Transcript 4. Addition Reactions of Aldehydes and Ketones

Chapter 14 Aldehydes, Ketones,
and Chiral Molecules
14.4
Addition Reactions of Aldehydes
and Ketones
General, Organic, and Biological Chemistry
Copyright © 2010 Pearson Education, Inc.
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Addition Reactions
When a polar molecule adds to the carbonyl group
of an aldehyde or ketone,
 the negative part of the added molecule bonds to the
positive carbonyl carbon
 the positive part of the added molecule bonds to the
negative carbonyl oxygen
General, Organic, and Biological Chemistry
Copyright © 2010 Pearson Education, Inc.
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Addition Reactions (continued)
General, Organic, and Biological Chemistry
Copyright © 2010 Pearson Education, Inc.
3
Acetal Formation
Acetals
 are the product of two alcohols adding to the carbonyl
groups of aldehydes and ketones.
General, Organic, and Biological Chemistry
Copyright © 2010 Pearson Education, Inc.
4
Hemiacetal Formation
A hemiacetal is
 an intermediate produced when one alcohol adds to
the carbonyl group of an aldehyde or ketone
 usually unstable and difficult to isolate
General, Organic, and Biological Chemistry
Copyright © 2010 Pearson Education, Inc.
5
Cyclic Hemiacetals
In glucose, a cyclic hemiacetal between the C═O group
and the —OH forms a stable, six-atom ring
General, Organic, and Biological Chemistry
Copyright © 2010 Pearson Education, Inc.
6
Learning Check
Identify each as a 1) hemiacetal or 2) acetal.
General, Organic, and Biological Chemistry
Copyright © 2010 Pearson Education, Inc.
7
Solution
Identify each as a 1) hemiacetal or 2) acetal.
1) hemiacetal
2) acetal
General, Organic, and Biological Chemistry
Copyright © 2010 Pearson Education, Inc.
8
Learning Check
Draw the condensed structural formula of the acetal
formed by adding CH3OH to butanal.
General, Organic, and Biological Chemistry
Copyright © 2010 Pearson Education, Inc.
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Solution
Draw the condensed structural formula of the acetal
formed by adding CH3OH to butanal.
General, Organic, and Biological Chemistry
Copyright © 2010 Pearson Education, Inc.
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