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Volumn 696, Issue 9, 2011, Pages 1760-1767

Unusual deactivation in the asymmetric hydrogenation of itaconic acid

Author keywords

Catalyst deactivation; Enantioselective hydrogenation; Homogeneous catalysis; Itaconic acid; Rhodium alkyl complex

Indexed keywords

ASYMMETRIC HYDROGENATION; ENANTIOSELECTIVE HYDROGENATION; HOMOGENEOUS CATALYSIS; ITACONIC ACID; NMR DATA; NMR SIGNALS; PH VALUE; REACTION TIME; SUBSTRATE COMPLEXES; SUBSTRATE CONCENTRATIONS;

EID: 79954993724     PISSN: 0022328X     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.jorganchem.2010.12.020     Document Type: Article
Times cited : (10)

References (39)
  • 19
  • 21
    • 79955021895 scopus 로고    scopus 로고
    • The X-ray structure of the complex surprisingly revealed that the substrate is not coordinated via the C-C double bond and one carboxylate oxygen, but instead via the two carboxylate oxygens and the quaternary carbon [C(2)] atom. Formally the acidic functions of the substrate had been completely deprotonated and the methylene group had been already converted into a methyl group via H-transfer. The tetrafluoroborate anion was no longer present in the crystal as the counterion. Thus, the complex represents a neutral Rh(III) alkyl complex, compare Reference [3]
    • The X-ray structure of the complex surprisingly revealed that the substrate is not coordinated via the C-C double bond and one carboxylate oxygen, but instead via the two carboxylate oxygens and the quaternary carbon [C(2)] atom. Formally the acidic functions of the substrate had been completely deprotonated and the methylene group had been already converted into a methyl group via H-transfer. The tetrafluoroborate anion was no longer present in the crystal as the counterion. Thus, the complex represents a neutral Rh(III) alkyl complex, compare Reference [3].
  • 22
    • 79955014779 scopus 로고    scopus 로고
    • 2 group we use methyl succinate instead of itaconate. A reasonable mechanism for the formation of this complex is proposed in Ref. [3]
    • 2 group we use methyl succinate instead of itaconate. A reasonable mechanism for the formation of this complex is proposed in Ref. [3].
  • 24
    • 0001352616 scopus 로고
    • An expedient method for preparative procedures in an inert atmosphere
    • S. Herzog, J. Dehnert, and K. Lühder An expedient method for preparative procedures in an inert atmosphere H.B. Jonassen, A. Weissberger, Technique Of Inorganic Chemistry vol. VII 1968 John Wiley & Sons New York 119 149
    • (1968) Technique of Inorganic Chemistry , vol.7 , pp. 119-149
    • Herzog, S.1    Dehnert, J.2    Lühder, K.3
  • 27
    • 79955028030 scopus 로고    scopus 로고
    • Color fading, a phenomenon also reported by Brown et al. [16] was over in a few minutes: the NMR spectra were recorded after complete color change
    • Color fading, a phenomenon also reported by Brown et al. [16] was over in a few minutes: the NMR spectra were recorded after complete color change.
  • 28
    • 79955012150 scopus 로고    scopus 로고
    • Due to the limited solubility of the substrate in methanol higher substrate-to-catalyst ratios could not be investigated. In an experiment were a 100-fold substrate excess was used, about half of the substrate, which was dissolved by heating, recrystallized immediately with cooling of the sample
    • Due to the limited solubility of the substrate in methanol higher substrate-to-catalyst ratios could not be investigated. In an experiment were a 100-fold substrate excess was used, about half of the substrate, which was dissolved by heating, recrystallized immediately with cooling of the sample.
  • 32
    • 79955002106 scopus 로고    scopus 로고
    • This effect may be caused by an increasing stability of the aryl-bridged dimers with decreasing temperature. A further possible explanation is the disturbance of the thermodynamic equilibrium between the solvent complex and the above mentioned dimers due to the fact that the observed catalyst-substrate complex is mainly formed from the solvent complex
    • This effect may be caused by an increasing stability of the aryl-bridged dimers with decreasing temperature. A further possible explanation is the disturbance of the thermodynamic equilibrium between the solvent complex and the above mentioned dimers due to the fact that the observed catalyst-substrate complex is mainly formed from the solvent complex.
  • 37
    • 79955006877 scopus 로고    scopus 로고
    • 3 is a strong base, we assume that an equimolar solution of the two species should be neutral
    • 3 is a strong base, we assume that an equimolar solution of the two species should be neutral.
  • 38
    • 79954997280 scopus 로고    scopus 로고
    • 13C measurements
    • 13C measurements.
  • 39
    • 79954987299 scopus 로고    scopus 로고
    • 2 group
    • 2 group.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.