Question

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

Answer 1

General guidance

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:

Haloalakne Nucleophile alkene

Elimination reaction can be classified as [{ m{E - }}1] and [{ m{E - 2}}]. In [{ m{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 [{ m{E - }}1] elimination is, [3^circ > 2^circ > 1^circ > { m{C}}{{ m{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 [{ m{E - 2}}] elimination is, [3^circ < 2^circ < 1^circ < { m{C}}{{ m{H}}_3}].

Step-by-step

Step 1 of 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:

Br OH

Explanation | Hint for next step

In elimination reaction, the nucleophile abstract the proton from the carbon which is adjacent to the carbon containing the halogen atom and the halogen atom being a good leaving group leave the system as shown below:

Br: \u0491\u043e\u043d

Step 2 of 3

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:

Br OH

Explanation

In elimination reaction, the nucleophile abstract the proton from the carbon which is adjacent to the carbon containing the halogen atom and the halogen atom being a good leaving group leave the system as shown below:

Br:

Step 3 of 3

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

OH Major product Minor product

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

\u043e\u043d Major product More substitted alkene Minor product Less substitted alkene

Explanation

More substituted alkene is more stable due to hyperconjugation. Hence, the major product will be the one which contains more substituted alkene as shown below:

OH Major product

Answer

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

OH Major product

Answer only

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

OH Major product