21. Enolate Chemistry:Reactions at the Alpha-Carbon
Enolate Alkylation and Acylation
4PRACTICE PROBLEM
When an α-haloketone reacts with a hydroxide ion, a carboxylic acid is formed. This is known as a Favorskii reaction. Propose a suitable mechanism for the Favorskii reaction shown below. (Hint: The first step is deprotonation of the α-carbon that is not bonded to Br; the second step is the formation of a three-membered ring; and in the third step, HO− acts as a nucleophile.)
![](https://lightcat-files.s3.amazonaws.com/problem_images/7829628fc9b4b52c-1682945026894.jpg)
When an α-haloketone reacts with a hydroxide ion, a carboxylic acid is formed. This is known as a Favorskii reaction. Propose a suitable mechanism for the Favorskii reaction shown below. (Hint: The first step is deprotonation of the α-carbon that is not bonded to Br; the second step is the formation of a three-membered ring; and in the third step, HO− acts as a nucleophile.)