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Volumn 9, Issue 12, 2007, Pages 2365-2368

Stereoselective lodocyclization of (S)-allylalanine derivatives: γ-lactone vs cyclic carbamate formation

Author keywords

[No Author keywords available]

Indexed keywords

ALANINE; CARBAMIC ACID DERIVATIVE; DRUG DERIVATIVE; LACTONE;

EID: 34250797917     PISSN: 15237060     EISSN: None     Source Type: Journal    
DOI: 10.1021/ol070764k     Document Type: Article
Times cited : (35)

References (50)
  • 40
    • 34250809891 scopus 로고    scopus 로고
    • 2 afforded comparable reactivity as far as reaction rates and stereoselectivity but with significantly lower chemical yields (59%).
    • 2 afforded comparable reactivity as far as reaction rates and stereoselectivity but with significantly lower chemical yields (59%).
  • 41
    • 0034742945 scopus 로고    scopus 로고
    • When the unprotected substrate (S)-l was used, complex reaction mixtures were obtained where complete substrate disappearance and no significant amount of iodocyclization products were detected. Reactions between iodine and and amines have been reported to afford N-iodination, formation of molecular complexes, and in some cases, unusual oxidation processes, and therefore N-protection is required. See: Jones, A. D.; Knight, D. W.; Hibbs, D. E. J. Chem. Soc., Perkin Trans. 1 2001, 1182-1203 and refs therein.
    • When the unprotected substrate (S)-l was used, complex reaction mixtures were obtained where complete substrate disappearance and no significant amount of iodocyclization products were detected. Reactions between iodine and and amines have been reported to afford N-iodination, formation of molecular complexes, and in some cases, unusual oxidation processes, and therefore N-protection is required. See: Jones, A. D.; Knight, D. W.; Hibbs, D. E. J. Chem. Soc., Perkin Trans. 1 2001, 1182-1203 and refs therein.
  • 42
    • 34250871327 scopus 로고    scopus 로고
    • 2 appears as an ABX system at 2.42 and 2.71 ppm in 4a, whereas in anti-4b it is at 1.96 and 3.12 ppm, respectively.
    • 2 appears as an ABX system at 2.42 and 2.71 ppm in 4a, whereas in anti-4b it is at 1.96 and 3.12 ppm, respectively.
  • 45
    • 34250838336 scopus 로고    scopus 로고
    • Although the diastereomeric mixtures 4a/4b and 6a/6b are separable through radial chromatography, the isomers 5a/5b remain unseparable
    • Although the diastereomeric mixtures 4a/4b and 6a/6b are separable through radial chromatography, the isomers 5a/5b remain unseparable.
  • 46
    • 34250903274 scopus 로고    scopus 로고
    • Examples of intramolecular cyclic carbamate formation with good stereoselectivities have been reported in the iodocyclization of a few acyclic homoallyl-ß-amino esters (carbamates vs δ-lactones, ref 17) and in one case on the bromocyclization of a bicyclic allyl α-amino ester where, for steric reasons, only the C=O carbamate could give the nucleophilic attack ref 18
    • Examples of intramolecular cyclic carbamate formation with good stereoselectivities have been reported in the iodocyclization of a few acyclic homoallyl-ß-amino esters (carbamates vs δ-lactones) (ref 17) and in one case on the bromocyclization of a bicyclic allyl α-amino ester where, for steric reasons, only the C=O carbamate could give the nucleophilic attack (ref 18).
  • 50
    • 34250811118 scopus 로고    scopus 로고
    • Crystal Data for 7b: C14H16INO4, Mw, 389.18, T, 293(2) K, l, 0.71073 Å, orthorhombic, space group P212121, a, 6.725 Å, b, 13.858 Å, c, 16.061 Å, V, 1496.7 Å3, Z, 4, D c, 1.727 g/cm3, F(000, 768, crystal size 0.5 × 0.5 × 0.5 mm3, 24 277 reflections measured, 4577 independent reflections (Rint, 0.0206, the final wR(F2) was 0.1534 (all data) and final R was 0.0536 for 3704 unique data [I > 2s(I, The crystal structure of (4S,6R)-7b has been deposited at the Cambridge Crystallographic Data Centre CCDC 635632
    • 2) was 0.1534 (all data) and final R was 0.0536 for 3704 unique data [I > 2s(I)], The crystal structure of (4S,6R)-7b has been deposited at the Cambridge Crystallographic Data Centre (CCDC 635632).


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.