Q15P - Organic Chemistry (Mcmurry)

Question

What products would you expect from oxidation of the following compounds with ${\mathbf{CrO}}_3$  in aqueous acid? With the Dess-Martin periodinane?

1. 1-Hexanol
2. 2-Hexanol
3. Hexanal

Step-by-Step Solution

Answer

a. 

b.

c.

Step 1: Oxidation of alcohol

Oxidation of alcohols can be done using reagents like aqueous acid and Dess-Martin Periodinane. Dess-Martin Periodinane is used to oxidize primary alcohols to aldehydes, whereas secondary alcohols are oxidized to ketones.

Step 2: The product expected from the oxidation of 1-Hexanol with CrO 3 in aqueous acid and with Dess-Martin Periodinane

a.  The starting material is 1-Hexanol, and when it is treated with ${\text{CrO}}_{\text{3}}$  in an aqueous solution, 1-Hexanol gets oxidized and converted to Hexanoic acid. When 1-Hexanol is treated with Dess-Martin Periodinane, the primary alcohol is converted to aldehyde, and we get Hexanal as a product.

Oxidation of 1-Hexanol with ${\text{CrO}}_{\text{3}}$  in  aqueous acid and with Dess-Martin Periodinane

Step 3: The product expected from the oxidation of 2-Hexanol with CrO 3 in aqueous acid and with Dess-Martin Periodinane

b. The starting material is 2-Hexanol, and when it is treated with ${\text{CrO}}_{\text{3}}$  in an aqueous solution, 2-Hexanol gets oxidized and converted to Hexan-2-one. 

When 2-Hexanol is treated with Dess-Martin Periodinane, the product Hexan-2-one is formed. We know that the secondary alcohols are converted to a ketone by ketone using Dess-Martin Periodinane.

Oxidation of 2-Hexanol with ${\text{CrO}}_{\text{3}}$  in  aqueous acid and with Dess-Martin Periodinane

Step 4: The product expected from the oxidation of Hexanal with CrO 3 in aqueous acid and with Dess-Martin Periodinane

c. The starting material is Hexanal, and when it is treated with ${\text{CrO}}_{\text{3}}$  in an aqueous solution, the aldehyde group gets oxidized to carboxylic acid.

When Hexanal is treated with Dess-Martin Periodinane, the aldehyde group does not oxidize further, and no reaction is possible.

Oxidation of Hexanal with ${\text{CrO}}_{\text{3}}$ in aqueous acid and with Dess-Martin Periodinane