Question

Hydroxide replaces \(\mathrm{OH}\) groups via an \(\mathrm{S}_{\mathrm{N}}^{2}\) reaction.

Short answer

Question: In an S_N2 reaction involving a hydroxide ion as the nucleophile, describe the step-by-step process that leads to the formation of the final product with an inverted stereochemistry at the reaction center. Answer: In an S_N2 reaction with hydroxide ion, the step-by-step process includes: (1) identifying the substrate and nucleophile, with the substrate containing a suitable leaving group, (2) formation of a transition state as the nucleophile approaches the substrate, (3) inversion of stereochemistry due to the nucleophile attacking the central carbon while the leaving group departs simultaneously, known as "Walden Inversion," and (4) formation of the final product with a new functional group involving the hydroxide ion and an inverted stereochemistry at the reaction center.

Step-by-step solution

Understanding the S_N2 Reaction Mechanism

An S_N2 reaction is a nucleophilic substitution reaction that occurs in one step. In this reaction, the nucleophile (in this case, hydroxide ion \(\mathrm{OH}^{-}\)) approaches the substrate from the opposite side of the leaving group, leading to the inversion of the stereochemistry at the reaction center.

Identify the Substrate and Nucleophile

In this exercise, the nucleophile is the hydroxide ion (\(\mathrm{OH}^{-}\)), and the substrate will be a suitable molecule with a leaving group. In an S_N2 reaction, a good leaving group is necessary for the reaction to proceed.

Formation of the Transition State

As the nucleophile approaches the substrate, a transition state is formed where the nucleophile starts to form a bond with the substrate's central carbon while the leaving group's bond begins to break. The transition state is a high-energy state, and its stability determines the reaction progress.

Inversion of Stereochemistry

Since the S_N2 reaction occurs in a single step, the nucleophile attacks and forms the bond with the central carbon atom at the same time that the leaving group departs. This process leads to an inversion in the stereochemistry of the chiral center, known as the "Walden Inversion."

Formation of the product

After the nucleophile has formed a bond with the substrate's central carbon and the leaving group has departed, the product is formed with a new functional group involving the hydroxide ion. The stereochemistry at the reaction center is inverted as compared to the original substrate. In conclusion, the given exercise highlights an S_N2 reaction where a hydroxide ion replaces a leaving group through nucleophilic substitution, resulting in a stereochemical inversion at the reaction center. It is crucial to follow the step-by-step mechanism to understand the formation of the final product properly.