title: Carboniumvs.carbenium ion-like transition state geometries for carbocation cyclization - how strain associated with bridging affects 5-exo vs.6-endoselectivity.
abstract: Quantum chemical calculations are used to explore the origins of regioselectivity for proton-, Pt(II)- and Pd(II)-promoted cyclizations of 1,5-hexadienes, 5-aminoalkenes, and allylic acetimidates. The strain associated with achieving carbonium ion-like transition state geometries is shown to be a key factor in controlling 5-exo vs.6-endoselectivity.
authors.affiliation: Department of Chemistry, University of California-Davis, 1 Shields Avenue, Davis, CA 95616, USA.
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Gutierrez
authors.affiliation: Department of Chemistry, University of California-Davis, 1 Shields Avenue, Davis, CA 95616, USA.
authors.forename: Jason G
authors.initials: JG
authors.lastname: Harrison
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, North Carolina 27599-3190, USA.
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Felix
authors.affiliation: Instituto de Química, Universidad Nacional Autónoma de México, México D.F. 04510, Mexico.
authors.forename: Fernando Cortés
authors.initials: FC
authors.lastname: Guzman
authors.affiliation: Department of Chemistry, University of North Carolina at Chapel Hill, North Carolina 27599-3190, USA.
authors.forename: Michel R
authors.initials: MR
authors.lastname: Gagné
authors.affiliation: Department of Chemistry, University of California-Davis, 1 Shields Avenue, Davis, CA 95616, USA.
authors.forename: Dean J
authors.initials: DJ
authors.lastname: Tantillo