Question

What starting materials are needed to prepare each alkene by a Wittig reaction? When there are two possible routes, indicate which route, if any, is preferred.

a.

b

c.

Short answer

a.

b.

c.

Step-by-step solution

Wittig reaction

It involves the formation of an alkene by the treatment of a ketone or an aldehyde with ylide. The ylide is termed Wittig reagent.

Formation of product

a.

The reaction is shown below.

Synthesis in a

b.

The reaction is shown below.

Synthesis in b

c.

The reaction is shown below.

Synthesis in c