An electron spin resonance study of 3-oxypropenoyl radicals derived from glycidols

Abstract

Glycidols with blocked OH groups (A; M = alkyl or trialkylsilyl) react with t-butoxyl radicals to show the e.s.r. spectra of the corresponding 3-oxypropenoyl radicals (D), and 24 examples of these acyl radicals are reported. The [graphic ommitted] reaction is thought to proceed through the formation of the allyloxyl radicals (B), which, in part, are converted into the aldehyde (C) which is very reactive towards loss of hydrogen to give the acyl radical (D). Glycidyl pivalate (A; M = COCMe₃) reacts cleanly in this way, but glycidyl acetate (E; R = Me) also undergoes intramolecular 1,5-transfer of the acyl group to show the spectrum of the enoxyl radical (F). Glycidyl propionate and butyrate do not undergo this acyl transfer, but show the spectra of the radicals OĊCHCHOCOCH₂R′ and [graphic omitted]HCH₂OCOĊHR′(R′= Me or Et). [graphic ommitted]