An Overview of Organic Reactions

6 Using Curved Arrows in Polar Reaction Mechanisms 

7 Describing a Reaction Equilibria, Rates, and Energy Changes 

9 Describing a Reaction Energy Diagrams and Transition States 

11 A Comparison Between Biological Reactions and Laboratory Reactions A Deeper Look— Where Do Drugs Come From  

To understand both organic and biological chemistry, it s necessary to know not just what occurs but also why and how chemical reactions take place. In this chapter, we ll start with an overview of the fundamental kinds of organic reactions, we ll see why reactions occur, and we ll see how reactions can be described. Once this background is out of the way, we ll then be ready to begin studying the details of organic chemistry. 

Protein kinase A catalyzes the phosphorylation of various amino acids in proteins. 

All chemical reactions, whether they take place in the laboratory or in living organisms, follow the same rules. Reactions in living organisms often look more complex than laboratory reactions because of the size of the biomolecules and the involvement of biological catalysts called enzymes, but the principles governing all reactions are the same. 

Addition reactions occur when two reactants add to form one product, with no atoms left over. 

Elimination reactions occur when a single reactant splits into two products. 

Substitution reactions occur when two reactants exchange parts to yield two new products. 

A reaction mechanism describes the bonds broken and formed in a chemical reaction, and accounts for all reactants and products. 

Thomson JOW Throughout this chapter, sign in at www.thomsonedu.com for online self-study and interactive tutorials based on your level of understanding. 

Online homework for this chapter may be assigned in Organic OWL. 

Thomson yo. V Click Organic Interactive to classify organic reactions by examining reactants and products. 

When first approached, organic chemistry can seem like a bewildering collection of millions of compounds, dozens of functional groups, and an endless number of reactions. With study, though, it becomes evident that there are only a few fundamental ideas that underlie all organic reactions. 

Organic chemical reactions can be organized broadly in two ways—by u h kinds of reactions occur and by how reactions occur. Let s look first at f -. kinds of reactions that take place. There are four general types of organ , reactions additions, eliminations, substitutions, and rearrangements. 

An example of an addition reaction that we ll be studying soon is the reac tion of an alkene, such as ethylene, with HBr to yield an alkyl bromide  

Elimination reactions are, in a sense, the opposite of addition reac tions. Eliminations occur when a single reactant splits into two products  

Thomson- Throughout this chapter, sign in at www.thomsonedu.com for 

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Chapter 5, An Overview of Organic Reactions—A new Section 5.11 comparing biological reactions and laboratory reactions has been added. 

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