Generation of Halomethyl Radicals by Halogen Atom Abstraction and Their Addition Reactions with Alkenes.

α-Aminoradicals undergo halogen atom abstraction to form halomethyl radicals in reactions initiated by the combination of tert-butyl hydroperoxide, aliphatic trialkylamine, halocarbon, and copper(I) iodide. The formation of the α-aminoradical circumvents preferential hydrogen atom transfer in favor of halogen atom transfer, thereby releasing the halomethyl radical for addition to alkenes. The resulting radical addition products add the tert-butylperoxy group to form α-peroxy-β,β-dichloropropylbenzene products that are convertible to their corresponding β,β-dichloro-alcohols and to novel pyridine derivatives. Computational analysis clearly explains the deviation from traditional HAT of chloroform and also establishes formal oxidative addition/reductive elimination as the lowest energy pathway.