Q14P - Organic Chemistry (Mcmurry)

Question

What alcohols would give the following products on oxidation?

(a)  

(b) 

(c) 

Step-by-Step Solution

Answer

a. 

b.

c.

Step 1: Oxidation of alcohol

The oxidation of alcohol gives carbonyl-containing compounds like aldehyde, ketone, and carboxylic acid. From primary (${\text{1}}^{\text{o}}$) alcohol, aldehyde or carboxylic acid is formed. From secondary (${\text{2}}^{\text{o}}$) alcohol, a ketone is formed. But oxidation of tertiary alcohols does not occur because they do not react much with oxidizing agents.

Step 2: The alcohol needed to produce the product (a)

a.   

The given product is a ketone, and the alcohol needed for oxidation is secondary. We know that secondary alcohols yield ketones. Here, the reagent used for oxidation is ${\mathrm{CrO}}_{\mathrm{3}}/{\mathrm{H}}_{\mathrm{3}}{\mathrm{O}}^{\mathrm{+}}$.

Oxidation of alcohol

Step 3: The alcohol needed to produce the product (b)

b.

The given product is an aldehyde, and the alcohol needed for oxidation is a primary alcohol. We know that primary alcohol on oxidation using Periodinane/ ${\text{CH}}_{\text{2}}{\text{Cl}}_{\text{2}}$ gives an aldehyde.

Oxidation of alcohol

Step 4: The alcohol needed to produce the product (c)

c.

The given product is a cyclopentanone (ketone), and the alcohol needed for oxidation is cyclopentanol (secondary alcohol). So, when cyclopentanol is treated with ${\text{CrO}}_{\text{3}}{\text{/H}}_{\text{3}}{\text{O}}^{\text{+}}$, the product formed is cyclopentanone because secondary alcohols yield ketones.

Oxidation of alcohol