brominating

Brominating refers to the chemical process of introducing bromine into a substrate. The term covers several reaction types, including electrophilic bromination of alkenes and arenes, as well as radical bromination of carbon-hydrogen bonds.

Electrophilic bromination of alkenes proceeds through a bromonium ion intermediate, adding bromine across the double bond to give vicinal dibromides. In arenes, bromination proceeds by electrophilic aromatic substitution, typically with Br2 and a Lewis acid catalyst (such as FeBr3), favoring ortho or para substitution relative to activating groups.

Radical bromination targets relatively weak C–H bonds, such as allylic or benzylic positions, using radical initiators or N-bromosuccinimide (NBS) under light or heat. Selectivity reflects bond-dissociation energies and resonance stabilization of the resulting radical.

Brominated products serve as versatile intermediates in pharmaceutical and materials chemistry, enabling further transformations via cross-coupling, or as building blocks in natural product synthesis.

Bromine and many brominating reagents are corrosive and toxic; reactions should be conducted in a fume hood with appropriate PPE. Waste management and handling of brominated byproducts require caution.