Preface to the third edition

In its first incarnation, this book grew out of the conviction that highly developed practical skills, as well as a thorough grasp of theory, are the hallmark of a true organic chemist and that chemistry is illustrated more vividly by experiment than from a book or lecture course, when the facts can seem abstract and sterile. The original aim, therefore, was to produce a book containing safe, interesting experiments of varying complexity, together with all the associated technical instruction, which could be used in a variety of courses from the elementary to the advanced. With the goal of enthusing budding and current organic chemists, experiments were chosen to be more than just recipes for preparing a particular compound, or manipulative exercises. Rather, each experiment was associated with some important reaction, an interesting mechanism, or an underlying principle, without forgetting the practical skills to be acquired along the way. Within the constant and overriding demands for safety, the range of experiments was chosen to illustrate as many techniques and to cover as much organic chemistry as possible, in order to link up with lecture courses, and provide depth and relevance to the whole teaching programme.

So that was in the years running up to 1989 when the first edition appeared, to be followed by a second edition in 1999. Time has moved on, and this third edition of Experimental Organic Chemistry, arguably long overdue, has been born out of the recognition that much has happened in the field of organic chemistry since 1999, although the original aims espoused in the first edition still remain central.

Such progress has been made since 1989 that reactions and techniques that were once the domain of the specialist research laboratory - or indeed not even discovered when the first edition appeared - have now become commonplace in both academic and industrial environments - metal-catalysed cross-coupling reactions, metathesis, organocatalysis, microwave and flow chemistry are all now represented in the third edition. To this end, a new member has joined the writing team and it is doubtless that, without the professional ability, enthusiasm, verve and sheer determination to see the job finished by Dr Philippa Cranwell, this project would probably have withered and petered out. She is a very welcome addition to the team.

However, the third edition is not simply about the addition of new subject matter, but the removal of other material in recognition of the technical advances that have been made since this book was last updated. The almost immeasurable increase in computational power during the lifetime of this book has rendered much of the initial discussions of data storage and retrieval obsolete, as the power of the Internet reigns supreme and will only continue to evolve and gather force at an ever-increasing pace. As a result, most references to hardcopy data storage and retrieval have been removed, except for that last bastion of paper - the laboratory notebook - although it is recognized that, even here, its days are numbered.

If the Internet has changed for ever the way in which we obtain and exchange information, then technological advances combined with increased computing power have radically affected the way in which experimental data are measured and interpreted. This third edition contains expanded discussions of NMR and IR spectroscopic and mass spectrometric techniques that are now routine parts of the analytical arsenal of organic chemistry, while still retaining explanations of the fundamental principles of these techniques. UV spectroscopy is retained, even though it is recognized that this technique is rarely used in the research laboratory nowadays, except as a detection method in HPLC. So why have certain aspects of spectroscopic techniques been retained in the third edition? Quite simply, the more technology takes over, the more an analytical technique becomes a 'black box', so much so that the chemist may forget to question and challenge; accepting mutely, the data produced. Without a fundamental understanding and appreciation of a technique being used and its pitfalls and limitations, a scientist is treading on treacherous ground when carrying out spectroscopic analysis.

Nonetheless, some techniques described in the first edition and retained in the second have simply fallen out of practice and have been removed in recognition of standard practice in teaching and research laboratories at this time. However, it is not simply older practices that have been removed. In the second edition, microscale chemical techniques were included as, during that period, these were becoming popular in student teaching programmes in many universities. They now seem to have waned in popularity worldwide, so microscale methodology and experimental procedures pertaining to student experiments have been removed, although small-scale protocols useful at the research level have been retained.

As in the previous two editions, the book is divided into two main sections - the first surveying aspects of safety, apparatus, purification and spectroscopic techniques, and the recording and retrieval of data, and the second containing the experimental procedures and appendices. As a result of the need to include examples of more recent synthetic methodologies, the experimental section has increased to 104 experimental procedures from the 86 contained in the second edition, almost back to the 105 contained in the first edition. More importantly, the range and choice of illustrative experiments more closely reflect the experimental environment in which today's organic chemists operate, from the fundamental to the more esoteric. As before, the experimental procedures have been further subdivided into chapters covering 'functional group interconversions', 'carbon-carbon bond-forming reactions' and 'projects', but an additional chapter covering 'enabling technologies' - microwave and flow chemistry - has been included. We are indebted to Associate Professor Nicholas Leadbeater of the University of Connecticut for providing procedures for the flow chemistry protocols contained in this chapter, and the Moody group at the University of Nottingham for the microwave chemistry protocols. Above all, we have continued to include examples of most of the important reaction types at varying levels of experimental difficulty, so that a concerted series of experiments might be designed that is tailored to the specific teaching needs of a class or an individual student.

Safety in the laboratory is, as always, the paramount consideration when choosing or retaining an experiment, and we have attempted to minimize potential hazards by avoiding toxic materials wherever possible and by highlighting in the text any possible hazards at appropriate points of the procedure. In addition, the scale of each standard experimental procedure has been kept as small as is commensurate with the level of difficulty, to minimize any adverse consequences of an accident, in addition to lessening disposal problems and cost. Nonetheless, health and safety regulations worldwide have become complex and sometimes contradictory, so the advice always is to assess the risk and validate all procedures with the local health and safety guidelines before commencing any experimental work.

Following feedback over the past 25 years or so, the experiments in this third edition have been included for their reproducibility and all have been independently assessed for such. Each experiment is preceded by a general discussion, outlining the aims and salient features of the investigation, and is followed by a series of problems designed to emphasize the points raised in the experiment. To emphasize safety aspects, make the greatest use of time available in the teaching laboratory and encourage forward planning, apparatus, instruments and chemicals required in the experiment are listed at the beginning of the procedure, together with an estimation of the amount of time necessary to complete the experiment. Extended periods of reflux or stirring have been avoided wherever possible and long experiments have been designed so that they have clear break points at roughly 3-hour intervals, indicated in margin notes in the procedure. The indicative degree of difficulty of each experiment is as follows:

1. Introductory-level experiments requiring little previous experience.
2. Longer experiments with the emphasis on developing basic experimental techniques.
3. Experiments using more complex techniques and spectroscopic analysis.
4. Research level.

Data on yields and melting points, useful hints and checkers' comments for each experiment, and guidelines for answers to all of the problems are available at the companion website: www.wiley.com/go/cranwell/EOC. Of course, almost all necessary data can be obtained from the Internet with a few clicks of a mouse or a few swipes of the finger. Nonetheless, some data tables are presented in appendices at the end of this book as we felt that these were likely to be of greatest use both to students working for their first degree and also to research workers.

In addition to those already mentioned, we would like to acknowledge others whose help has been fundamental in the production of this third edition. In alphabetical order, thanks go to Professor Matthew Almond (University of Reading), Professor Chris Braddock (Imperial College), Dr Geoff Brown (University of Reading), Professor Rainer Cramer (University of Reading), Dr Rob Haigh...