Question

Draw the major organic product for the following reactions:

Draw the major organic product for the following reaction: Draw the major organic product for the following reaction:

Answer 1

Concepts and reason

This problem is based on the reaction of alkyl halides.

is a two-step nucleophilic substitution reaction in which a nucleophile substitutes a halogen atom to form new products through the formation of a carbocation. In the first step the halogen atom is the leaving group that leaves carrying with it the shared electron pair, to form an intermediate carbocation. The nucleophile then attacks the electron deficient carbocation to from the product.

Fundamentals

A tertiary carbocation is more stable than secondary which in turn is more stable than primary carbocation.

In the mechanism, the carbocation formed in the first step can rearrange to form a more stable carbocation by shifting of a hydride, methyl or phenyl group to the electron deficient carbon. The stable carbocation then reacts with the nucleophile to form the major product.

(a)

The chemical reaction in the formation of carbocation is shown below:

The mechanism showing the methyl shift in order to form more stable tertiary carbocation is shown below:

Attack of nucleophile on carbocation is shown below:

(b)

The chemical reaction in the formation of carbocation is shown below:

The mechanism showing the methyl shift in order to form more stable tertiary carbocation is shown below:

Attack of nucleophile on carbocation is shown below:

Ans: Part a

The structure of major organic product formed is as follows: