Question

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Draw the major organic product (other than ethanol) formed in the following reaction

Draw the major organic product (other than ethanol) formed in the following reaction

Answer 1

Concepts and reason

The problem is based on the concept of elimination reaction in alkyl halide. Mechanism of elimination can be or depending upon the stability of carbocation.

The order of stability of carbocation is as follows:

Here, and is tertiary, secondary and primary carbocation respectively

For primary carbocation, is favored as iut does not require the formation of carbocation and for secondary and tertiary carbocation is favored which involves carbocation formation.

Fundamentals

In elimination, final product is alkene which is formed following Saytzeff rule which states that more substituted alkene is more stable.

Mechanism for the reaction will be E1 and formation of alkene take place by following Saytzeff rule.

In first step, elimination of bromide ion takes place resulting formation of more stable tertiary carbocation. After the formation of carbocation in second step, base abstract hydrogen atom from carbon with less number of hydrogen atoms (Saytzeff rule) resulting formation of more substituted alkene that is 2-methylbut-2-ene.

The mechanism of the reaction will be as follows:

There could be another possibility but the product (2-methylbut-1ene) so formed is less substituted alkene therefore less stable or minor product.

Ans:

Major organic compound formed is as follows: