Question

Question: Draw a stepwise mechanism for the following reaction.

Short answer

Answer

The given reaction proceeds by the following mechanism:

Addition of bromine and water molecule

Formation of 1-bromopropanone

Step-by-step solution

Step-by-Step SolutionStep 1: Reaction of acetylene with halogens

The alkynes react with halogens in the same way as the alkenes.

Alkynes react with halogens to form additional products. The addition of one mole leads to the formation of trans dihalide. The trans dihalide then reacts with the second mole to form the tetrahalide.

The addition of halogens in the presence of water leads to the formation of ketones.

Stepwise mechanism of the given reaction

The first step for the given reaction involves the addition of halogen to the acetylene molecule and results in the formation of a cyclic intermediate.

The water molecule then acts as a nucleophile and leads to the formation of carbocation intermediate, which is resonance stabilized.

Addition of bromine and water molecule

Formation of 1-bromopropanone