Introduction

Welcome to Organic Chemistry II For Dummies. We’re certainly happy you decided to delve further into the fascinating world of organic chemistry. It’s a complex area of chemistry, but understanding organic chemistry isn’t really that difficult. It simply takes hard work, attention to detail, some imagination, and the desire to know. Organic chemistry, like any area of chemistry, isn’t a spectator sport. You need to interact with the material, try different study techniques, and ask yourself why things happen the way they do.

Organic Chemistry II is a more intricate course than the typical freshman introductory chemistry course, and you may find that it’s also more involved than Organic I. You may actually need to use those things you learned (and those study habits that you developed) in Organic I to be successful in Organic II. But if you work hard, you can get through your Organic II course. More importantly, you may grow to appreciate the myriad chemical reactions that take place in the diverse world of organic chemistry.

About This Book

Organic Chemistry II For Dummies is an overview of the content covered in the second half of a typical college-level organic chemistry course. We’ve made every attempt to keep the material as current as possible, but the field of chemistry is changing ever so quickly — new reactions are always being developed. The basics, however, stay the same, and that’s where we concentrate our attention.

While you flip through this book, you see many chemical structures and reactions. Much of organic chemistry involves knowing the structures of the molecules involved in organic reactions. If you’re in an Organic Chemistry II course, you made it through the first semester of organic chemistry, so you probably recognize many of the structures, or at least the functional groups, from your previous semester’s study.

Tip If you bought this book just to gain general knowledge about a fascinating subject, try not to get bogged down in the details. Skim the chapters. If you find a topic that interests you, stop and dive in. Have fun learning something new.

If you’re taking an organic chemistry course, you can use this rather inexpensive book to supplement that very expensive organic chemistry textbook. Then, when you complete your course, you can put it on your bookshelf as a conversation piece, alongside Chemistry For Dummies, by your intrepid author, John Moore (Wiley), The Doctor Who Error Finder, by R.H. Langley (McFarland), and A Brief History of Time, by Stephen Hawking (Bantam Dell). Or you can look forward to adding a copy of Biochemistry For Dummies, also by the authors of this book (Wiley), beside it.

Conventions Used in This Book

We’ve organized this book in a logical progression of topics; your second semester organic chemistry course may progress similarly. In addition, we set up the following conventions to make navigating this book easier:

Italics introduce new terms that you need to know.

Bold text highlights keywords within a bulleted list.

We make extensive use of illustrations of structures and reactions. While you read, try to follow along with the associated figures, whether they be structures or reactions.

Foolish Assumptions

We assume — and we all know about the perils of assumptions — that you’re one of the following:

A student taking a college-level organic chemistry course.

A student reviewing organic chemistry for some type of standardized exam (the MCAT, for example).

An individual who just wants to know something about organic chemistry.

If you fall into a different category, you’re special — and we hope you enjoy this book, too.

Icons Used in This Book

If you have ever read other For Dummies books (such as the wonderful Chemistry For Dummies or Biochemistry For Dummies, written by the two authors of this book and published by Wiley), you recognize the icons we use. The following five icons can guide you to certain kinds of information:

Remember This icon is a flag for those really important things that you shouldn’t forget while you go deeper into the world of organic chemistry.

Realworld The Real World icon points out information that has a direct application in the everyday world. These paragraphs may also help you understand the bigger picture of how and why organic mechanisms are in place.

Tip We use this icon to alert you to a tip on the easiest or quickest way to learn a concept. Between the two of us, we have over 70 years of teaching experience. We picked up a few tricks along the way, and we don’t mind sharing.

Warning The warning icon points to a procedure or potential outcome that can be dangerous. We call it our Don’t-Try-This-At-Home icon.

Technical Stuff We try to avoid getting too technical throughout this book (believe it or not), but every now and then, we can’t help but throw something in that’s a little more in-depth than you might need. You can’t hurt your education by just skipping it.

Beyond the Book

In addition to the material in this printed book, go to www.dummies.com to find a Cheat Sheet with study tips and exam-taking advice. To access this resource, simply type Organic Chemistry II For Dummies Cheat Sheet in the search box on Dummies.com.

Where to Go from Here

The answer to this question really depends on your prior knowledge and goals. Like with all For Dummies books, this one attempts to make all the chapters independent so that you can dive right into the material that’s causing you trouble without having to read other chapters first. If you feel comfortable with the topics covered in Organic Chemistry I, feel free to skip Part I of this book. If you want a general overview of organic chemistry, skim the book. And when you find a topic that interests you or one in which you really need help, take a deeper plunge into the chapter that deals with that topic.

And for all of you, no matter who you are or why you’re reading this book, we hope you have fun reading it and that it helps you to understand and appreciate organic chemistry.

Part 1

Brushing Up on Important Organic Chemistry I Concepts

IN THIS PART …

Refresh yourself on the basics from Organic Chemistry I.

Get up to speed on mechanisms and how to push electrons around with those curved arrows.

Review the structure, nomenclature, synthesis, and reactions of alcohols and ethers.

Tackle conjugated unsaturated systems.

Get the how-to on spectroscopic techniques, from the IR fingerprints to NMR shifts.

Chapter 1

Organic Chemistry II: Here We Go Again!

IN THIS CHAPTER

Bullet Reviewing the material you learned in Organic I

Bullet Previewing what you find out in Organic II

If you’re looking at this chapter, it’s probably because you’re getting ready to take the second half of organic chemistry, are in the midst of Organic II, or you’re trying to figure out what Organic II covers in time to change your major from pre-med to art history. In any respect, you probably successfully completed Organic Chemistry I. Many of the study techniques (and coping mechanisms) you learned that helped you do well in Organic I are helpful in Organic II. The two primary things to remember are

Never get behind.

Carbon has four bonds.

In this book we use larger, more complex molecules than you may have encountered in Organic I. We chose to do this because, firstly, that’s the nature of Organic II — larger and more complex molecules. Secondly, many of you will be taking biochemistry at some point, and to succeed in that subject you need to become comfortable with large, involved molecules. (If you do take biochemistry, be sure to check out Biochemistry For Dummies by John T. Moore and Richard H. Langley [Wiley]. We understand the authors are really great guys.)

To get you started, this chapter does a quick review of the topics commonly found in Organic I, and then gives an overview of what we cover in Organic II.

While you read over what you specifically need from Organic I, make sure you note anything you feel weak about so that you can do a quick review now.

Recapping Organic Chemistry I

In Organic I you learned that organic chemistry is the study of carbon compounds. Until the mid-1800s, people believed that all carbon compounds were the result of biological processes requiring a living organism. This was called the vital force theory. The synthesis (or formation) of urea from inorganic materials showed that other paths to the production of carbon compounds are possible. Many millions of organic compounds exist because carbon atoms form stable bonds to other carbon atoms. The process of one type of atom bonding to identical atoms is catenation. Many elements can catenate, but carbon is the most effective, with apparently no limit to how many carbon atoms can link together. These linkages may be in chains, branched chains, or rings, providing a vast number of compounds.

Carbon is also capable of forming stable bonds to a number of other elements, including the biochemically important elements hydrogen, nitrogen, oxygen, and sulfur. The latter three elements form the foundation of many of the functional groups you studied in Organic I, while hydrogen is in nearly every organic compound.

Intermolecular forces

You learned about intermolecular forces in Organic I. Intermolecular forces (forces between chemical species) are extremely important in explaining the interaction between molecules. Intermolecular forces that you saw in Organic I and see again in Organic II include dipole-dipole interactions, London, hydrogen bonding, and sometimes ionic interactions.

Dipole-dipole forces exist between polar regions of different molecules. The presence of a dipole means that the molecule has a partially positive (δ+) end and a partially negative (δ–) end. Opposite partial charges attract each other, whereas like partial charges repel.

Hydrogen bonding, as the name implies, involves hydrogen. This hydrogen atom must be bonded to either an oxygen atom or a nitrogen atom. (In nonbiological situations, hydrogen bonding also occurs when a hydrogen atom bonds to a fluorine atom.) Hydrogen bonding is significantly stronger than a normal dipole-dipole force, and is much stronger than London dispersion forces, the forces between nonpolar molecules due to the fluctuations of the electron clouds of atoms or molecules. The hydrogen bonded to either a nitrogen or oxygen atom is strongly attracted to a different nitrogen or oxygen atom. Hydrogen bonding may be either intramolecular or intermolecular.

In organic reactions, ionic interactions may serve as intermolecular or intramolecular forces. In some cases, these may involve metal cations, such as Na+, or anions, such as Cl–. Cations may include an ammonium ion from an amino group, such as RNH3+. The anion may be a carboxylate ion, such as RCOO– from a carboxylic acid. The oppositely charged ions attract each other very strongly (stronger than the other intermolecular interactions).

Functional groups

Carbon is an extremely versatile element because it can form many different compounds. Most of the compounds you see have one or more functional groups, which contain atoms other than carbon and hydrogen and/or double or triple bonds, and define the reactivity of the organic molecule.

In Organic I you probably started with the hydrocarbons, compounds of carbon and hydrogen, including the alkenes and alkynes that contained double and single bonds, respectively. Then you probably touched on some of the more common functional groups, such as alcohols and maybe even some aromatic compounds.

Reactions

You encountered many reactions in Organic I. Every time you encountered a different functional group, you had a slew of reactions to learn. Reactions that told how the functional group could be formed, common reactions that the functional group underwent — reactions, reactions, and more reactions.

Two of the most important ones you learned were substitution and elimination reactions: SN1, SN2, E1, and E2. We hope you learned them well because you’ll be seeing them again quite