cl(NH R)] complex PF salts were obtained from neutral 6 by nucleophilic substitution of a chloride ligand with primary amines. For aniline and p-fluoroaniline salts 7 and 8 a significant excess of the (5R)-diastereomers 7S and 8S was observed in the reaction mixtures as the kinetically preferred species, and 7S could be isolated as a pure diastereomer. No diastereoselectivity was observed in the reaction mixtures of (R)- and (5)-1-phenylethylamine salts 9 and 10 right after preparation. 7, 8, and 9 epimerize at the metal center. This leads to a loss of diastereoselectivity of 7S and 8S but enrichment of (R,R )-diastereomer 9R. Pure diastereomers 75, 9R, and 105 as well as a 1:1 diastereomeric mixture 8S/8R have been characterized structurally. The experimental setup allowed detailed insight into the specific X-ray crystallographic, CD, and NMR spectroscopic properties of defined stereoisomers of chiral Ru(II) complexes. The kinetic diastereose-lectivities of 75 and 85 are explained by a H-bond delivery effect, while pure diastereomer salt 9R is configuratively stable. © 2008 American Chemical Society.
Authors with CRIS profile
Immo Weber
Lehrstuhl für Anorganische und Metallorganische Chemie
Frank Wilhelm Heinemann
Lehrstuhl für Anorganische und Allgemeine Chemie
Walter Bauer
Lehrstuhl für Organische Chemie II
Achim Zahl
Lehrstuhl für Bioanorganische Chemie
Ulrich Zenneck
Naturwissenschaftliche Fakultät
Additional Organisation(s)
Interdisziplinäres Zentrum für Molekulare Materialien
Interdisziplinäres Zentrum Erlangen Catalysis Resource Center (ECRC)
Involved external institutions
Italy (IT)How to cite
APA:
Weber, I., Heinemann, F.W., Bauer, W., Superchi, S., Zahl, A., Richter, D., & Zenneck, U. (2008). Diastereoselective routes to [amino{σ(P):η6-(ansa- phosphinite)benzene} chlororuthenium(II)] PF6 Salts: Kinetic versus thermodynamic preferences. Organometallics, 27(16), 4116-4125. https://doi.org/10.1021/om701257m
MLA:
Weber, Immo, et al. "Diastereoselective routes to [amino{σ(P):η6-(ansa- phosphinite)benzene} chlororuthenium(II)] PF6 Salts: Kinetic versus thermodynamic preferences." Organometallics 27.16 (2008): 4116-4125.
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