Generation of Phosphoranes Derived from Phosphites. A New Class of Phosphorus Ylides Leading to High E Selectivity with Semi-stabilizing Groups in Wittig Olefinations

Varinder K. Aggarwal,* J. Robin Fulton, Chris G. Sheldon, and Javier de Vicente
School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK
J. Am. Chem. Soc., 2003, 125 (20), pp 6034–6035
DOI: 10.1021/ja029573x
Publication Date (Web): April 29, 2003
Copyright © 2003 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.

, v.aggarwal@bristol.ac.uk

Abstract

Abstract Image

Tosylhydrazones derived from aryl aldehydes react with t-BuOK, ClFeTPP, (MeO)3P, and aldehydes to furnish olefins with high E selectivity. These reactions occur through a Wittig-type pathway via the corresponding diazo compounds, metal carbenes and phosphorous ylides, with the water-soluble trimethyl phosphate as the byproduct. Similar reactions can also be performed using ethyl diazoacetate; however, high E selectivity was only observed in the presence of LiBr. In this case, the reaction is believed to occur via the phosphonate anion, formed through an Arbuzov reaction. Thus this olefination reaction occurs through a Horner−Wadsworth−Emmons (HWE) reaction but the phosphonate anion is generated under completely base-free conditions.

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History

  • Published In Issue May 21, 2003
  • Received December 3, 2002

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