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Volumn 68, Issue 1, 2003, Pages 27-34

Enantioselective synthesis of α-amino acids from N-tosyloxy β-lactams derived from β-keto esters

Author keywords

[No Author keywords available]

Indexed keywords

NUCLEOPHILIC ADDITION;

EID: 0037427981     PISSN: 00223263     EISSN: None     Source Type: Journal    
DOI: 10.1021/jo0162437     Document Type: Article
Times cited : (32)

References (52)
  • 1
    • 0002102562 scopus 로고
    • Georg, G. I., Ed.; VCH Publishers: New York
    • Ojima, I. In The Organic Chemistry of β-Lactams; Georg, G. I., Ed.; VCH Publishers: New York, 1993; pp 197-255.
    • (1993) The Organic Chemistry of β-Lactams , pp. 197-255
    • Ojima, I.1
  • 2
    • 0002511289 scopus 로고
    • JAI Press Inc.: Greenwich, CT
    • Ojima, I. In Advances in Asymmetric Synthesis; JAI Press Inc.: Greenwich, CT, 1995; Vol. 1, pp 95-146.
    • (1995) Advances in Asymmetric Synthesis , vol.1 , pp. 95-146
    • Ojima, I.1
  • 25
    • 0002441558 scopus 로고
    • Georg G.I., Ed.; VCH Publishers: New York
    • For a discussion of various approaches to functionalize each position of the 2-azetidinone ring, including other approaches to α-keto β-lactams, see Wild, H. In The Organic Chemistry of β-Lactams; Georg, G. I., Ed.; VCH Publishers: New York, 1993; pp 49-119.
    • (1993) The Organic Chemistry of β-Lactams , pp. 49-119
    • Wild, H.1
  • 49
    • 0035874733 scopus 로고    scopus 로고
    • It is interesting to note that Palomo and co-workers have reported that the condensation of ent-NCA 32b with 2 equiv of -leucine benzyl ester under several sets of conditions produced varying mixtures of the corresponding diastereomers due to some epimerization of the NCA during the reaction. The apparent difference in outcomes for the results of the Palomo laboratories and our own in the condensation of the two epimers of NCA 32b with branched amines is not completely clear. However, it is possible that these differences could be due to any of the following causes: (1) our use of 1.1 equiv of amine as opposed to 2.0 equiv as in the report from the Palomo group, (2) subtle differences in reactivity of (S)-α-methylbenzylamine and (S/-leucine benzyl ester, (3) given that opposite enantiomers of 32b were used, a matched vs a mismathced effect for the NCA and amine nucleophile/base could have been the causative factor. These results further reinforce the observations previously reported suggesting the importance of the reaction conditions in the condensation NCAs with amine nucleophiles (see refs 33 and 34 for more discussion and examples). For the original report from the Palomo laboratories using ent-NCA 32b, please see Palomo, C.; Oiarbide, M.; Landa, A.; Esnal, A.; Linden, A. J. Org. Chem. 2001, 66, 4180-4186
    • (2001) J. Org. Chem. , vol.66 , pp. 4180-4186
    • Palomo, C.1    Oiarbide, M.2    Landa, A.3    Esnal, A.4    Linden, A.5


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.