title: 1,2-Chlorine atom migration in 3-chloro-2-butyl radicals: a computational study.
abstract: The structure as well as several unimolecular reaction pathways of the 3-chloro-2-butyl radical 1 have been studied at several different theoretical levels (B3LYP/aug-cc-pVDZ, BHLYP/aug-cc-pVDZ, G3(ROMP2)B3). The symmetrically chlorine-bridged structure is a transition state at all levels of theory and the most favorable ground state structure is the unbridged beta-chloroalkyl radical. Reaction barriers for the 1,2-chlorine migration process are higher than those for rotation around the central C-C bond. 1,2-migration of the chlorine atom is accompanied by an increase in chlorine negative charge as well as chlorine spin density. This hybrid homo-/heterolytic process is well known from rearrangement reactions in beta-(dialkoxyphosphoryloxy)alkyl radicals and suggests that chlorine migration can be influenced by polar substituent effects.
authors.affiliation: Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 13, D-82131 München, Germany.
authors.forename: Bernd
authors.initials: B
authors.lastname: Neumann
authors.forename: Hendrik
authors.initials: H
authors.lastname: Zipse