For more than 40 years, I have taught courses on reaction mechanisms in organic chemistry at undergraduate and graduate level throughout my academic career. During my classes, I realized that many students do not like organic chemistry and most believe that it is a lesson to be memorized. I have searched for a way to change this idea. Organic chemistry is a systemic field like mathematics and hence memorizing is not necessary. Students need to know the reaction mechanisms in organic chemistry and understand their many common points. For example, there are many condensation reactions and students usually try to memorize them. However, they all have the same mechanisms and students must learn this. Starting from that point, I decided to write a book about these reaction mechanisms and emphasize the points common to them.

In my lectures, I always tell the students that chemical reactions occur because of a reaction between an acid and a base (a Lewis acid and a Lewis base). Therefore, they should learn the acid/base concepts very well in order to understand chemistry. For this, they need to determine in which part of a molecule the electron density is increased or decreased. They can achieve this by fully understanding the factors that influence electron density. In other words, they should have a firm grasp of the mesomeric effect and the inductive effect. A student who comprehends these concepts can predict what product will be formed as a result of a chemical reaction and will not rely on memorization. Therefore, I included these concepts in the first part of this book. I explained the mesomeric effect and inductive effect through detailed examples.

Another disadvantage faced by students is that most of them cannot perceive organic compounds in a three-dimensional structure. For this, the concept of hybridization needs to be explained clearly and understood fully. Then, the students can imagine the three-dimensional structure and understand how isomers are formed in some reactions. Therefore, I explained hybridization in detail in the introduction part.

A further aspect of organic chemistry that confuses students is oxidation/reduction. For this, they should know oxidation numbers well and not mix them up with formal charges. This subject is examined in detail in the book, along with examples.

After this introduction, the students begin to grasp the reactions quickly. I included substitution, elimination, and addition reactions as the essential ones. A student who has taken a one-semester organic chemistry course can easily comprehend these issues. Then, I examined the reactions derived from the carbonyl group. I emphasized that essential reactions are significant in this subject, which is very broad. With a good grasp of the carbonyl group's polarization and the acidity of the alpha proton, students can understand the carbonyl group and realize how simple condensation reactions are.

In the part on aromaticity, I first explained classical reactions after the concepts of aromaticity. Here too, I tried to find common points mechanistically. After these chapters, I moved on to more advanced topics that both undergraduate and graduate students can follow.

The chemistry of intermediates is extremely important mechanistically. A student who has learned the chemistry of the intermediate well can fully understand organic chemistry. For this reason, I focused extensively on carbocations, carbanions, radicals, and carbenes, which are involved as intermediates during the reactions. A student who can deal with these issues will have a full understanding of all the rearrangements.

The book's final chapters are devoted to the Woodward–Hoffmann rules and modern C–C couplings. These are subjects written for both undergraduate and graduate students.

In summary, in this book, I tried to discourage students from relying on memorization by drawing attention to reaction mechanisms' common points. I hope that this book will be useful to both undergraduate and graduate students at any time.

There may be one name on the front cover, but every book is the result of the hard work of many people. I gratefully acknowledge the following professors for their helpful critiques of this book at many stages during its development. They devoted a tremendous amount of time to review this book and made valuable suggestions.

I would also like to thank the following professors for reviewing the chapters and providing feedback on developing new features. I sincerely appreciate all of their suggestions.

The author gratefully acknowledges the critical readings by the students Aslıcan Özdemir, Başak Karagöllü, Fevzi Can İnyurt, Flora Mammadova, Furkan Melih Günay, İpek Öktem, İpek Savaş, Kübra Erden, and Semin Özsinan, members of Dr. Çağatay Dengiz's group at the Middle East Technical University. Finally, I thank all my students, at both Middle East Technical University and Atatürk University, for their positive interactions over the years, which have guided me in creating this book. I also thank Mr. Russell Fraser for proofreading.

Although every effort has been made to eliminate all possible errors, it is likely that some typographical mistakes remain in the text. I would welcome comments from the readers, particularly those that point out mistakes so that they can be corrected, as well as suggestions for additions or other changes that will make the book more valuable to the reader.

This book of extensive scope could not have been produced without the excellent support I have had from many people at John Wiley-VCH. I would particularly like to thank the Editorial Director, Dr. Gudrun Walter, and the Executive Commissioning Editor, Dr. Elke Maase. They have been of great assistance at every stage of production. I am deeply grateful to my managing editor, Katherine Wong, who was always ready to do whatever was needed to make this book the best that it could be.

I would also thank Content Refinement Specialist Abisheka Santhoshini, and others involved in the typesetting.

I would also like to thank my daughter Gülşah, my son-in-law Onur, and son Berkay for their continued support and encouragement during the writing process.

Finally, my wife Jale offered unwavering patience and support and understood why I was writing. There is no adequate way to express my appreciation. Jale provided a comfortable environment that enabled me to write this book.

Metin Balcı was born in Erzurum, Turkey, in 1948. He received his “Diplom Chemiker” degree in 1972, followed by a PhD degree in 1976 from the University of Cologne, where he worked with Professor Emanuel Vogel. He did postdoctoral work with Professors Harald Günther (Siegen, Germany), Waldemar Adam (Puerto Rico), and W. M. Jones (Florida).

In 1980, he joined the Department of Chemistry at Atatürk University and he became a full professor there in 1987. He spent one year (1986) at the University of Cologne and one year (1996–1997) at Auburn University (USA) as a guest professor. In 1997, he moved to Middle East Technical University in Ankara because of its reputation.

Metin Balcı has received several prizes, including the 1983 “Junior Research Prize” and the “Scientific Award” in 1989 from the Scientific and Technical Research Council of Turkey. Furthermore, he was awarded the “Science Prize” by the Science and Technology Foundation in 1990 and the “Chemistry Prize” by the Chemistry Foundation and the “Science Prize” by the Ministry of Culture in 1991. He has received the Best Teacher of the Year Award (2000, 2003, and 2004) and the Distinguished Teaching Award at Middle East Technical University. His name was given to the NMR labs in the Department of Chemistry, Atatürk University, in 2010. He is an elected member of the Turkish Academy of Sciences.

His main research interest involves the synthesis of cyclitols, endoperoxides, cyclic strained compounds, bromine chemistry, and heterocyclic compounds. He has published 280 scientific papers and he retired in 2015. He has also published books entitled Basic ¹H and ¹³C NMR Spectroscopy (426 pages, Elsevier, January 2005 and Turkish version in 2000 by METU Press). The Reaction Mechanism in Organic Chemistry (in Turkish, 2008) and an autobiography, Science Rising from the East, in 2019 (in Turkish) were published by the Turkish Academy of Sciences.

Metin Balcı has always maintained a strong interest in the great outdoors. He enjoys observing nature, hiking, skiing, and reading, as well as world travel.