Efficient Synthesis of α-Aryl Esters by Room-Temperature Palladium-Catalyzed Coupling of Aryl Halides with Ester Enolates

Morten Jørgensen, Sunwoo Lee, Xiaoxiang Liu, Joanna P. Wolkowski, and John F. Hartwig*
Contribution from the Department of Chemistry, Yale University, P.O. Box 208107, New Haven, Connecticut 06520-8107
J. Am. Chem. Soc., 2002, 124 (42), pp 12557–12565
DOI: 10.1021/ja027643u
Publication Date (Web): September 28, 2002
Copyright © 2002 American Chemical Society
*

 To whom correspondence should be addressed. E-mail:  john.hartwig@yale.edu.

Abstract

Abstract Image

A catalytic amount of Pd(dba)2 ligated by either carbene precursor N,N‘-bis(2,6-diisopropylphenyl)-4,5-dihydroimidazolium (1) or P(t-Bu)3 mediated the coupling of aryl halides and ester enolates to produce α-aryl esters in high yields at room temperature. The reaction was highly tolerant of functionalities and substitution patterns on the aryl halide. Improved protocols for the selective monoarylation of tert-butyl acetate and the efficient arylation of α,α-disubstituted esters were developed with LiNCy2 as base and P(t-Bu)3 as ligand. In addition, tert-butyl esters, such as those of Naproxen and Flurbiprofen, were prepared from tert-butyl propionate and aryl bromides in high yields in the presence of Pd(dba)2 and the hindered, saturated heterocyclic carbene ligand precursor.

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History

  • Published In Issue October 23, 2002
  • Received July 10, 2002

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