Question

Propose structures for hydrocarbons that give the following products

on oxidative cleavage by KMnO₄ or O₃ :

2. 
3. 
4. 
5. 

Short answer

Alkynes can be cleaved by oxidizing agents like KMnO₄ or ozone. Triple bonds comprise less reactivity than double bonds and produce low yields.

1. 
2. 
3. 
4. 
5. 

Step-by-step solution

Oxidative cleavage

Alkynes can be cleaved by oxidizing agents like KMnO₄ or ozone. Triple bonds comprise less reactivity than double bonds and produce low yields.

The reactant that gives the products in (a)

(a)The products, heptanoic acid and carbon dioxide are produced when oct-1-yne is treated with KMnO₄ and H₃O⁺. So the hydrocarbon is oct-1-yne. The reaction can be given as:

Hydrocarbon that produces the products in (a)

The reactant that gives the products in (b)

(b)The products benzoic acid and acetic acid are produced when prop-1-yn-1-ylbenzene reacts with KMnO₄ and H₃O⁺. So, the hydrocarbon is prop-1-yn-1-ylbenzene. The reaction can be given as:

Hydrocarbon that produces the products in (b)

 The reactant that gives the products in (c)

(c)The product decane-1,2-dioic acid is obtained when cyclodecyne undergoes cleavage by KMnO₄ and H₃O⁺. So the hydrocarbon is cyclodecyne. The reaction can be given as:

Hydrocarbon that produces the products in (c)

The reactant that gives the products in (d)

(d)The products acetaldehyde, 4-oxopentanoic acid and carbon dioxide are obtained when 5-methylhept-5-en-1-yne undergoes cleavage in the presence of KMnO₄ and H₃O⁺ . So the hydrocarbon is 5-methylhept-5-en-1-yne. The reaction can be given as:

Hydrocarbon that produces the products in (d)

The reactant that gives the products in (e)

(e)The hydrocarbon that produces the products 2,7-dioxoheptanoic acid and carbon dioxide is 1-ethynylcyclohex-1-ene. The reaction can be given as:

Hydrocarbon that produces the products in (e)