Question

Propose a Williamson synthesis of 3-butoxy-1,1-dimethylcyclohexane from 3,3-dimethyl-cyclohexanol and butan-1-ol.

Short answer

When Butan-1-ol reacts with tosyl chloride in the presence of pyridine. it gets converted into butyl tosylate in the first step. Pyridine acts as a base here and it abstracts the proton of the hydroxyl group forming oxygen anion which attacks on the tosyl group of tosyl chloride and as a result, chloride ion leaves as a leaving group.

Reaction of butan-1-ol with tosyl chloride

Step-by-step solution

Reaction of butan-1-ol with tosyl chloride

When Butan-1-ol reacts with tosyl chloride in the presence of pyridine. it gets converted into butyl tosylate in the first step. Pyridine acts as a base here and it abstracts the proton of the hydroxyl group forming oxygen anion which attacks on the tosyl group of tosyl chloride and as a result, chloride ion leaves as a leaving group.

Reaction of butan-1-ol with tosyl chloride

Williamson ether synthesis

Williamson ether synthesis works best when the nucleophile attacks at primary or methyl carbon. In the next step, when 3,3-dimethyl-cyclohexanol reacts with sodium, it forms sodium salt of 3,3-dimethyl cyclohexanol which then reacts with butyl tosylate (which was prepared in first step) and forms 3-butoxy-1,1-dimethylcyclohexane (which is our required product).

Williamson ether synthesis