Question

Question: What is the major product of each of the following reactions?

a.

b.

c.

d.

Short answer

Answer

a.

b.

c.

d.

Step-by-step solution

Explanation

The reactivity of aldehydes and ketones to the bases or reducing agents is based on the strength of the base. On the basis of the strength of the base used, the reaction can be distinguished as direct addition or as conjugate addition.

Subpart (a)

The major product of the reaction is shown below.

The Sodium cyanide is a weak base which favours the conjugate addition of the compound. Hence the major product will be cyano ketone and not an alcohol.

Subpart (b)

The major product of the reaction is shown below.

The Sodium borohydride is a reducing agent which will convert the cyclic ketones to alcohols. The ethanol is used as proton donors and solvent. The steric hindrance at beta carbon favours the direct addition.

Subpart (c)

The major product of the reaction is shown below.

The methyl magnesium bromide is a griginard reagent that will convert the ketones to alcohol. The methyl anion will attack the carbonyl centre to carry out the reaction. The ethanol is used as proton donors and solvent.

Subpart (d)

The major product of the reaction is shown below.

The Sodium borohydride is a reducing agent, can be used to reduce ketone easily in presence of double bond. The product obtained is an alcohol. The ethanol is used as proton donors and solvent.