Question

Question. Devise a synthesis of hexane-2,3-diol from propane as the only source of carbon atoms. You may use any other required organic or inorganic reagents.

Short answer

Answer

Step-by-step solution

Halogenation

The organic reactions involving the replacement of protons by halide ions are known as halogenation reactions.

Propane is chlorinated using chlorine molecules in the presence of light to give propyl chloride. It further undergoes dehydrohalogenation to form prop-2-ene. The alkene is brominated and then treated with alcoholic potassium hydroxide solution to form the corresponding prop-2-yne.

Formation of prop-2-yne

Alkylation

The organic reaction in which an alkyl group attacks a nucleophilic center is known as an alkylation reaction.

Prop-2-yne is deprotonated by reacting with the strong base sodium amide. It is alkylated to form hex-2-yne.

Alkylation of prop-2-yne

Reduction

Hex-2-yne is reduced in the presence of Lindlar’s catalyst to form hex-2-ene.

Reduction of Hex-2-yne

Dihydroxylation

Hex-2-ene undergoes dihydroxylation in the presence of osmium tetroxide to form the vicinal diol.

Dihydroxylation to form vicinal diol