61E - Organic Chemistry (Mcmurry)

Question

Propose a synthesis of the anti-inflammatory drug Fenclorac from phenyl cyclohexane. 

Step-by-Step Solution

Answer

The Fenclorac synthesis from phenyl cyclohexane can be proposed.

Step 1: The alcohol gets converted into aldehyde

The benzene can be brominated for the yield of bromophenylcyclohexane. The Grignard reagent can be produced by converting bromide when it is treated with ether. Then it reacts with formaldehyde to form primary alcohol. The alcohol will be converted into aldehyde to oxidize Dess-Martin periodinane. A chlorine can be substituted into an aldehydic group as-CHO is meta-directing.

Step 2: Process for the yield of Fenclorac

The aldehyde treatment with NaCN will yield a cyanohydrin when hydrolyzed with hydroxy acid. The hydroxyl group can be replaced using Cl when treated with SOCl₂ for the Fenclorac yield.

Step 3: Fenclorac synthesis from phenycyclohexane

The synthesis can be shown as,