Question

Predict the product of the following reaction:

A. $\text{C}{{\text{H}}_{\text{2}}}\text{CHO}$
B.

C.

D.

Answer 1

Hint: The name of the reaction which is mentioned in the question is Wittig reaction. We can determine the product accordingly.

Complete step-by-step answer:
The Wittig reaction is a chemical reaction of an aldehyde or ketone with a triphenyl phosphonium ylide to give an alkene and triphenylphosphine oxide. It is widely used in organic synthesis for the preparation of alkenes.

The procedure in the Wittig reaction can be divided into two arep. In the first step, a phosphorus ylide is prepared by treating a suitable phosphonium salt with a base. In the second step the ylide is reacted with a substrate containing a carbonyl group to give the desired alkene.

As we can see that the product of the reaction that we can obtain is :

So the correct answer to the question is Option C.

Additional Information:
Occasionally it is also stated that, Wittig reaction is a reversible reaction. This statement is based on the procedure to provide carbonyl compound and phosphorane as a possible product. Such a reaction is known as the retro- Wittig reaction.
The most important uses of ylides in synthesis comes from their reactions with aldehydes and ketones, which are initiated in every case. Covalent bonding of the nucleophilic alpha carbon to the electrophilic carbonyl carbon.

Note: The formation of a phosphine oxide with a strong phosphorus and oxygen bond is the driving force for the classical Wittig reaction, but is wasteful and can put problems during purification. The limiting reagent in the Wittig reaction is triphenylphosphine.