One of the point intresting and useful aspects on stereochemisty is the stuyd of what happens to optically active molecules when they react. The product isolated from the reaction of a chiral starting mterial can tell us a great deal about the reaction mechanism.
The given reaction is an example of which type of reaction ?
`D-underset(C_(6)H_(5)) underset(|)overset(C_(3)H_(7)) overset(|)C-ONa+Cl-overset(O)overset(||)S-Cloverset("ether")toD-underset(C_(6)H_(5))underset(|)overset(C_(3)H_(7))overset(|)C-Cl+SO_(2)+HCl`

Options

A. `SN2`
B. `SN1`
C. `SNi`
D. `SN1`

Answer

To determine the type of reaction represented by the given equation, we need to analyze the components and the mechanism involved. Here’s a step-by-step breakdown of the solution:

### Step 1: Identify the Reactants
The reaction involves a chiral compound (an alkoxide) reacting with thionyl chloride (SOCl₂). The reactants are:
- An alkoxide (D-C₆H₅-C(OH)(C₃H₇))
- Thionyl chloride (SOCl₂)

### Step 2: Understand the Reaction Mechanism
The reaction mechanism can be classified based on how the nucleophilic substitution occurs. In this case, the alkoxide (which has a lone pair of electrons) attacks the sulfur atom in thionyl chloride. This leads to the formation of an intermediate.

### Step 3: Formation of the Intermediate
When the alkoxide attacks the sulfur, the sulfur atom becomes positively charged, and the chlorine atom is displaced. The lone pair of electrons from the oxygen atom of the alkoxide forms a bond with sulfur, resulting in a cyclic intermediate.

### Step 4: Nucleophilic Attack and Inversion of Configuration
In the next step, the chlorine ion (Cl⁻) attacks the carbon atom from the opposite side (backside attack), leading to an inversion of configuration at the chiral center. This is characteristic of certain nucleophilic substitution reactions.

### Step 5: Identify the Products
The final products of the reaction are:
- An alkyl halide (D-C₆H₅-C(Cl)(C₃H₇))
- Sulfur dioxide (SO₂)
- Sodium chloride (NaCl)

### Conclusion
Based on the analysis, the reaction is classified as a **Substitution Nucleophilic Intramolecular (SNi)** reaction. This type of reaction is characterized by the nucleophile being part of the same molecule that is undergoing substitution, leading to a cyclic intermediate and inversion of configuration.

### Final Answer
The given reaction is an example of **SNi (Substitution Nucleophilic Intramolecular)** reaction.

---