Chiral complexes of RhI containing binaphthalene-core P,S-heterobidentate ligands - Synthesis, characterization, and catalytic activity in asymmetric hydrogenation of α,β-unsaturated acids and esters

Serafino Gladiali, Fabrizia Grepioni, Serenella Medici, Antonio Zucca, Z. Berente, L. Kollár

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12 Citations (Scopus)

Abstract

The enantiopure complexes 3a and 3b [Rh(NBD)(P,S)]+BF4 - [P,S = (S)-2-(diphenylphosphanyl)-2′-(methylthio)-1,1′-binaphthalene (a); (S)-2-(diphenylphosphanyl)-2′-(isopropylthio)-1,1′-binaphthalene (b) have been prepared from [Rh(NBD)(THF)2]+BF4 - by reaction with a stoichiometric amount of the appropriate P,S-heterobidentate ligand. Single-crystal X-ray analysis of the S-methyl derivative shows that the seven-membered chelate ring is locked in a boat-like conformation with the methyl group in the equatorial position. Variable-temperature NMR measurements confirm that this conformation is maintained in solution and that the dynamic behaviour displayed by the complex is due to pseudo-rotation of the diolefin. Complexes 3 have been tested in the asymmetric hydrogenation of α,β-unsaturated acids and esters. Enantioselectivities of up to 60% ee have been recorded.

Original languageEnglish
Pages (from-to)556-561
Number of pages6
JournalEuropean Journal of Inorganic Chemistry
Issue number3
Publication statusPublished - Feb 2003

Fingerprint

Hydrogenation
Conformations
Catalyst activity
Esters
Alkadienes
Ligands
Acids
Enantioselectivity
X ray analysis
Boats
Nuclear magnetic resonance
Single crystals
Derivatives
Temperature

Keywords

  • Asymmetric catalysis
  • Hydrogenations
  • P ligands
  • Rhodium
  • S ligands

ASJC Scopus subject areas

  • Inorganic Chemistry

Cite this

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title = "Chiral complexes of RhI containing binaphthalene-core P,S-heterobidentate ligands - Synthesis, characterization, and catalytic activity in asymmetric hydrogenation of α,β-unsaturated acids and esters",
abstract = "The enantiopure complexes 3a and 3b [Rh(NBD)(P,S)]+BF4 - [P,S = (S)-2-(diphenylphosphanyl)-2′-(methylthio)-1,1′-binaphthalene (a); (S)-2-(diphenylphosphanyl)-2′-(isopropylthio)-1,1′-binaphthalene (b) have been prepared from [Rh(NBD)(THF)2]+BF4 - by reaction with a stoichiometric amount of the appropriate P,S-heterobidentate ligand. Single-crystal X-ray analysis of the S-methyl derivative shows that the seven-membered chelate ring is locked in a boat-like conformation with the methyl group in the equatorial position. Variable-temperature NMR measurements confirm that this conformation is maintained in solution and that the dynamic behaviour displayed by the complex is due to pseudo-rotation of the diolefin. Complexes 3 have been tested in the asymmetric hydrogenation of α,β-unsaturated acids and esters. Enantioselectivities of up to 60{\%} ee have been recorded.",
keywords = "Asymmetric catalysis, Hydrogenations, P ligands, Rhodium, S ligands",
author = "Serafino Gladiali and Fabrizia Grepioni and Serenella Medici and Antonio Zucca and Z. Berente and L. Koll{\'a}r",
year = "2003",
month = "2",
language = "English",
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journal = "Chemische Berichte",
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T1 - Chiral complexes of RhI containing binaphthalene-core P,S-heterobidentate ligands - Synthesis, characterization, and catalytic activity in asymmetric hydrogenation of α,β-unsaturated acids and esters

AU - Gladiali, Serafino

AU - Grepioni, Fabrizia

AU - Medici, Serenella

AU - Zucca, Antonio

AU - Berente, Z.

AU - Kollár, L.

PY - 2003/2

Y1 - 2003/2

N2 - The enantiopure complexes 3a and 3b [Rh(NBD)(P,S)]+BF4 - [P,S = (S)-2-(diphenylphosphanyl)-2′-(methylthio)-1,1′-binaphthalene (a); (S)-2-(diphenylphosphanyl)-2′-(isopropylthio)-1,1′-binaphthalene (b) have been prepared from [Rh(NBD)(THF)2]+BF4 - by reaction with a stoichiometric amount of the appropriate P,S-heterobidentate ligand. Single-crystal X-ray analysis of the S-methyl derivative shows that the seven-membered chelate ring is locked in a boat-like conformation with the methyl group in the equatorial position. Variable-temperature NMR measurements confirm that this conformation is maintained in solution and that the dynamic behaviour displayed by the complex is due to pseudo-rotation of the diolefin. Complexes 3 have been tested in the asymmetric hydrogenation of α,β-unsaturated acids and esters. Enantioselectivities of up to 60% ee have been recorded.

AB - The enantiopure complexes 3a and 3b [Rh(NBD)(P,S)]+BF4 - [P,S = (S)-2-(diphenylphosphanyl)-2′-(methylthio)-1,1′-binaphthalene (a); (S)-2-(diphenylphosphanyl)-2′-(isopropylthio)-1,1′-binaphthalene (b) have been prepared from [Rh(NBD)(THF)2]+BF4 - by reaction with a stoichiometric amount of the appropriate P,S-heterobidentate ligand. Single-crystal X-ray analysis of the S-methyl derivative shows that the seven-membered chelate ring is locked in a boat-like conformation with the methyl group in the equatorial position. Variable-temperature NMR measurements confirm that this conformation is maintained in solution and that the dynamic behaviour displayed by the complex is due to pseudo-rotation of the diolefin. Complexes 3 have been tested in the asymmetric hydrogenation of α,β-unsaturated acids and esters. Enantioselectivities of up to 60% ee have been recorded.

KW - Asymmetric catalysis

KW - Hydrogenations

KW - P ligands

KW - Rhodium

KW - S ligands

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