Pd-Catalyzed Intermolecular Amidation of Aryl Halides:  The Discovery that Xantphos Can Be Trans-Chelating in a Palladium Complex

Jingjun Yin and Stephen L. Buchwald*
Contribution from the Department of Chemistry, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
J. Am. Chem. Soc., 2002, 124 (21), pp 6043–6048
DOI: 10.1021/ja012610k
Publication Date (Web): May 4, 2002
Copyright © 2002 American Chemical Society
*

 Corresponding author. E-mail:  sbuchwal@mit.edu.

Abstract

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A general method for the intermolecular coupling of aryl halides and amides using a Xantphos/Pd catalyst is described. This system displays good functional group compatibility, and the desired C−N bond forming process proceeds in good to excellent yields with 1−4 mol % of the Pd catalyst. Additionally, the arylation of sulfonamides, oxazolidinones, and ureas is reported. The efficiency of these transformations was found to be highly dependent on reaction concentrations and catalyst loadings. A Pd complex resulting from oxidative addition of 4-bromobenzonitrile, (Xantphos)Pd(4-cyanophenyl)(Br) (II), was prepared in one step from Xantphos, Pd2(dba)3, and the aryl bromide. Complex II proved to be an active catalyst for the coupling between 4-bromobenzonitrile and benzamide. X-ray crystallographic analysis of II revealed a rare trans-chelating bisphosphine-Pd(II) structure with a large bite angle of 150.7°.

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History

  • Published In Issue May 29, 2002
  • Received November 29, 2001

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