Related Experiment Video
Updated: May 31, 2026

Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization
Published on: November 29, 2018
Enantiospecific bromonium ion generation and intramolecular capture: a model system for asymmetric bromonium
D Christopher Braddock1, Jared S Marklew, Alexander J F Thomas
1Department of Chemistry, Imperial College London, London, SW7 2AZ, UK. c.braddock@imperial.ac.uk
Abstract:
Scalemic bromonium ions generated enantiospecifically by the action of catalytic triflic acid on scalemic regioisomeric bromohydrin derivatives are trapped intramolecularly, enantiospecifically and regioselectively to give bicyclic brominated carbocycles in excellent yield and high enantiomeric excess. This enantiospecific pathway is not significantly perturbed by the addition of a trisubstituted alkene.
More Related Videos
Related Concept Videos
Halogenation of Alkenes
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Formation of Halohydrin from Alkenes
Thermal and Photochemical Electrocyclic Reactions: Overview
Electrophilic Addition to Alkynes: Halogenation
Halogenation is another class of electrophilic addition reactions where a halogen molecule gets added across a π bond. In alkynes, the presence of two π bonds allows for the addition of two equivalents of halogens (bromine or chlorine). The addition of the first halogen molecule forms a trans-dihaloalkene as the major product and the cis isomer as the minor product. Subsequent addition of the second equivalent yields the tetrahalide.
Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene
Regioselectivity of Electrophilic Additions-Peroxide Effect

