Absolute rate constants for hydrocarbon autoxidation. 26. Rate constants for reaction of the tert-butylperoxy radical with 1-bromo-2-methylbutane and 1-bromo-3-methylbutane and some related substituted butanes

Rate constants and Arrhenius parameters for reaction of the tert-butylperoxy radical with 1-bromo-2-methylbutane and 1-bromo-3-methylbutane in solution from 30–80 °C have been estimated. The magnitude of these kinetic parameters are consistent with activation of the tertiary hydrogen vicinal to the bromine substituent and the involvement of a "bridged" transition state in the hydrogen atom transfer reaction.Chloro, trimethylsilyl, and trimethylstannyl substituents also activate a vicinal tertiary hydrogen and activation increases in the order trimethylsilyl ∼ trimethylstannyl < chloro < bromo.