How to Study Organic Chemistry
Most students consider organic chemistry to be one of the most difficult
courses that they take during their college career. Some consider it to be
challenging but fun (much like a game of chess can be) but others find it to
be impossibly difficult. The material can be mastered and is, in fact, not
The first difficulty that students encounter is the amount of information
that they are expected to learn. Organic chemistry is a very vigorous field
and much has already been discovered about organic compounds and their
reactions. Many organic text books are now about 1400 pages long. You cannot
expect to learn all this material without investing considerable time and
effort in studying. The pace of the course is brisk and allowing yourself to
fall behind in your studying will spell doom for most students.
Unlike general chemistry, the introductory organic courses (355 and 356)
contain little math. What then, does this vast volume of information consist
of? What are organic chemists interested in knowing and what do they know?
First, organic chemists are interested in the structure of organic
molecules. Your previous study of bonding (particularly covalent bonding)
will be reviewed and used extensively in this course. Organic chemists are
also very interested in the three dimensional shapes of molecules. The
branch of organic chemistry that deals with three dimensional shape is
called stereochemistry and will be a very important part of the course.
Second, organic chemists are very interested in chemical reactions. By the
end of the second course (356), you will have learned hundreds or even
thousands of reactions. In learning these reactions, you will want to know
what products will be obtained if two compounds are mixed under a given set
of conditions and also what kinds of reagents can be used to cause certain
types of reactions to occur.
Third, for many reactions we will study, the details of how the reactions
occur are known. When a reaction occurs one must first know what reagents
were used as starting materials and what the final products are. The
conversion of the starting materials to the products will involve either
breaking bonds, making bonds or both. The detailed sequence of which bonds
are broken and formed, in what order, and the stereochemical relationships
of these bonds is called a mechanism for the reaction.
Understanding mechanisms is the key to modern organic chemistry. Although we
will be studying hundreds or even thousands of reactions, these reactions
occur via only a few fundamental mechanistic pathways. It is the recognition
of the mechanistic similarities between different reactions that allows
organic chemistry to be readily understood. Many students who find organic
chemistry impossibly difficult never appreciate this. It is as if you were
given a copy of the New York City phone book that had been cut into pieces
containing one name each and asked to put the names in the order in the
book. Based on experience with some students in organic chemistry, a
surprising number would get a complete phone book, attempt to memorize it,
and then attempt to put the names in the order of the list they had
memorized. This is the reason that a surprising number of students find
organic chemistry impossibly difficult. Just as learning the alphabet and
the rules for alphabetization will help in assembling the phone book,
understanding mechanisms will help make sense of the thousands of facts that
comprise organic chemistry.
Your text book is organized primarily by types of compounds. Each type of
compound will contain a specified substructure or functional group. For
example, all the compounds of the type called alcohols contain an -OH group
(the functional group for alcohols) bonded to a carbon atom. As we study
each type of functional group, you will find that each reacts by only a few
mechanistic paths and hence has a chemical "personality" of its own. Do not
treat mechanisms as just another thing to memorize. Organic chemistry is a
vast field and you must be able to see the forest for the trees. Mechanism
and structure provide a way of doing this.
Now let us suppose that you have learned the structures of organic
compounds, what reactions various compounds undergo, what reagents cause
certain types of reactions and have a good grasp of known mechanisms. Have
you mastered organic chemistry? Are you now an organic chemist? Do you
deserve an "A" in the course? Not yet! Working organic chemists do not just
repeat what is known. They use that knowledge to solve problems and discover
This course will be just as much about learning to solve problems and apply
the knowledge you have gained as it will be about becoming familiar with
what organic chemists have learned. An analogy would be a course in the game
of chess. In such a course you would be expected to play chess. A simple
knowledge of the rules, recognition of the pieces and a knowledge of what
moves each piece is allowed would not be enough. Similarly, in this course,
you will be required to use the knowledge you have gained in new and
creative ways (both in the homework and in the exams). Organic chemistry is
as much or more about learning to think in a chemical context as it is about
the context itself. The types of problems that organic chemists encounter
are many and varied. However, there are three types of problems that
commonly occur and that you will often have to solve.
The first of these is identifying an unknown substance. This can be done by
studying the reactions that the compound does or does not do. To solve this
type of problem, you must learn chemical reactions in the forward sense.
That is, you must know what will happen if two compounds are mixed. A second
approach to this type of problem is to identify the compound through
spectroscopy. Spectroscopy involves subjecting the molecule to some energy
source (there are several types commonly used) and determining how it
interacts with the energy source.
A second major type of problem encountered by organic chemists is that of
preparing (making) a given compound. To work synthesis problems, it is
useful to learn chemical reactions in a reverse sense. That is, if you need
to make a given type of compound, you must know what types of reactions and
what starting materials to use to get it. Often the compound to be
synthesized is complicated enough that it cannot be made in a single
reaction -- rather a series of reactions is needed. In such a multi-step
synthesis, it is often useful to work backwards. That is, one first thinks
of all the ways of preparing the final product even if they do not use
acceptable starting materials (allowed compounds in homework problems or
compounds that are available in the laboratory). If none of the routes
contains acceptable starting materials, you then devise syntheses of those
starting materials. This process is then repeated until you find a route
back to acceptable starting materials.
The third major type of problem is explaining how a reaction occurs. The
first step is to propose a reasonable mechanism. One then devises tests to
check the proposed mechanism. In this course, more emphasis will be placed
on proposing a reasonable mechanism than on devising tests to see if your
mechanism is correct. As we study the mechanisms of known reactions, you
will note that each functional group has characteristic ways in which it
reacts. In most of the problems you will encounter, the individual steps of
a proposed mechanism should be consistent with the known types of reactions
for that functional group. Although it is possible, that the reaction
involves a completely new and different kind of reactivity, it is much more
likely that the individual steps are similar to known reactions. This will
be true for two reasons:
1. Many homework and test questions will be at least somewhat related to
what we have done, and
2. Organic chemists have already discovered many of the fundamental types
of reactivity for the types of compounds we will be studying.
To master organic chemistry, you will need to study regularly and
systematically. The following technique is useful for many people:
1. Read ahead. When you come to class you should have read the material
that will be presented.
2. Work the problems in the chapters (as opposed to those at the end of
the chapters) as you read the material. Write out the answers on paper.
Even if the answers seem obvious, writing them down will help you
3. When working problems, work several problems before consulting the
answer book. If you look up each answer as you do the problem you
cannot help catching a glimpse of the answer to the next problem. The
result is that you are not really working the next problem.
4. The first few problems at the ends of the chapters are there to help
you to become familiar with the new material and to help you remember
it. Look up the answers as needed. Again, write out the answers.
5. Prepare a set of flash cards to help you remember the reactions. Design
these cards to help you remember reactions in both the forward and
backward sense. Organic chemistry is a very cumulative subject. At the
end of the second course (356) you will need to know to know the
material presented on the first day of the first course (355) just as
much as you will on the first exam. These cards will be invaluable for
reviewing. NOTE WELL: Using flash cards prepared by another student
will give you some benefits but much of the benefit of the flash cards
comes from you having to think about the reaction enough to prepare the
6. Solve the more challenging problems at the ends of the chapters. The
answers to most of these problems will not be obvious to you when you
first read the question. Do not give up too quickly. Do not consult the
answer book without making a determined effort to solve the problem on
your own. Many people can read an answer and understand it. Do not be
fooled into thinking you can solve problems because you understand the
answers when you see them. Write the solutions out on paper.
7. Regular study will pay off much better than last minute cramming. You
will get much better results by studying a hour each and every day as
opposed to several hours once or twice a week.
8. Before exams review your flash cards and problems. Get a good nights
sleep. You will be expected to solve new problems on the exams. If you
have studied regularly, being alert and relaxed will be more important
than last minute cramming. If you haven't studied regularly, you will
be in trouble either way.
[Department of Chemistry]