Related Experiment Video
Updated: Feb 27, 2026

Protocol for the Synthesis of Ortho-trifluoromethoxylated Aniline Derivatives
Published on: January 19, 2016
Combining Eosin Y with Selectfluor: A Regioselective Brominating System for Para-Bromination of Aniline Derivatives
Binbin Huang1, Yating Zhao1, Chao Yang1
1State Key Lab of Urban Water Resource and Environment, School of Chemistry and Chemical Engineering, Harbin Institute of Technology (Shenzhen) , Shenzhen 518055, China.
Abstract:
A mild, metal-free, and absolutely para-selective bromination of aniline derivatives has been developed in excellent yields, wherein the organic dye Eosin Y is employed as the bromine source in company with Selectfluor. Neither air nor moisture sensitive, this facile reaction proceeds smoothly at room temperature and completes within a short time. Mechanistic studies indicate a radical pathway; therefore, the existence of an in situ generated brominating reagent, "Selectbrom", is postulated, which may reasonably account for the unique regioselectivity for the para-bromination of N-acyl- as well as N-sulfonylanilines.
More Related Videos
Related Concept Videos
Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
α-Bromination of Carboxylic Acids: Hell–Volhard–Zelinski Reaction
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.
Radical Substitution: Allylic Bromination
Electrophilic Aromatic Substitution: Chlorination and Bromination of Benzene
Regioselectivity of Electrophilic Additions-Peroxide Effect

