PROBLEM 12.23 - Organic Chemistry

Question

Question: What alkyne (or diyne) yields each set of oxidative cleavage products?

a.

b.

c.

d.

Step-by-Step Solution

Answer

Answer

a.

b.

c.

d.

Oxidative cleavage

The oxidative cleavage of alkynes is done by reacting them with ozone. The cleavage leads to the formation of two acid groups when the alkyne is internal, and an acid group and carbon dioxide when the alkyne is terminal. 

The general reaction of a terminal alkyne and an internal alkyne subjected to ozonolysis is shown below:

Representation of oxidative cleavage of alkynes

Determination of alkynes or diynes

a. Since carbon dioxide is one of the products of oxidative cleavage, we can see that the products have been derived from a terminal alkyne

Determination of the alkyne that led to the following product

b.Since a single type of product is formed, the alkyne which has undergone the oxidative cleavage must be an internal alkyne with similar substitution on both sides.

Determination of the alkyne that led to the following product

c. The three products suggest that they have been produced from a compound having two alkyne groups, that is a diyne.

Determination of the alkyne that led to the following product

d. Since two -COOH groups are formed in a single compound, it can be assumed that the alkyne that has led to this product is present in a ring system and undergoes intramolecular ozonolysis

Determination of the alkyne that led to the following product