How do you convert Benzaldehyde to Benzophenone in exactly two steps?

Question

Madison Anderson · Accepted Answer

You do a Grignard reaction followed by an oxidation.

Step 1: benzaldehyde + phenylmagnesium bromide → diphenylmethanol

Step 2: diphenylmethanol + chromyl chloride → benzophenone

You can use any reagent that converts a secondary alcohol to a ketone.

These include acidified potassium dichromate, pyridinium chlorochromate, and chromyl chloride.

Maya Allen · Answer

undefined To convert benzaldehyde to benzophenone in two steps, you can perform a Friedel-Crafts acylation followed by oxidation.

Step 1: Friedel-Crafts acylation of benzaldehyde with an acyl chloride, such as benzoyl chloride, in the presence of a Lewis acid catalyst, typically aluminum chloride (AlCl3). This will form the intermediate benzophenone.

Step 2: Oxidation of the intermediate benzophenone using an oxidizing agent, such as chromic acid (H2CrO4) or potassium permanganate (KMnO4), to convert it to benzophenone.

So, the two steps are:

1. Friedel-Crafts acylation of benzaldehyde with benzoyl chloride in the presence of AlCl3.
2. Oxidation of the intermediate benzophenone using an oxidizing agent like chromic acid or potassium permanganate.