Question

What type of nucleophilic substitution (\( \text{S}_\text{N}1 \) or \( \text{S}_\text{N}2 \)) occurs in the hydrolysis of 2-Bromobutane to form \( (+-) \)-Butan-2-ol? Give reason.

Hint:

In \( \text{S}_\text{N}1 \) reactions, the rate-determining step is the formation of a carbocation intermediate. This intermediate can be attacked from either side, leading to racemization of the product.

Answer 1

Step 1: The reaction proceeds via an \( \text{S}_\text{N}1 \) mechanism, characterized by the formation of a planar carbocation. This carbocation intermediate can be attacked by the nucleophile from either face, resulting in product racemization. The depicted reaction illustrates the formation of the carbocation intermediate in an \( \text{S}_\text{N}1 \) process: \[ \text{CH}_3\text{CH}_2\text{C(Br)}\text{H}_2 \rightarrow \text{CH}_3\text{C}(\text{+})\text{H}_2 \] This mechanistic pathway inherently leads to racemization.