ACYL NITROXIDES .2. REACTIONS WITH HYDROCARBONS

The reactions of benzoyl t-butyl nitroxide with a range of hydrocarbon substrates are described. Hydrogen abstraction (leading to substitution) is observed with alkenes having reactive allylic hydrogens, and with aralkanes. Other alkenes give addition products. With alkanes a radical self-reaction competes with hydrogen abstraction, although good yields of substitution product may sometimes be obtained using the more reactive 3,5-dinitrobenzoyl t-butyl nitroxide. Kinetic data are reported for reaction of the benzoyl nitroxide with cumene [equation (3)], and relative reactivity data are recorded for other alkylbenzenes; using a series of substituted toluenes, correlation with σ+ gives a ρ-value of -0.9 (at 90 °C). Reaction of the benzoyl nitroxide with a series of aldehydes gives O-acyl-N-benzoyl-N-t- butylhydroxylamines.