Nitroxide chemistry. Part VIII. Abstraction of allylic hydrogen from isobutene by bistrifluoromethyl nitroxide

Abstract

Vapour-phase reaction of isobutene with bistrifluoromethyl nitroxide at 200 °C and low pressure leads to the formation of the 1 : 2 olefin–nitroxide adduct Me₂R·CH₂R and, mainly, the product arising from free-radical abstraction of allylic hydrogen, RCH₂·CMe:CH₂[R =(CF₃)₂N·O]. The former product is best prepared on a large scale by passing the nitroxide into the liquid olefin at ca.–60 °C. Acid-catalysed reaction of NN-bistrifluoromethylhydroxylamine with isobutene constitutes a convenient laboratory route to the amino-oxypropane Me₃CR.