Chapter 19, Problem 51P

Interpretation Introduction

Interpretation:

Synthesis of the given compound Darvon, starting with ethyl phenyl ketone is to be outlined.

Concept introduction:

Grignard reagent reactions with carbonyl groups are treated as acid–base reactions.

The reaction of Grignard reagents with carbonyl groups yields secondary and tertiary alcohols. These reactions are two-step reactions. In the first step, nucleophilic addition of carbonyl group takes place because Grignard reagent, being nucleophilic, uses its lone pair of electrons to form a bond with a carbon atom. This results in the formation of an alkoxide ion which remains associated with $M{g}^{2+}$ and $X^{-}$.

In the second step, addition of aqueous HX causes the protonation of the alkoxide ion, which leads to the formation of the alcohol and $Mg{X}_2$.

Mannich reaction: Carbonyl groups capable of forming enol react with primary or secondary amine and formaldehyde to form a $\beta$-amino carbonyl compounds known as Mannich base.

Alcohols react with acetic anhydride to form esters via nucleophilic substitution reaction.