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Volumn 129, Issue 18, 2007, Pages 6050-6055

Practical synthesis of enantiomerically pure β2-amino acids via proline-catalyzed diastereoselective aminomethylation of aldehydes

Author keywords

[No Author keywords available]

Indexed keywords

ALDEHYDES; CATALYSIS; COLUMN CHROMATOGRAPHY; CRYSTALLIZATION; ENANTIOMERS; METHYLATION; SUBSTITUTION REACTIONS; SYNTHESIS (CHEMICAL);

EID: 34248562082     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja070063i     Document Type: Article
Times cited : (69)

References (114)
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    • 2nd ed, Juaristi, E, Soloshonok, V, Ed, Wiley-VCH: New-York
    • (b) Enantioselective Synthesis of β-Amino Acids, 2nd ed.; Juaristi, E., Soloshonok, V., Ed.; Wiley-VCH: New-York, 2005.
    • (2005) Enantioselective Synthesis of β-Amino Acids
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    • Examples of catalytic methods: (a) Duursma, A.; Minnaard, A. J.; Feringa, B. L. J. Am. Chem. Soc. 2003, 125, 3700.
    • Examples of catalytic methods: (a) Duursma, A.; Minnaard, A. J.; Feringa, B. L. J. Am. Chem. Soc. 2003, 125, 3700.
  • 28
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    • Cordova and co-workers independently reported similar Mannich reactions: (a) Ibrahem, I.; Dziedzic, P.; Cordova, A. Synthesis 2006, 4060.
    • Cordova and co-workers independently reported similar Mannich reactions: (a) Ibrahem, I.; Dziedzic, P.; Cordova, A. Synthesis 2006, 4060.
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    • Early studies: (a) List, B. J. Am. Chem. Soc. 2000, 122, 9336.
    • Early studies: (a) List, B. J. Am. Chem. Soc. 2000, 122, 9336.
  • 40
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    • Recent examples: (a) Mitsumori, S.; Zhang, H.; Ha-Yeon Cheong, P.; Houk, K. N.; Tanaka, F.; Barbas, C. F., III. J. Am. Chem. Soc. 2006, 128, 1040.
    • Recent examples: (a) Mitsumori, S.; Zhang, H.; Ha-Yeon Cheong, P.; Houk, K. N.; Tanaka, F.; Barbas, C. F., III. J. Am. Chem. Soc. 2006, 128, 1040.
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    • There are two possible sources of N-benzyl-α- methylbenzylamine in the reaction mixture: hydrolysis of the iminium by residual water, and retro-Michael reaction of the Mannich adduct as shown in Scheme 2.
    • There are two possible sources of N-benzyl-α- methylbenzylamine in the reaction mixture: hydrolysis of the iminium by residual water, and retro-Michael reaction of the Mannich adduct as shown in Scheme 2.
  • 59
    • 23944480330 scopus 로고    scopus 로고
    • For examples of epimerization of α-substituted aldehydes: (a) Chi, Y, Peelen, T. J, Gellman, S. H. Org. Lett. 2005, 7, 3469
    • For examples of epimerization of α-substituted aldehydes: (a) Chi, Y.; Peelen, T. J.; Gellman, S. H. Org. Lett. 2005, 7, 3469.
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    • Although the Mannich reaction at room temperature with L-proline as catalyst can give dr comparable to that at -25°C, epimerization leads to poor reproducibility of Mannich reaction product diastereoselectivity at this temperature
    • Although the Mannich reaction at room temperature with L-proline as catalyst can give dr comparable to that at -25°C, epimerization leads to poor reproducibility of Mannich reaction product diastereoselectivity at this temperature.
  • 63
    • 34248509630 scopus 로고    scopus 로고
    • A three-component Mannich reaction using pentanal, formaldehyde and (S)-N-benzyl-α-methylbenzylamine in the presence of L-proline as catalyst gave the desired Mannich product in 60% yield with ∼80:20 dr, along with side product α,β-unsaturated aldehyde (Scheme 2).
    • A three-component Mannich reaction using pentanal, formaldehyde and (S)-N-benzyl-α-methylbenzylamine in the presence of L-proline as catalyst gave the desired Mannich product in 60% yield with ∼80:20 dr, along with side product α,β-unsaturated aldehyde (Scheme 2).
  • 64
    • 34248552439 scopus 로고    scopus 로고
    • 1H NMR (Supporting Information) is necessary.
    • 1H NMR (Supporting Information) is necessary.
  • 65
    • 34248538913 scopus 로고    scopus 로고
    • The aldehyde starting material is more reactive towards the amine catalyst than is the Mannich product (α-substituted aldehyde) because of steric effects
    • The aldehyde starting material is more reactive towards the amine catalyst than is the Mannich product (α-substituted aldehyde) because of steric effects.
  • 66
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    • For examples of non-covalent interactions in catalysis: (a) Tian, S, Chen, Y, Hang, J, Tang, L, McDaid, P, Deng, L. Acc. Chem. Res. 2004, 37, 621
    • For examples of non-covalent interactions in catalysis: (a) Tian, S.; Chen, Y.; Hang, J.; Tang, L.; McDaid, P.; Deng, L. Acc. Chem. Res. 2004, 37, 621.
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    • For discussion of double diastereoselectivity in reactions with matched/ mismatched chirality of reaction components, see: Masamune, S.; Choy, W.; Petersen, J. S.; Sita, L. R. Angew. Chem., Int. Ed. Engl. 1985, 24, 1.
    • For discussion of "double diastereoselectivity" in reactions with matched/ mismatched chirality of reaction components, see: Masamune, S.; Choy, W.; Petersen, J. S.; Sita, L. R. Angew. Chem., Int. Ed. Engl. 1985, 24, 1.
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    • For a recent summary of the use of diaryl prolinol ethers as asymmetric catalysts
    • For a recent summary of the use of diaryl prolinol ethers as asymmetric catalysts: Palomo, C.; Mielgo, A. Angew. Chem., Int. Ed. 2006, 45, 7876.
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    • Palomo, C.1    Mielgo, A.2
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    • For recent examples using diaryl prolinol ethers as asymmetric catalysts: a
    • For recent examples using diaryl prolinol ethers as asymmetric catalysts: (a) Brandau, S.; Maerten, E.; Jørgensen, K. A. J. Am. Chem. Soc. 2006, 128, 14986.
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    • Brandau, S.1    Maerten, E.2    Jørgensen, K.A.3
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    • Ref 8 and 14b
    • (l) Ref 8 and 14b.
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    • The aldehyde prepared from PCC oxidation was filtered through a silica pad; the filtrate was collected, concentrated, and subjected to Mannich reaction without further purification
    • The aldehyde prepared from PCC oxidation was filtered through a silica pad; the filtrate was collected, concentrated, and subjected to Mannich reaction without further purification.
  • 98
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    • We did not attempt to isolate the aldehyde product or directly oxidize it to carboxylic acid, because it is easier to separate the major diastereomer as the alcohol form. The aldehyde intermediates are subject to epimerization and side reactions such as retro-Michael reaction
    • We did not attempt to isolate the aldehyde product or directly oxidize it to carboxylic acid, because it is easier to separate the major diastereomer as the alcohol form. The aldehyde intermediates are subject to epimerization and side reactions such as retro-Michael reaction.
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    • Oxidation of chiral α-substituted aldehydes and alcohols to carboxylic acids without epimerization: (a) Rangaishenvi, M. V.; Singaram, B.; Brown, H. C. J. Org. Chem. 1991, 56, 3286.
    • Oxidation of chiral α-substituted aldehydes and alcohols to carboxylic acids without epimerization: (a) Rangaishenvi, M. V.; Singaram, B.; Brown, H. C. J. Org. Chem. 1991, 56, 3286.
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    • See also refs 8, 14a,b
    • (c) See also refs 8, 14a,b.
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    • About 1.5 equiv aldehyde was used. Excess starting aldehyde reactant can be recycled (via the corresponding alcohol) after the Mannich reaction/ reduction sequence.
    • About 1.5 equiv aldehyde was used. Excess starting aldehyde reactant can be recycled (via the corresponding alcohol) after the Mannich reaction/ reduction sequence.
  • 109
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    • Concentration of LiCl refers to room temperature concentration. At - 25 °C, LiCl partially precipitates.
    • Concentration of LiCl refers to room temperature concentration. At - 25 °C, LiCl partially precipitates.
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    • See Supporting Information for details regarding use of 1H NMR to monitor the reaction
    • 1H NMR to monitor the reaction.
  • 111
    • 34248526479 scopus 로고    scopus 로고
    • Proline has poor solubility in DMF and is not completely dissolved even after it is stirred overnight. The Mannich reaction time can vary from a few to 24 h partially because of the limited solubility of proline
    • Proline has poor solubility in DMF and is not completely dissolved even after it is stirred overnight. The Mannich reaction time can vary from a few to 24 h partially because of the limited solubility of proline.
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    • It is important to remove DMF completely to achieve efficient crystallization. When using column chromatography for purification, a small amount residual DMF does not affect the purification
    • It is important to remove DMF completely to achieve efficient crystallization. When using column chromatography for purification, a small amount residual DMF does not affect the purification.
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    • Recrystallization may be necessary if the crystals contain the minor diastereomer at this point
    • Recrystallization may be necessary if the crystals contain the minor diastereomer at this point.
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    • 7).
    • 7).


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.