Rate Constants for Halogen Atom Transfer from Representative α-Halocarbonyl Compounds to Primary Alkyl Radicals

Article abstract of DOI:10.1021/jo00269a016

Rate constants for halogen atom transfer from diethyl methyliodomalonate (7a), iodoacetonitrile (7b), ethyl 2-methyl-2-iodopropanoate (7c), ethyl iodoacetate (7d), diethyl methylbromomalonate (7e), and ethyl bromoacetate (7f) to simple primary alkyl radicals have been studied by a variety of competition reactions.The Arrhenius functions for halogen atom transfer to the undecyl radical from halides 7d and 7f are log (k_I, M^-1 s^-1) = 10.4 - 4.4/θ and log (k_Br, M^-1 s^-1) = 10.4 - 8.2/θ, respectively.The rate constants for halogen atom transfer to a primaryradical from the series of compounds 7a-7f at 50 deg C are 1.8 x 10⁹, 1.7 x 10⁹, ca. 6 x 10⁸, 2.6 x 10⁷, 1.0 x 10⁶, and 7.0 x 10⁴ M^-1 s^-1, respectively.The kinetic values are useful for the planning of synthetic methods that incorporate an atom transfer-cyclization process.