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Volumn 125, Issue 43, 2003, Pages 13012-13013

Asymmetric Cyclization via Memory of Chirality: A Concise Access to Cyclic Amino Acids with a Quaternary Stereocenter

Author keywords

[No Author keywords available]

Indexed keywords

AMINO ACID;

EID: 0142245598     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja0378299     Document Type: Article
Times cited : (84)

References (26)
  • 22
    • 0142150733 scopus 로고    scopus 로고
    • note
    • For example, α-methylation of N-Boc-N-methyl phenylalanine derivatives proceeds in up to 82% ee, while that of the corresponding N-formyl-N-methyl derivative gives a racemic product; see ref 8a.
  • 23
    • 0142212829 scopus 로고    scopus 로고
    • note
    • Whereas α-methylation of N-Boc-N-methoxymethyl(MOM)-phenylalanine, -tyrosine, and -valine derivatives proceeds in 81%, 79%, and 87% ee, respectively (ref 8b), α-allylation of N-Boc-N-MOM-alanine derivative proceeds in 33% ee (unpublished data). The low ee in the reaction of an alanine derivative seems to be at least in part due to rapid racemization of the chiral enolate intermediate during intermolecular alkylation. On the other hand, the loss of enantiomeric purity of the chiral enolate is minimized during rapid five-membered intramolecular alkylation, and it gives 10 with high enantiomeric excess.
  • 24
    • 0344778061 scopus 로고
    • The stable conformers A and B of 1 were generated by a molecular modeling search with AMBER* force field with the GB/SA solvation model for water using MacroModel V 6.0. The difference in potential energies between A and B is estimated to be 0.1 kcal/mol. A PM3 calculation with a polarized continuum model (water, ε = 78.4) also gave stable structures similar to A and B: (a) Still, W. C.; Tempczyk, A.; Hawley, R. C.; Hendrickson, T. J. Am. Chem. Soc. 1990, 112, 6127-6129; (b) J. Comput. Chem. 1991, 12, 620.
    • (1990) J. Am. Chem. Soc. , vol.112 , pp. 6127-6129
    • Still, W.C.1    Tempczyk, A.2    Hawley, R.C.3    Hendrickson, T.4
  • 25
    • 84986439485 scopus 로고
    • The stable conformers A and B of 1 were generated by a molecular modeling search with AMBER* force field with the GB/SA solvation model for water using MacroModel V 6.0. The difference in potential energies between A and B is estimated to be 0.1 kcal/mol. A PM3 calculation with a polarized continuum model (water, ε = 78.4) also gave stable structures similar to A and B: (a) Still, W. C.; Tempczyk, A.; Hawley, R. C.; Hendrickson, T. J. Am. Chem. Soc. 1990, 112, 6127-6129; (b) J. Comput. Chem. 1991, 12, 620.
    • (1991) J. Comput. Chem. , vol.12 , pp. 620


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.