Allylic/Benzylic Bromination With N-Bromo Succinimide (NBS)

The video explains radical halogenation, focusing on bromination at allylic and benzylic positions. It introduces N-Bromosuccinimide (NBS) as a preferred reagent over molecular bromine to avoid unwanted addition reactions. The mechanism involves bromine radicals interacting with allylic substrates, leading to successful bromination. Key to the process is maintaining low concentrations of species that react with pi bonds, allowing radical chemistry to proceed.

What is the primary focus of radical halogenation discussed in the video?

• Chlorination of alkanes

• Iodination of alkanes

• Fluorination of alkanes

• Bromination of alkanes

What is the allylic position in a molecule?

• Carbon adjacent to a triple bond

• Carbon adjacent to a double bond

• Carbon adjacent to a benzene ring

• Carbon adjacent to a single bond

Why is N-Bromosuccinimide (NBS) preferred over molecular bromine for certain reactions?

• NBS is less toxic than molecular bromine

• NBS is more reactive than molecular bromine

• NBS prevents dibromination with pi bonds

• NBS is cheaper than molecular bromine

What role does hydrobromic acid play in the bromination mechanism with NBS?

• It acts as a solvent

• It catalyzes the formation of bromine radicals

• It prevents the reaction from occurring

• It stabilizes the allylic radical

How is the allylic radical stabilized during the bromination process?

• By ionic interaction

• By forming a covalent bond

• By resonance with a pi bond

• By hydrogen bonding