Organic Compounds Alkanes and Their Stereochemistry

Thomson Jt W Click Organic Interactive to learn how to recognize functional groups in organic molecules. 

According to Chemical Abslnu ls, the publictilion that abstracts and indexes the cliemical Ulerattire, there are more than 30 million known organic compounds. Fach of these compounds has its own physical jiroperties, such as melting jx int and boiling point, and each has its own chemical reactivity. 

Functional Groups with Carbon-Carbon Multiple Bonds 

Alkenes, alkynes, and arenes (aromatic compounds) all contain carbon-carbon multiple bonds. Alkenes have a double bond, alkynes have a triple bond, and arenes have alternating double and siiigle bonds in a six-membered ring of carbon atoms. Because of their structural similarities, these compounds also have chemical similarities. 

Carboxylic acid anhydride 0 0 II II O C / / -ok aiilmiride 0 0 II II CH3COCCH3 Ethanoic aniiydride 

Chemists have learned through years of experience that organic compounds can be classified into families according to their stmctural features and that the members of a given family often have similar chemical behavior. Instead of 40 million compounds with random reactivity, there are a few dozen families of organic compounds whose chemistry is reasonably predictable. We ll study tbe chemistry of specific families throughout much of this book, beginning in this chapter with a look at the simplest family, the alkanes. 

Why This Chapter Alkanes are relatively unreactive and not often involved in chemical reactions, but they nevertheless provide a useful vehicle for introducing some important general ideas. In this chapter, we ll use alkanes to introduce the basic approach to naming organic compounds and to take an initial look at some of the three-dimensional aspects of molecules, a topic of particular importance in understanding biological organic chemistry. 

The stmctural features that make it possible to classify compoimds into families are called functional groups. A functional group is a group of atoms within a molecule that has a characteristic chemical behavior. Chemically, a given functional group behaves in nearly the same way in every molecule it s a part of. For example, compare ethylene, a plant hormone that causes fmit to ripen, with menthene, a much more complicated molecule found in peppermint oil. Both substances contain a carbon-carbon double-bond functional group, and both therefore react with Br2 in the same way to give a product in which a Br atom 

Carboxylic acid 0 II / -ok acid 0 II CH3COH Ethanoic acid 

A membrane channel protein that conducts K+ ions across cell membranes. 

Functional groups are groups of atoms within a molecule that have a characteristic chemical behavior. 

The chemistry of every organic molecule is determined by its functional groups. 

Functional groups described in this text can be grouped into three categories  

Functional groups with carbon-carbon multiple bonds. 

Groups in which carbon forms a single bond to an electronegative atom. 

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CHAPTER 3 Organic Compounds Alkanes and Their Stereochemistry... 

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