Question

Мар сар reagents and conditions necessary to efficiently carry out the following muti-skom NaOH, acetone rom the starting material on the left to the product on the right. Do not worry a 1. LDA, THF, -78 C, 2. NaOH, H20, heat PPh3, n-Buli 1. ethyl acetoacetate, 2. NaoÉt, HOE 1. NaOET, HOEt, methyl vinyl ketone H2, Pd-C (one equiv.)

Answer 1

Mechanism-

First the ethylacetoacetate forms an enolate ion and attacks the aldehyde. The enolate ion is formed by the abstraction of methylene proton.

The methylene proton is the more acidic than the methyl protons because the resulting carbanion will be stabilised by two electron withdrawing group.

The product then undergoes decarboxylation to give a β- hydroxy ketone. In presence of base, the elimination of OH occurs.

Then the reduction of the resulting compound gives the final product.