Palladium-Catalyzed Synthesis of Aryl Ketones by Coupling of Aryl Bromides with an Acyl Anion Equivalent

Akihiro Takemiya and John F. Hartwig*
Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520-8107
J. Am. Chem. Soc., 2006, 128 (46), pp 14800–14801
DOI: 10.1021/ja064782t
Publication Date (Web): November 2, 2006
Copyright © 2006 American Chemical Society
*

In papers with more than one author, the asterisk indicates the name of the author to whom inquiries about the paper should be addressed.

, john.hartwig@yale.edu

Abstract

Abstract Image

Palladium-catalyzed couplings of aryl bromides with N-tert-butylhydrazones as acyl anion equivalents to form aryl ketones are reported. The coupling process occurs at the C-position of hydrazones to form N-tert-butyl azo compounds. Isomerization of these azo compounds to the corresponding hydrazones, followed by hydrolysis, gave the desired mixed alkyl aryl ketones. The selectivity of C- versus N-arylation was strongly influenced by the substituent on nitrogen. Arylation at carbon occurred with N-tert-butylhydrazones, whereas N-arylation occurred with N-arylhydrazones. The arylation of hydrazones containing primary and secondary alkyl groups, as well as aryl groups, gave the desired ketones in good yields after hydrolysis. Functional groups on the aromatic ring, such as alkoxy, cyano, trifluoromethyl, carboalkoxy, carbamoyl, and keto groups, were tolerated. This reaction likely occurs by C−C bond-forming reductive elimination from an intermediate containing an η1-diazaallyl ligand.

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History

  • Published In Issue November 22, 2006
  • Received July 5, 2006

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