title: Rearrangement of 3-membered 1,1,2-trifluorobromonium and iodonium ions and comparison of trifluorochloronium to fluorocarbenium ions.
abstract: Reactions of chlorine (Cl(2)) with 4-halo-1,1,2-trifluorobut-1-enes (1, 2, or 3) give open-ion intermediates A and E that are in equilibrium. The open-chloronium ions (E) rearrange to a five-membered-ring halonium ion during ionic chlorination of 3 when the number-4 halo-substituent is iodine. Three-membered-ring bromonium and iodonium ions from alkenes 1, 2, or 3 are rather symmetrical and similar in structure. Quantum chemical calculations show that five-membered-ring halonium ion intermediates are 11 to 27 kcal/mol more stable than the three-membered-ring halonium ions or the open-ions A and E. The five-membered-ring intermediates lead to rearranged products. Rearranged products increase as the number-4 halogen (Z) becomes more nucleophilic (Z: Cl < Br < I). Open chloronium ions from ionic chlorination of terminal fluorovinyl alkenes are compared to the open ions generated by protons to similar alkenes.
authors.affiliation: Department of Chemistry, Point Loma Nazarene University, San Diego, CA 92106-2899, USA. dshellha@pointloma.edu
authors.forename: Dale F
authors.initials: DF
authors.lastname: Shellhamer
authors.forename: Kevyn J
authors.initials: KJ
authors.lastname: Davenport
authors.forename: Heidi K
authors.initials: HK
authors.lastname: Forberg
authors.forename: Matthew P
authors.initials: MP
authors.lastname: Herrick
authors.forename: Rachel N
authors.initials: RN
authors.lastname: Jones
authors.forename: Sean J
authors.initials: SJ
authors.lastname: Rodriguez
authors.forename: Sunamita
authors.initials: S
authors.lastname: Sanabria
authors.forename: Nicole N
authors.initials: NN
authors.lastname: Trager
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Weiss
authors.forename: Victor L
authors.initials: VL
authors.lastname: Heasley
authors.forename: Jerry A
authors.initials: JA
authors.lastname: Boatz