What Happens When an Alkene Reacts with Br2 and Water?

TL;DR

The reaction between an alkene, bromine, and water produces a halo hydrant, specifically a bromo hydron, with hydroxyl and bromine groups placed on the more and less substituted carbons, respectively. Due to the chirality of the secondary carbon, this process can yield a mixture of stereoisomers through an electrophilic addition mechanism.

Transcript

in this video we're gonna talk about the reaction between an alkene and bromine in the presence of water so this reaction is going to produce a product known as a halo hydrant but for this example more specifically a bromo hydron now there's two carbons that are of interest in this reaction the primary carbon in the double bond and the secondary ca... Read More

Key Insights

• 😇 The reaction between an alkene and bromine in the presence of water forms a halo hydrant, specifically a bromo hydron.
• 🫀 Selective distribution of the hydroxyl group and bromine atom occurs on the more substituted secondary carbon and the less substituted primary carbon, respectively.
• ❓ Stereoisomers can be obtained due to the chirality of the secondary carbon, resulting in a potential mixture of products.
• 💦 Water acts as a nucleophile, preferentially attacking the secondary carbon despite the greater accessibility of the primary carbon.
• 👊 The reaction proceeds through an electrophilic addition mechanism, involving the alkene attacking the bromine atom, forming a cyclic intermediate.
• 💦 The mechanism continues with water acting as a nucleophile, attacking the secondary carbon, and an additional water molecule abstracting a proton to yield the halo hydrogen product.
• 🙃 The reaction exhibits anti-addition stereochemistry, with the hydroxyl group and bromine atom positioned on opposite sides of the product.

Summary & Key Takeaways

• The reaction between an alkene and bromine in water produces a halo hydrant, specifically a bromo hydron, with distinct product distributions on the primary and secondary carbons.

• The more substituted secondary carbon gains a hydroxyl group, while the less substituted primary carbon gains a bromine atom as the product of this VG o selective reaction.

• Stereochemistry plays a role, with the secondary carbon being chiral, resulting in a potential mixture of stereoisomers.