Download Worked Example 14.1

Worked Example 14.1 Naming Organic Compounds: Alcohols
Give the systematic name of the following alcohol, and classify it as primary, secondary, or tertiary:
Analysis
First, identify the longest carbon chain, and number the carbon atoms beginning at the end nearer
the —OH group. The longest chain attached to the —OH has 5 carbon atoms:
Next, identify and number the hydroxyl group and the substituents. Finally, write the name of the compound.
Solution
Since the —OH group is bonded to a carbon atom that has three alkyl substituents, this is a tertiary alcohol.
Fundamentals of General, Organic, and Biological Chemistry, 7e
John McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. Peterson
© 2013 Pearson Education, Inc.
Worked Example 14.2 Organic Reactions: Dehydration
What products would you expect from the following dehydration reaction? Which product will be major and which
will be minor?
Analysis
Find the hydrogens on carbons next to the OH-bearing carbon, and rewrite the structure to emphasize
these hydrogens:
Then, remove the possible combinations of —H and —OH, drawing a double bond each —H and —OH could be
removed:
Finally, determine which alkene has the larger number of alkyl substituents on its double-bond carbons and is
therefore the major product.
Fundamentals of General, Organic, and Biological Chemistry, 7e
John McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. Peterson
© 2013 Pearson Education, Inc.
Worked Example 14.2 Organic Reactions: Dehydration
Continued
Solution
Fundamentals of General, Organic, and Biological Chemistry, 7e
John McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. Peterson
© 2013 Pearson Education, Inc.
Worked Example 14.3 Organic Reactions: Dehydration
Which alcohol(s) yield 4-methyl-2-hexene on dehydration? Are there any other alkenes that arise from dehydration
of these alcohols?
Analysis
The double bond in the alkene is formed by removing —H and —OH from adjacent carbons of the
starting alcohol. This removal occurs in two possible ways, depending on which carbon is bonded to
the —OH and to the —H.
Solution
Dehydration of 4-methyl-2-hexanol yields 4-methyl-2-hexene as the major product, along with 4-methyl-1-hexene.
Dehydration of 4-methyl-3-hexanol also gives 4-methyl-2-hexene but as the minor product, along with 3-methyl-3hexene as the major product.
Fundamentals of General, Organic, and Biological Chemistry, 7e
John McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. Peterson
© 2013 Pearson Education, Inc.
Worked Example 14.4 Organic Reactions: Oxidation
What is the product of the following oxidation reaction?
Analysis
The starting material is a primary alcohol, so it will be converted first to an aldehyde and then to a
carboxylic acid. To find the structures of these products, first redraw the structure of the starting
alcohol to identify the hydrogen atoms on the hydroxyl-bearing carbon:
Next, remove 2 hydrogens, one from the —OH group and one from the hydroxyl-bearing carbon. In their place,
make a C=O double bond. This is the aldehyde product that forms initially. Finally, convert the aldehyde to a
carboxylic acid by replacing the hydrogen in the —CH=O group with an —OH group.
Solution
Fundamentals of General, Organic, and Biological Chemistry, 7e
John McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. Peterson
© 2013 Pearson Education, Inc.
Worked Example 14.5 Molecular Structures: Drawing Ethers and Alcohols
Draw the structure for 3-methoxy-2-butanol.
Analysis
First identify the parent compound, then add numbered substituents to appropriate carbons in the
parent chain.
Solution
The parent compound is a 4-carbon chain with the —OH attached to C2.
The 3-methoxy substituent indicates that a methoxy group (—OCH3) is attached to C3.
Finally, add hydrogens until each carbon atom has a total of four bonds.
Fundamentals of General, Organic, and Biological Chemistry, 7e
John McMurry, David S. Ballantine, Carl A. Hoeger, Virginia E. Peterson
© 2013 Pearson Education, Inc.