But - 2 - yne on reductive ozonolysis produces

Options

A. butane - 2, 3 - dione
B. butanone
C. propanone
D. both propanone and butanone

Answer

To solve the problem of what but-2-yne produces on reductive ozonolysis, we can follow these steps:

### Step 1: Understand the Structure of But-2-yne
But-2-yne is an alkyne with the following structure:
- It has four carbon atoms.
- The triple bond is located between the second and third carbon atoms.

The structural formula can be written as:
\[ \text{CH}_3 - \text{C} \equiv \text{C} - \text{CH}_3 \]

### Step 2: Ozonolysis Reaction
In ozonolysis, ozone (O₃) reacts with the alkyne. The reaction involves the formation of a cyclic ozonide intermediate, which then undergoes cleavage.

### Step 3: Cleavage of the Ozonide
Upon cleavage of the ozonide, we will generate carbonyl compounds. For but-2-yne, the cleavage will yield two molecules of a carbonyl compound.

### Step 4: Reduction of the Ozonide
In reductive ozonolysis, the ozonide is reduced typically using a reducing agent such as zinc (Zn) in the presence of water. This step converts the ozonide into ketones.

### Step 5: Identify the Products
For but-2-yne, the ozonolysis will produce two molecules of acetone (2-propanone) as the final product. The structure of acetone is:
\[ \text{CH}_3 - \text{C}(=O) - \text{CH}_3 \]

### Final Answer
Thus, the products of the reductive ozonolysis of but-2-yne are two molecules of acetone.

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