Spontaneous formation of PMB esters using 4-methoxybenzyl-2,2,2- trichloroacetimidate

Jigisha P. Shah, Christopher M. Russo, Kyle T. Howard, John D. Chisholm

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

Carboxylic acids are converted to the corresponding 4-methoxybenzyl (PMB) esters with 4-methoxybenzyl-2,2,2-trichloroacetimidate in the absence of an acid catalyst. This operationally simple procedure is a highly effective method for the formation of PMB esters. The reaction is promoted by the carboxylic acids themselves in excellent yields (72-99%). Sterically hindered carboxylic acids, which provide lower yields with other imidates, are esterified in higher yield with the more reactive PMB imidate. No racemization is observed in the case of carboxylic acids bearing an α-stereocenter, and no isomerization is observed with Z-α,β-unsaturated acids. This method may therefore find use in the esterification of complex or sensitive substrates where more common techniques lead to decomposition.

Original languageEnglish (US)
Pages (from-to)1740-1742
Number of pages3
JournalTetrahedron Letters
Volume55
Issue number10
DOIs
StatePublished - Mar 5 2014

Keywords

  • Carboxylic acid
  • Esterification
  • PMB ester
  • Protecting groups
  • Trichloroacetimidate

ASJC Scopus subject areas

  • Biochemistry
  • Drug Discovery
  • Organic Chemistry

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