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Volumn 128, Issue 51, 2006, Pages 17063-17073

On the mechanism of an asymmetric α,β-unsaturated carboxylic acid hydrogenation: Application to the synthesis of a PGD2 receptor antagonist

Author keywords

[No Author keywords available]

Indexed keywords

ASYMMETRIC HYDROGENATION CATALYSTS; CHIRAL LIGANDS; LOW HYDROGEN PRESSURES; RUTHENIUM COMPLEXES;

EID: 33845920911     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja0623358     Document Type: Article
Times cited : (30)

References (69)
  • 3
    • 33845938478 scopus 로고    scopus 로고
    • Blaser, H.-U.; Spindler, F.; Thommen, M.; Blaser, H. U.; F. S., Thommen, M. Industrial Applications. In Handbook of Homogeneous Hydrogenation; de Vries, J.G., Elsevier, C. J., Eds.; Wiley-VCH: Weinheim, Germany, 2006.
    • Blaser, H.-U.; Spindler, F.; Thommen, M.; Blaser, H. U.; F. S., Thommen, M. Industrial Applications. In Handbook of Homogeneous Hydrogenation; de Vries, J.G., Elsevier, C. J., Eds.; Wiley-VCH: Weinheim, Germany, 2006.
  • 15
    • 33845945109 scopus 로고    scopus 로고
    • Methods have been reported for setting the chiral center in 2
    • Methods have been reported for setting the chiral center in 2. See refs 16-18.
    • See refs , pp. 16-18
  • 19
    • 0025778593 scopus 로고
    • For a diastereoselective heterogeneous hydrogenation of an indole α,β-unsaturated ester, see
    • For a diastereoselective heterogeneous hydrogenation of an indole α,β-unsaturated ester, see: Beard, R. L.; Meyers, A. I. J. Org. Chem. 1991, 56, 2091-2096.
    • (1991) J. Org. Chem , vol.56 , pp. 2091-2096
    • Beard, R.L.1    Meyers, A.I.2
  • 20
    • 13344287589 scopus 로고
    • For a diastereoselective homogeneous exocyclic α,β-unsaturated ester, see
    • For a diastereoselective homogeneous exocyclic α,β-unsaturated ester, see: Ohba, M.; Haneishi, T.; Fujii, T. Heterocycles 1994, 38, 2253-2265.
    • (1994) Heterocycles , vol.38 , pp. 2253-2265
    • Ohba, M.1    Haneishi, T.2    Fujii, T.3
  • 21
    • 33845963321 scopus 로고    scopus 로고
    • For examples of asymmetric exocyclic dehydroamino acid hydrogenations, see refs 22-25
    • For examples of asymmetric exocyclic dehydroamino acid hydrogenations, see refs 22-25.
  • 26
    • 33845941391 scopus 로고    scopus 로고
    • Manuscript in preparation
    • Humphrey, G. R.; et al. Manuscript in preparation.
    • Humphrey, G.R.1
  • 27
    • 33845953375 scopus 로고    scopus 로고
    • 4 to give the corresponding chiral ester in 88% ee.
    • 4 to give the corresponding chiral ester in 88% ee.
  • 30
    • 33845963597 scopus 로고    scopus 로고
    • Compound 1 exhibited poor solubility in most solvents at room temperature. A detailed list of solubilities can be found in the Supporting Information.
    • Compound 1 exhibited poor solubility in most solvents at room temperature. A detailed list of solubilities can be found in the Supporting Information.
  • 31
    • 33845923858 scopus 로고    scopus 로고
    • Synthesis of 1-Br-E employing the chemistry used to prepare 1-E results in 10-30% debromination.
    • Synthesis of 1-Br-E employing the chemistry used to prepare 1-E results in 10-30% debromination.
  • 33
    • 33845930797 scopus 로고    scopus 로고
    • For reviews on the application of BINAP and its derivatives to asymmetric catalysis, see refs 34-36.
    • For reviews on the application of BINAP and its derivatives to asymmetric catalysis, see refs 34-36.
  • 37
    • 33845923856 scopus 로고    scopus 로고
    • This is supported by the NMR spectroscopic observation that thermolysis of 3 in the presence of stoichiometric 1-E liberates p-cymene over ca. 6 min
    • This is supported by the NMR spectroscopic observation that thermolysis of 3 in the presence of stoichiometric 1-E liberates p-cymene over ca. 6 min.
  • 38
    • 33845947911 scopus 로고    scopus 로고
    • Assay yields were determined by preparing a known concentration of analytically pure 2 and comparing the UV response (HPLC) of this solution against that of a hydrogenation reaction solution.
    • Assay yields were determined by preparing a known concentration of analytically pure 2 and comparing the UV response (HPLC) of this solution against that of a hydrogenation reaction solution.
  • 39
    • 33845933347 scopus 로고    scopus 로고
    • In all cases, percent conversions refer to HPLC area percent measured at 215 nm. Conversion, area product, area product, area starting material
    • In all cases, percent conversions refer to HPLC area percent measured at 215 nm. Conversion = (area product)/(area product + area starting material).
  • 40
    • 33845932541 scopus 로고    scopus 로고
    • Heating a methanol solution of 1-E·TMG in the absence of catalyst for 12 h at 50 °C does not produce 1-Endo·TMG.
    • Heating a methanol solution of 1-E·TMG in the absence of catalyst for 12 h at 50 °C does not produce 1-Endo·TMG.
  • 42
    • 33845928441 scopus 로고    scopus 로고
    • Photolysis of 1-E·TMG in CD3OD does not incorporate deuterium into either 1-E·TMG or 1-Z·TMG.
    • Photolysis of 1-E·TMG in CD3OD does not incorporate deuterium into either 1-E·TMG or 1-Z·TMG.
  • 48
    • 33845953065 scopus 로고    scopus 로고
    • Solutions of pure 1-Endo in the presence of catalyst isomerize to generate an equilibrium mixture with 1-E. As such, we opted to start with the equilibrated mixture instead of pure 1-Endo to ensure that the starting concentration of 1-Endo was constant between experiments. Consistent with results from Figure 7, the high-pressure syringe pump addition of catalyst to a solution of 1-Endo at 100 psig H2 and 50 °C produced 2 in 92% ee.
    • Solutions of pure 1-Endo in the presence of catalyst isomerize to generate an equilibrium mixture with 1-E. As such, we opted to start with the equilibrated mixture instead of pure 1-Endo to ensure that the starting concentration of 1-Endo was constant between experiments. Consistent with results from Figure 7, the high-pressure syringe pump addition of catalyst to a solution of 1-Endo at 100 psig H2 and 50 °C produced 2 in 92% ee.
  • 49
    • 33845925753 scopus 로고    scopus 로고
    • At 515 psi, the reaction rate was sufficiently fast that complete consumption of 1-Endo isomer and some of the 1-E isomer had occurred at 20 area, conversion. The point at 10 area, conversion at 515 psi is calculated by removing the contribution from 1-E
    • At 515 psi, the reaction rate was sufficiently fast that complete consumption of 1-Endo isomer and some of the 1-E isomer had occurred at 20 area % conversion. The point at 10 area % conversion at 515 psi is calculated by removing the contribution from 1-E.
  • 50
    • 33845929977 scopus 로고    scopus 로고
    • This information can be found in the Supporting Information
    • This information can be found in the Supporting Information.
  • 51
    • 33845924367 scopus 로고    scopus 로고
    • An identical result is obtained when the relative ratios of the R and S enantiomers are used in place of %ee
    • An identical result is obtained when the relative ratios of the R and S enantiomers are used in place of %ee.
  • 52
    • 33845942693 scopus 로고    scopus 로고
    • Qualitatively, the Z isomer was less reactive than the E isomer toward hydrogenation with 3.
    • Qualitatively, the Z isomer was less reactive than the E isomer toward hydrogenation with 3.
  • 60
    • 33845960459 scopus 로고    scopus 로고
    • 2, was employed because catalyst 3 does not react with the free acid. It is thought that base is required to facilitate cymene displacement and generation of the active catalyst.
    • 2, was employed because catalyst 3 does not react with the free acid. It is thought that base is required to facilitate cymene displacement and generation of the active catalyst.
  • 61
    • 33845930529 scopus 로고    scopus 로고
    • 2 with and without TMG was 92-93.%.
    • 2 with and without TMG was 92-93.%.
  • 63
    • 33845934425 scopus 로고    scopus 로고
    • A similar observation was noted by Chan and co-workers in the hydrogenation of a naproxen precursor with a ruthenium catalyst under basic conditions. See ref 64
    • A similar observation was noted by Chan and co-workers in the hydrogenation of a naproxen precursor with a ruthenium catalyst under basic conditions. See ref 64.
  • 65
    • 33845964114 scopus 로고    scopus 로고
    • The substrate is assumed to be bound to the metal via the carboxylate linkage. This is supported by literature reports (see ref 57 and 66) and the observation that the methyl ester derivative of 1 is not hydrogenated by 3
    • The substrate is assumed to be bound to the metal via the carboxylate linkage. This is supported by literature reports (see ref 57 and 66) and the observation that the methyl ester derivative of 1 is not hydrogenated by 3.
  • 67
    • 33845961481 scopus 로고    scopus 로고
    • A reviewer is acknowledged tor suggesting this two-point binding mechanism to rationalize the higher enantioselectivity
    • A reviewer is acknowledged tor suggesting this two-point binding mechanism to rationalize the higher enantioselectivity.
  • 69
    • 33845952583 scopus 로고    scopus 로고
    • In the absence of hydrogen, methanolic solutions of 1-E·TMG and 3 were found to liberate small quantities of the catalyst poisons dimethylamine and ammonia over 24 h GC analysis, In order to maximize catalyst turnover, solutions of the catalyst 3 were added immediately prior to hydrogen addition
    • In the absence of hydrogen, methanolic solutions of 1-E·TMG and 3 were found to liberate small quantities of the catalyst poisons dimethylamine and ammonia over 24 h (GC analysis). In order to maximize catalyst turnover, solutions of the catalyst 3 were added immediately prior to hydrogen addition.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.