Question

Draw the products of the following reactions:

a.

b.

Short answer

a.

b.

Step-by-step solution

Step-by-Step SolutionStep 1: Michael's reaction

In a conjugate addition reaction, when the nucleophile is an enolate ion, that reaction is called a Michael reaction. If one of the reactants in Michael's reaction is ester, the base used for removing $\mathrm{\alpha }$-carbon should be the same as the leaving group of ester.

The product formed in reaction (a)

(a) The starting compounds are $\mathrm{\alpha },\mathrm{\beta }$-unsaturated amide and $\mathrm{\beta }$-keto ester. In the first step, the base removes a proton from the $\mathrm{\alpha }$-carbon of the $\mathrm{\beta }$-keto ester. In the second step, the enolate ion is added to the $\mathrm{\beta }$-carbon of the $\mathrm{\alpha },\mathrm{\beta }$-unsaturated amide, and at last, the role="math" localid="1652540005184" $\mathrm{\alpha }$-carbon is protonated. The product formed is shown in the reaction below.

Preparation of compound (a)

The product formed in reaction (b)

(b) The starting compounds are ester and $\beta$- keto nitriles compounds. The base removes a proton from the $\alpha$-carbon in the $\beta$-keto nitriles in the first step. In the second step, the enolate ion is added to the $\beta$-carbon of the ester. The product formed is shown below in the reaction.

Preparation of compound (b)