Gas-phase fragmentation of deprotonated p-hydroxyphenacyl derivatives

J Org Chem. 2011 Apr 1;76(7):2180-6. doi: 10.1021/jo1025223. Epub 2011 Mar 8.

Abstract

Electrospray ionization of methanolic solutions of p-hydroxyphenacyl derivatives HO-C(6)H(4)-C(O)-CH(2)-X (X = leaving group) provides abundant signals for the deprotonated species which are assigned to the corresponding phenolate anions (-)O-C(6)H(4)-C(O)-CH(2)-X. Upon collisional activation in the gas phase, these anions inter alia undergo loss of a neutral "C(8)H(6)O(2)" species concomitant with formation of the corresponding anions X(-). The energies required for the loss of the neutral roughly correlate with the gas phase acidities of the conjugate acids (HX). Extensive theoretical studies performed for X = CF(3)COO in order to reveal the energetically most favorable pathway for the formation of neutral "C(8)H(6)O(2)" suggest three different routes of similar energy demands, involving a spirocyclopropanone, epoxide formation, and a diradical, respectively.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetophenones / chemistry*
  • Anions / chemistry*
  • Cyclopropanes / chemistry*
  • Epoxy Compounds / chemistry*
  • Models, Theoretical
  • Molecular Structure
  • Noble Gases / chemistry*
  • Solutions / chemistry
  • Spectrometry, Mass, Electrospray Ionization
  • Spiro Compounds / chemistry*

Substances

  • Acetophenones
  • Anions
  • Cyclopropanes
  • Epoxy Compounds
  • Noble Gases
  • Solutions
  • Spiro Compounds