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Volumn 61, Issue 26, 2005, Pages 6447-6459

Stereoselective synthesis of N-protected pyrrolidines via Pd-catalyzed reactions of γ-(N-acylamino) alkenes and γ-(N-Boc-amino) alkenes with aryl bromides

Author keywords

Arylhalide; Diastereoselectivity; Palladium; Pyrrolidines; Stereoselective synthesis

Indexed keywords

ALKENE DERIVATIVE; BROMINE DERIVATIVE; PALLADIUM; POLYCYCLIC AROMATIC HYDROCARBON DERIVATIVE; PYRROLIDINE DERIVATIVE; VINYL DERIVATIVE;

EID: 20444461630     PISSN: 00404020     EISSN: None     Source Type: Journal    
DOI: 10.1016/j.tet.2005.03.110     Document Type: Article
Times cited : (75)

References (58)
  • 5
    • 0000826734 scopus 로고    scopus 로고
    • For examples of pyrrolidine synthesis that involve intramolecular C-N bond formation and intermolecular C-C bond formation, see: (a) Y. Tamaru, and M. Kimura Synlett 1997 749 757
    • (1997) Synlett , pp. 749-757
    • Tamaru, Y.1    Kimura, M.2
  • 10
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    • For related transformations that afford indoline or tetrahydrofuran products, see: (a) R. Lira, and J.P. Wolfe J. Am. Chem. Soc. 126 2004 13906 13907
    • (2004) J. Am. Chem. Soc. , vol.126 , pp. 13906-13907
    • Lira, R.1    Wolfe, J.P.2
  • 12
    • 0001080997 scopus 로고    scopus 로고
    • Several examples of cleavage of p-methoxyphenyl groups from nitrogen have been described. However, these transformations are typically facilitated by the use of strong oxidants and exhibit relatively low functional group tolerance. See: (a) S. Saito, K. Hatanaka, and H. Yamamoto Org. Lett. 2 2000 1891 1894
    • (2000) Org. Lett. , vol.2 , pp. 1891-1894
    • Saito, S.1    Hatanaka, K.2    Yamamoto, H.3
  • 16
    • 20444467459 scopus 로고    scopus 로고
    • note
    • Dpe-phos=bis(2-diphenylphosphinophenyl) ether. Dppf=1,1′- bis(diphenylphosphinoferrocene). Xantphos=9,9-dimethyl-4,5- bis(diphenylphosphino) xanthene. Dppe=1,2-bis(diphenylphosphino) ethane. Dppb=1,4-bis(diphenylphosphino) butane. Nixantphos=4,6-bis(diphenylphosphino) phenoxazine.
  • 19
    • 0042291889 scopus 로고    scopus 로고
    • D. Astruc Wiley-VCH Weinhem, Germany
    • J.F. Hartwig D. Astruc Modern Arene Chemistry 2002 Wiley-VCH Weinhem, Germany 107 168
    • (2002) Modern Arene Chemistry , pp. 107-168
    • Hartwig, J.F.1
  • 20
    • 0025029284 scopus 로고
    • Balme has previously described the Pd/dppp-catalyzed Heck arylation of 4a with iodobenzene. See: G. Fournet, G. Balme, and J. Gore Tetrahedron 46 1990 7763 7774
    • (1990) Tetrahedron , vol.46 , pp. 7763-7774
    • Fournet, G.1    Balme, G.2    Gore, J.3
  • 22
    • 20444495080 scopus 로고    scopus 로고
    • note
    • Control experiments demonstrated the Boc-cleavage is base-induced (not Pd-catalyzed). See Ref. 12.
  • 23
    • 20444490138 scopus 로고    scopus 로고
    • note
    • The product isolated from this reaction contained ca 15% of the corresponding dihydropyrrole. Similar side reactions have been previously observed in reactions of 2-allylaniline or γ-N-arylaminoalkenes with electron-rich aryl bromides. See Refs. 4,5a.
  • 26
    • 20444473940 scopus 로고    scopus 로고
    • note
    • The base induced substrate olefin isomerization was only observed in reactions of 2-allylaniline derivatives.
  • 29
    • 20444443337 scopus 로고    scopus 로고
    • note
    • Proton NMR analysis of crude reaction mixtures revealed diastereomer ratios of 10-20:1; the minor diastereomer was usually readily separated by chromatography to provide isolated products with >20:1 dr. Thus, diastereomeric ratios reported in Table 4 represent ratios of diastereomers for the isolated material upon which the yield is based. The diastereomeric ratios observed in crude reaction mixtures were >20:1 for 2,5-disubstituted pyrrolidines, >20:1 for 6-substituted hexahydrocyclopenta[b]pyrroles, and ca 10:1 for 2,3-disubstituted pyrrolidines.
  • 30
    • 20444477708 scopus 로고    scopus 로고
    • note
    • 1H NMR analysis.
  • 31
    • 20444433347 scopus 로고    scopus 로고
    • note
    • The Pd/dpe-phos-catalyzed reaction of a N-Boc protected substrate bearing an internal acyclic alkene afforded a single pyrrolidine product, albeit in low yield (ca 20%).
  • 37
    • 20444442934 scopus 로고    scopus 로고
    • note
    • Although we currently favor this mechanistic hypothesis, an alternate mechanism involving alkene insertion into the Pd-C bond of 33 followed by C-N bond-forming reductive elimination cannot be excluded in all transformations.
  • 42
    • 0038276962 scopus 로고    scopus 로고
    • Electron-donating groups may facilitate β-hydride elimination by stabilizing the developing positive charge on the β-carbon in the transition state. See: J.A. Mueller, and M.S. Sigman J. Am. Chem. Soc. 125 2003 7005 7013
    • (2003) J. Am. Chem. Soc. , vol.125 , pp. 7005-7013
    • Mueller, J.A.1    Sigman, M.S.2
  • 43
    • 20444457375 scopus 로고    scopus 로고
    • note
    • The small size of the N-acyl and N-Boc substituents relative to N-aryl groups may also alter the rate of β-hydride elimination in some systems.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.