Chapter 17, Problem 17.1YT

Interpretation Introduction

Interpretation:

Each reacting species is to be labeled as either “electron rich” or “electron poor”. Appropriate curved arrows are to be drawn, and the type of the elementary step is to be named under the each reaction arrow for the given reaction.

Concept introduction:

A nucleophilic addition reaction involves a $\text{π}$ bond which has an atom that is relatively electron poor (i.e., electrophile), so it tends to undergo the addition of a nucleophile, which is electron rich. The most common polar $\text{π}$ bond that participates in nucleophilic addition reactions is the one in the carbonyl $\left(\text{C = O}\right)$ group. To avoid exceeding the octet on the $\text{C}$ atom attacked by the nucleophile, the $\text{π}$ bond is broken, and the pair of electrons from the $\text{π}$ bond becomes a lone pair on the more electronegative $\text{O }$ atom. The immediate product of nucleophilic addition is often a strong base because it possesses a relatively unstable negative charge, thus followed by proton transfer step. The complete nucleophilic addition step is shown by four curved arrows, two in nucleophilic addition step and two in proton transfer step.