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Volumn 12, Issue 15, 2010, Pages 3328-3331

A modular sydnone cycloaddition/Suzuki-Miyaura cross-coupling strategy to unsymmetrical 3,5-bis(hetero)aromatic pyrazoles

Author keywords

[No Author keywords available]

Indexed keywords

ALKYNE; BORONIC ACID DERIVATIVE; HALOGENATED HYDROCARBON; PALLADIUM; PYRAZOLE DERIVATIVE; SYDNONE DERIVATIVE;

EID: 77955156824     PISSN: 15237060     EISSN: 15237052     Source Type: Journal    
DOI: 10.1021/ol101087j     Document Type: Article
Times cited : (67)

References (58)
  • 9
    • 13644268558 scopus 로고    scopus 로고
    • For reviews on site-selective cross-coupling reactions of polyhalogenated heteroarene derivatives, see: Schröter, S.; Stock, C.; Bach, T. Tetrahedron 2005, 61, 2245
    • (2005) Tetrahedron , vol.61 , pp. 2245
    • Schröter, S.1    Stock, C.2    Bach, T.3
  • 20
    • 77955153694 scopus 로고    scopus 로고
    • Recently, bisarylic pyrazoles have also been obtained via direct C-H bond arylations
    • Recently, bisarylic pyrazoles have also been obtained via direct C-H bond arylations
  • 27
    • 58149305979 scopus 로고    scopus 로고
    • The capability of 4-halosydnones to undergo palladium-catalyzed cross-coupling reactions has drawn recent attention on these mesionic compounds; see: Browne, D. L.; Taylor, J. B.; Plant, A.; Harrity, J. P. A. J. Org. Chem. 2009, 74, 396
    • (2009) J. Org. Chem. , vol.74 , pp. 396
    • Browne, D.L.1    Taylor, J.B.2    Plant, A.3    Harrity, J.P.A.4
  • 29
    • 77955125849 scopus 로고    scopus 로고
    • Recently, Harrity reported the synthesis of pyrazoleboronic esters via sydnone cycloaddition with alkynylboranes and their subsequent use in cross-coupling reactions allowing functionalization at the pyrazole C-4 position
    • Recently, Harrity reported the synthesis of pyrazoleboronic esters via sydnone cycloaddition with alkynylboranes and their subsequent use in cross-coupling reactions allowing functionalization at the pyrazole C-4 position
  • 37
    • 34249819690 scopus 로고    scopus 로고
    • For other heterocycloadditions of alkynyl halides, see: Lu, J.-Y.; Arndt, H.-D. J. Org. Chem. 2007, 72, 4205
    • (2007) J. Org. Chem. , vol.72 , pp. 4205
    • Lu, J.-Y.1    Arndt, H.-D.2
  • 39
    • 77955162060 scopus 로고    scopus 로고
    • Previous reports dealing with 3-phenylsydnone cycloaddition involving unsymmetrical alkynyl esters have essentially concerned the case of unsubstituted propiolates. It was established that regioisomeric mixtures where the cycloadduct having the ester group in the 3-position predominated were normally formed in these reactions. The observed selectivities have been explained in terms of HOMO-LUMO interactions, the dipole LUMO and dipolarophile HOMO interaction being suggested to be the controlling term
    • Previous reports dealing with 3-phenylsydnone cycloaddition involving unsymmetrical alkynyl esters have essentially concerned the case of unsubstituted propiolates. It was established that regioisomeric mixtures where the cycloadduct having the ester group in the 3-position predominated were normally formed in these reactions. The observed selectivities have been explained in terms of HOMO-LUMO interactions, the dipole LUMO and dipolarophile HOMO interaction being suggested to be the controlling term
  • 45
    • 77955135098 scopus 로고    scopus 로고
    • Quantum chemistry calculation using DFT suggested a favorable interaction between the dipole HOMO and the dipolarophile LUMO for the cycloaddition of 4-halosydnones (1) with ethyl halopropiolates (2). However, simple consideration of orbital lobe sizes did not allow a quantitative prediction of regioselectivity. See Supporting Information for details
    • Quantum chemistry calculation using DFT suggested a favorable interaction between the dipole HOMO and the dipolarophile LUMO for the cycloaddition of 4-halosydnones (1) with ethyl halopropiolates (2). However, simple consideration of orbital lobe sizes did not allow a quantitative prediction of regioselectivity. See Supporting Information for details.
  • 46
    • 77955170275 scopus 로고    scopus 로고
    • In accordance with literature precedents (ref 10a), bromosydnone 1b was found to be fairly unstable under the reaction conditions (elevated temperature and non-polar solvent), although some 3-aryl-4-bromosydnones have been previously successfully reacted with dimethyl acetylenedicarboxylate under similar conditions (refs 10b, 10c)
    • In accordance with literature precedents (ref 10a), bromosydnone 1b was found to be fairly unstable under the reaction conditions (elevated temperature and non-polar solvent), although some 3-aryl-4-bromosydnones have been previously successfully reacted with dimethyl acetylenedicarboxylate under similar conditions (refs 10b, 10c).


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.