1,2-Chlorine atom migration in 3-chloro-2-butyl radicals: a computational studyElectronic supplementary information (ESI) available: Calculated energies and enthalpies of stationary points, full structural information, and structures of trans-but-2-ene (9) and trans-but-2-ene radical (10). See http://www.rsc.org/suppdata/ob/b2/b209981k/
Neumann, Bernd; Zipse, Hendrik; Neumann Bernd; Department Chemie, Ludwig-Maximilians-Universität München; Zipse Hendrik; Department Chemie, Ludwig-Maximilians-Universität München
Журнал:
Organic & Biomolecular Chemistry
Дата:
2002
Аннотация:
Skellâ s hypothesis of bridged 2-haloalkyl radicals has been revisited using several different theoretical methods and the 3-chloro-2-butyl radical as an example.; 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 β-chloroalkyl radical. Reaction barriers for the 1,2-chlorine migration process are higher than those for rotation around the central Câ 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 β-(dialkoxyphosphoryloxy)alkyl radicals and suggests that chlorine migration can be influenced by polar substituent effects.
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