Alkene + HBR + ROOR - Reaction Mechanism

TL;DR

When an alkene is mixed with HBr in the presence of peroxides, the bromine atom will attach to a primary carbon instead of a secondary carbon.

Transcript

in this video we're going to talk about what happens when we mix an alkene with hbr in the presence of peroxides but first let's see what happens when we mix hbr in the absence of an organic peroxide now there's two carbon atoms that we need to pay attention to it's the two carbon atoms that are part of the double bond one is primary the other is s... Read More

Key Insights

• ❓ Alkene reactions with HBr can result in different products depending on the presence or absence of peroxides.
• 🪜 Without peroxides, HBr adds to the alkene's double bond, resulting in the attachment of bromine to the more substituted carbon.
• 🥺 Peroxides activate the reaction and facilitate anti-Markovnikov carbocation chemistry, leading to bromine attachment on a primary carbon.
• ❓ The stability of carbocations determines the regioselectivity of the reaction.
• ⛓️ The presence of peroxides initiates a chain reaction involving oxygen radicals and hydrobromic acid.
• 🖐️ Carbocation stability plays a crucial role in determining the reaction products.
• 💁 The reaction mechanism involves nucleophilic behavior of the alkene, carbocation formation, and bromide ion attacking the carbocation.

Summary & Key Takeaways

• Mixing HBr with an alkene in the absence of peroxides results in an electrophilic addition reaction, where HBr adds across the double bond.

• In the presence of peroxides, the reaction proceeds with anti-Markovnikov carbocation chemistry, leading to the bromine atom attaching to a primary carbon.

• The mechanism involves the alkene behaving as a nucleophile, carbocation formation, and bromide ion attacking the carbocation.