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Volumn 121, Issue 44, 1999, Pages 10251-10263

A palladium-catalyzed method for the preparation of indoles via the Fischer indole synthesis

Author keywords

[No Author keywords available]

Indexed keywords

INDOLE DERIVATIVE; PALLADIUM;

EID: 0033544422     PISSN: 00027863     EISSN: None     Source Type: Journal    
DOI: 10.1021/ja992077x     Document Type: Article
Times cited : (259)

References (54)
  • 22
    • 13044252182 scopus 로고    scopus 로고
    • reported by: Buchwald, S. L. Abstracts of Papers, Boston, MA, Fall 1998; American Chemical Society: Washington, DC
    • Work of Old, D. W., reported by: Buchwald, S. L. Abstracts of Papers, 216th National Meeting of the American Chemical Society, Boston, MA, Fall 1998; American Chemical Society: Washington, DC, 1998; U351.
    • (1998) 216th National Meeting of the American Chemical Society
    • Old, D.W.1
  • 30
    • 13044313271 scopus 로고    scopus 로고
    • note
    • Azine byproducts were formed during the coupling reaction of nonbenzophenone-derived simple hydrazones, as determined by GC/MS. For discussions on the stability of simple hydrazones, see refs 31-33.
  • 32
    • 0013461862 scopus 로고
    • Breslow, R. Ed.; John Wiley and Sons: New York
    • Day, A. C.; Whiting, M. C. In Organic Syntheses; Breslow, R. Ed.; John Wiley and Sons: New York, 1970; Vol. 50, pp 3-6.
    • (1970) Organic Syntheses , vol.50 , pp. 3-6
    • Day, A.C.1    Whiting, M.C.2
  • 35
    • 0032560932 scopus 로고    scopus 로고
    • We have also been able to couple benzophenone hydrazone with aryl chlorides employing a Pd/2-dicyclohexylphosphino-2′-dimethylaminobiphenyl-based catalyst system. By this method, hydrazone 4f was produced in 89% yield from benzophenone hydrazone and 4-chlorotoluene employing 1 mol % of this catalyst mixture. For a discussion on the use of this ligand for Pd-catalyzed cross-coupling reactions of aryl chlorides, see: Old, D. W.; Wolfe, J. P.; Buchwald, S. L. J. Am. Chem. Soc. 1998, 120, 9722.
    • (1998) J. Am. Chem. Soc. , vol.120 , pp. 9722
    • Old, D.W.1    Wolfe, J.P.2    Buchwald, S.L.3
  • 39
    • 13044316348 scopus 로고    scopus 로고
    • note
    • The reaction of 4-bromoveratrole with benzophenone hydrazone requires 12 h to go to completion. In contrast, the coupling reactions to prepare hydrazones 4a-d are complete in 1.5-6 h.
  • 40
    • 84987274103 scopus 로고
    • Adams, R. Ed.; John Wiley & Sons: New York
    • Todd, D. In Organic Reactions; Adams, R. Ed.; John Wiley & Sons: New York, 1948; Vol. IV, p 391.
    • (1948) Organic Reactions , vol.4 , pp. 391
    • Todd, D.1
  • 41
    • 13044290438 scopus 로고    scopus 로고
    • note
    • Control experiments showed that, under typical reaction conditions in the absence of Pd, after 16 h approximately 40% of the benzophenone hydrazone undergoes base-promoted Wolff-Kishner reduction to form diphenylmethane. The formation of an N-aryl benzophenone hydrazone is not observed without the use of a Pd catalyst.
  • 44
    • 13044270782 scopus 로고    scopus 로고
    • note
    • The use of aldehydes in this procedure does initially produce 2-H indole products. However, due to the low reaction pH, the 2-H indole products undergo oligomerization, resulting in low to moderate isolated yields of the desired indole product (see ref 45). We are currently investigating alternative approaches for the preparation of 2-H indoles from aldehydes and hydrazones 4.
  • 47
    • 13044316349 scopus 로고    scopus 로고
    • note
    • p-Methoxy-substituted arylhydrazines are particularly prone to N-N bond cleavage. See ref 3.
  • 48
    • 13044284528 scopus 로고    scopus 로고
    • note
    • In comparison, the bite angle of BINAP is 92°. See ref 49.


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.