Preface

PREFACE TO THE STUDENT

Critical Thinking Approach

I want you to do well in organic chemistry. And even more, I would like you to understand why people become so interested in the field that they choose to make it their life's work. As a professor who taught Organic for 40 years, I recognized that probably less than 10% of the students in my Organic course were there of their own free will; almost all were taking Organic because it was required for something else. This makes for a tough audience. I wanted to engage my students and show them that Organic was not entirely dreary memorization of material out of a five-pound textbook. Organic can, not only be interesting, but also be important and relevant to their life, and can develop essential critical thinking skills that carry over to other fields.

It was more important for me to teach scientific critical thinking to my class of prospective biologists, biochemists, physicians, and chemists than to simply teach one more example of any reaction. Every student in my class needed to learn how to reason through complex problems. Organic Chemistry is full of these, and so the puzzles that my students would solve, in learning the scientific method, would be organic reactions. I asked my students to give me reasonable hypotheses for how a reaction works. As a puzzle to solve, organic reactions can teach critical thinking skills, which then can be applied to many other fields. I certainly want my physician to be great at critical thinking, for that is the essence of an accurate diagnosis.

Secrets to Success

This section gives you some of the secrets to success that have come from research on why some people succeed and others do not. Many books have been written on this topic, and ideas that will help you do well in Organic are summarized here. A long time ago, professor Lewis Terman of Stanford University developed the original IQ test and followed up on the youth that had top scores on that test. He found almost no correlation with how they turned out later in life. If smarts do not correlate with success, then what does? Recent research has turned up two character traits that can predict success, and the good news is that they are both learned and are not inherent. The learned traits are "mindset" and "grit," so let's look at each.

Mindset is the work of psychology professor Carol Dweck of Stanford University. She showed that people often had attitudes toward challenges that mostly fell into two categories. The "fixed mindset" group felt that their abilities were inherent, something they were born with, and not able to change. If they were "not good at math," then they would find another topic that came easily. If they failed, they took it personally, because it seemed they were not smart enough to succeed in that area. They often felt that working hard on a topic would not make up for a lack of an inherent gift. Therefore, they gave up easily.

Those with a "growth mindset" believed that ability was not inherent, but built through effort and practice. They realized that they could get better at something by working at it. For example, nobody becomes good a playing a musical instrument without a lot of practice. A growth mindset response to doing poorly at something was to work harder, not to quit. They just had not finished learning the topic or skill. If you look back at something you can do well, you will find that you spent a lot of time working at it. With a growth mindset, you can achieve much more than someone with a fixed mindset. Instead of saying, "I can't do it" just say, "I can't do it yet" and keep at it.

The second trait, "grit," is the work of psychology professor Angela Duckworth of the University of Pennsylvania. She defines grit as the perseverance and passion for long-term goals. Someone with the growth mindset needs grit to keep working at what they have not learned "yet." A good predictor of future success is the growth mindset, joined with the grit to not give up when things get difficult. Giving up is not a success strategy for anything.

The Challenge of Organic Chemistry

Organic Chemistry is a difficult topic; it is a cumulative year-long course, and is unlike any science course you have had before. Many other courses could be broken into separate modules with individual exams, and then it was off to a new topic. Organic Chemistry is one very long interconnected story. It is much more like a foreign language, where what you learn on day one is still needed at the end of the year. However, we tend to remember things that are recent and those things that we use a lot. The year-long nature of an Organic Chemistry course therefore requires much practice to retain the material for the length of the course. Cramming just does not work, but in the long run practice does.

This text uses 18 elemental mechanistic units, the electron flow pathways, to explain all organic reactions. These units are used over and over again and become the core of understanding how all the organic reactions work. The continual repetition of these basic units helps you retain the material and allows you to understand why these reactions occur. It is much easier to understand and retain information that makes conceptual sense.

An Expert Systems Approach to Organic Chemistry

Critical thinking requires us to ask, "Does this make sense?" If not, it's probably wrong. A believable scientific hypothesis has to be reasonable and pass cross-checks. We need to "generate and select" alternatives, which is the essence of a good critical thinking process. The map of all alternatives can be represented as a tree, what AI calls the "problem space." This text extracts the essence of the field: the conceptual tools, the general rules, the trends, the modes of analysis, and everything that one would use to construct an expert system. We need an efficient way to navigate this problem space from start to goal. For that, we need a small set of essential principles, or "control knowledge," to guide our route selection decisions toward an acceptable answer.

This text makes use of analysis tools common to expert systems, but rare in organic chemistry texts (such as flow charts as decision maps, correlation matrices to show all possible interactions, and simplified energy surfaces used as problem space maps). Good intuition comes from your automatic use of control knowledge to guide your decisions. If you can internalize this expert-system decision process, you will develop a chemical intuition and are well on your way to becoming an expert yourself. How to learn organic chemistry using this critical thinking approach is the essence of this book.

A Link to Biochemistry

For many students in a chemistry, biology, or premedical curriculum, the next course they will take after a year of Organic Chemistry is a year of Biochemistry, the organic chemistry of living cells. Since the cell is the world's best organic chemist, biochemistry has much to teach us about elegant reaction mechanisms. How does a cell manage to make all the compounds it needs from simple reactants, in water, at room temperature, and producing only the correct shape and not the useless mirror image? Organic Chemistry and Biochemistry are much more interesting when you think of them as an opportunity to learn the secrets of how life works. This text makes use of biochemical reaction mechanism examples to help you understand the magic and the elegance of the chemistry of living systems. It is just a taste of the things to come in a biochemistry course. You can see why physicians need to know organic and biochemistry, for if you can understand how a living system works, you might be able to repair it when things start to go wrong. I wish you success in this endeavor.

TO THE INSTRUCTOR

Unique Decision-Based Approach Expanded

This third edition provides students with something that they cannot get anywhere else: a chemical intuition based on learning and internalizing a cross-checked-decision process. An important part of the scientific method is the ability to postulate a reasonable hypothesis. This text teaches students how to write reasonable reaction mechanisms, and assumes only a general chemistry background. This text provides tools for handling large amounts of information. It emphasizes the "why?" of organic chemistry in order to help make sense of all the material.

To be able to teach students to make good decisions, we need to teach "control knowledge," which is the essence of a good intuition. These are checks of reasonability that include, among other things: stability trends, compatibility with the media pH, evaluation of energetics, and similarity to known processes. In addition to using flow charts to illustrate the problem analysis process, the third edition increases the use of energy surfaces as problem space maps to help with illustration of these concepts, while continuing the rigorous mechanistic approach to organic chemistry.

Originating with the first edition of this text was the concept of mechanisms being built from a limited number of elementary electron flow pathways, and that learning to assemble these pathways in a reasonable manner is all that is necessary to master mechanisms in organic chemistry. The impressive advantage that a decision-based approach has over memorization is that it engages...