What Is the Oxymercuration Demercuration Reaction?

TL;DR

The oxymercuration demercuration reaction converts alkenes to alcohols by adding a hydroxy group to the more substituted carbon atom. It involves the formation of a cyclic mercurinium ion when the alkene reacts with mercuric acetate, followed by water attack on the more stable secondary carbon. Sodium borohydride then reduces the intermediate to replace the mercuric acetate with a hydrogen, yielding the final alcohol product.

Transcript

in this video we're going to talk about the oxymercuration demercuration reaction so consider this particular alkene we're going to react it with mercuric acetate with water and in a second step in a separate reaction sodium borohydride what do you think the major product of this reaction is going to be the end product will be an alcohol the alkene... Read More

Key Insights

• 👥 The oxymercuration demercuration reaction converts alkenes to alcohols by adding an OH group to the more substituted carbon.
• 💁 The reaction proceeds through the formation of a cyclic mercurinium ion.
• 💦 The choice of primary or secondary carbon for attack by water or methanol depends on the stability of the resulting carbocation.
• 👥 Sodium borohydride is used in the second step to replace the mercuric acetate group with a hydrogen.

Questions & Answers

Q: What is the major product of the oxymercuration demercuration reaction?

The major product of the reaction is an alcohol, with the OH group added to the more substituted carbon atom of the alkene.

Q: How does the mechanism of the oxymercuration demercuration reaction work?

In the mechanism, the alkene attacks mercuric acetate, forming a cyclic mercurinium ion. Water then attacks the secondary carbon of the mercurinium ion, producing a more stable transition state. Sodium borohydride is used in the second step to replace the mercuric acetate group with a hydrogen.

Q: What happens if methanol is used instead of water in the oxymercuration demercuration reaction?

When methanol is used instead of water, the reaction produces an ether instead of an alcohol. The methoxy (OCH3) group can be added to either of the two secondary carbons of the alkene, resulting in a mixture of products.

Q: What is the major product for the reaction with methanol?

The major product for the reaction with methanol depends on which secondary carbon the methoxy group is added to. Both carbons of the double bond being secondary, the product can be a mixture of two different ethers.

Summary & Key Takeaways

• The oxymercuration demercuration reaction adds an OH group to the more substituted carbon atom of an alkene, producing an alcohol.

• The reaction involves the attack of the double bond on mercuric acetate, forming a cyclic mercurinium ion.

• Water then attacks the secondary carbon of the mercurinium ion, producing a more stable transition state.

• Sodium borohydride is used in the second step to replace the mercuric acetate group with a hydrogen, resulting in the final alcohol product.