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

Abstract

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 (kI, M-1s-1) = 10.4 - 4.4/0 and log (KBr, M-1s-1) = 10.4 - 8.2/0, respectively. The rate constants for halogen atom transfer to a primary radical from the series of compounds 7a-f at 50 °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-1s-1, respectively. The kinetic values are useful for the planning of synthetic methods that incorporate an atom transfer-cyclization process.

Document Type

Article

DOI

https://doi.org/10.1021/jo00269a016

Publication Date

4-1-1989

Journal Title

Journal of Organic Chemistry

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