Chapter 9, Problem 9.5YT

Interpretation Introduction

Interpretation:

The groups that contribute to significant steric hindrance in each of the three bases shown are to be identified.

Concept introduction:

A bulky base is one that has large groups attached to the carbon that is in turn bonded to the basic atom (one with a lone pair). These bulky groups prevent the approach of an electrophilic atom or group other than a proton. In other words, they sterically hinder the basic atom from forming a bond with any electrophilic atom other than a proton. These groups must, therefore, be considerably larger than a hydrogen atom.