Question

Draw the major organic product of the reaction. Show the stereochemistry, if applicable. Omit byproducts such as water or bromide ion.

Answer 1

Concepts and reason

A compound is given with a reagent in the reaction and the product of the reaction with the correct stereochemistry needs to form. As hydroxide ion is given which is a strong nucleophile therefore, the reaction will follow the elimination mechanism.

Fundamentals

A haloalkane can reacts with a nucleophile to undergo elimination reaction and result in the formation of an alkene.

The general reaction is as follows:

Elimination reaction can be classified as ${\rm{E - }}1$ and ${\rm{E - 2}}$ . In ${\rm{E - }}1$ elimination reaction the reaction completes in two step and involves the formation of carbocation intermediate. In haloalkane, the order of reactivity for the ${\rm{E - }}1$ elimination is, $3^\circ > 2^\circ > 1^\circ > {\rm{C}}{{\rm{H}}_3}$ like the stability of carbocation.

In E-2 elimination reaction the reaction takes place in one step through the formation of a transition state. In haloalkane, the order of reactivity for the ${\rm{E - 2}}$ elimination is, $3^\circ < 2^\circ < 1^\circ < {\rm{C}}{{\rm{H}}_3}$ .

Show the product of the reaction following the elimination mechanism by the abstraction of proton from the alpha-carbon by the nucleophile as shown below:

Show the product of the reaction following the elimination mechanism by the abstraction of proton from the other alpha-carbon by the nucleophile as shown below:

Compare the stability of both the products and write the major organic product as shown below:

Ans:

Hence, the major product of the reaction is as follows:

Answer 2