Chemistry of the Carbonyl Group

A step-by-step approach to understanding Organic Reaction Mechanisms

Revised Edition

Timothy K. Dickens

Fellow and Director of Studies in Chemistry
Peterhouse, Cambridge

Stuart Warren

Retired Fellow
Churchill College, Cambridge

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Preface

Understanding the movement of electrons as a reaction takes place is perhaps the hardest general concept in Organic Chemistry. This is often referred to as ‘pushing curly arrows’. Once this concept has been grasped, it becomes possible to rationalise what is happening in a chemical reaction and predictions can start to be made. In Chemistry of the Carbonyl Group, five chemical reactions are explored. These are nucleophilic addition, nucleophilic substitution, nucleophilic substitution with complete removal of carbonyl oxygen, carbanions and enolisation. With these reactions, it is possible to design and build organic molecules from carbonyl compounds. The last section of the book covers this. This understanding of the processes behind reactions by extrapolation can be used to rationalise organic reactions involving heteroatoms such as nitrogen, phosphorus and sulphur. Other types of chemical reactions, such as electrophilic substitution and addition, become easy to comprehend.

It is the authors' firm belief that the most effective way to learn is by practice and interaction. With this in mind, the reader is asked to predict what would happen under a specific set of reaction conditions. The book is divided into frames. These frames pose a question and invite the reader to predict what will happen. Subsequent frames give the solution but then pose more questions to develop a theme further. Therefore, the book should be worked though with pen and paper.

The reactions of the carbonyl group are some of the first reactions that a student studying Chemistry at university will encounter. As such, this book should be tackled just before, or when, a student is starting Organic Chemistry. Indeed, at Peterhouse, first year Natural Science students taking Chemistry are encouraged to work through this book during the Christmas break. Students who do this make substantially faster progress with the Cambridge Organic Chemistry course during the Lent term. The book could also be used by gifted or curious sixth-form students who are keen to broaden their knowledge of Organic Chemistry beyond the A-level syllabus.

This book was first published in 1974. After some discussion, it was decided not to change the text substantially. The motivation was very much to improve the layout of the book; hence all the diagrams have been redrawn using ChemDraw and the text formatted using the text mark-up language . One area that it might have been appropriate to develop is a discussion of the frontier orbitals; this would lead to an understanding of why the “magic angle” of attack in nucleophilic addition¹^–³ is $c0x-math-001$ . However, this could be seen as an unnecessary distraction, depending on what other Chemistry topics the reader is already familiar with.

Timothy K. Dickens, Cambridge February 2018