Advanced Organic Chemistry

7

Molecular Rearrangements

LEARNING OBJECTIVES

By the end of this chapter you should be familiar with

• How we can change the connectivity of an existing organic backbone by using reactions that result in skeletal rearrangements.
• Participation: nucleophiles are more efficient if they are already part of the molecule.
• Participation means acceleration and retention of stereochemistry and may mean rearrangement. Participating groups can have lone pairs of π electrons.
• Types of rearrangement. Carbocations often rearrange by alkyl migration.
• The mechanisms of rearrangements.
• Ring expansion and contraction by rearrangement and controlling rearrangements.
• Insertion of O, N, or C next to a ketone.

7.1 INTRODUCTION

There are two types of rearrangements: ...