91Ó°ÊÓ

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 $\mathrm{Î\pm }$-carbon should be the same as the leaving group of ester.

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

Preparation of compound (a)

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

Preparation of compound (b)