chapter 121 carbonyl compounds ii: chapter 12. chapter 122 contents of chapter 12 structure of...
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Chapter 12 1
Carbonyl Compounds II:Carbonyl Compounds II:Chapter 12Chapter 12
Chapter 12 2
Contents of Chapter 12 Structure of Aldehydes and Ketones Naming Adehydes and Ketones Reactivity with Nucleophiles Hydration of Aldehydes and Ketones Acetals and Ketals Skip Grignard Reagents, Hydride
Reductions, Reactions With Amines, Conjugate Additions, and Biological Reactions
Chapter 12 3
Structure of Aldehydes and Ketones
An aldehyde A ketone
or
Chapter 12 4
Nomenclature of Aldehydes and Ketones IUPAC Nomenclature of Aldehydes
• Select as the parent compound the longest chain of carbon atoms that contains the functional group.
• For aldehydes, change the suffix –e of the parent name to –al.
• Aldehyde carbon is carbon 1.
Chapter 12 5
Nomenclature of AldehydesO
CCH2 H
CH
CH3
CH3
CCH3
CH3
CH2
CH2CH
O
CH
CCH
CH3
3-Methylbutanal
trans-3,7-dimethyl-2,6-octadienal
12
34
56
78
14 2
3
Chapter 12 6
Nomenclature of Aldehydes and Ketones IUPAC Nomenclature of Ketones
• Select as the parent compound the longest chain of carbon atoms that contains the functional group.
• For ketones, change the suffix –e of the parent name to –one.
• Number the chain so that the ketone group gets the lowest number.
Chapter 12 7
Nomenclature of Ketones
O
CCH3 CH3
O
CCH
CH2
CH3
CH2 CH3
CH3
propanone (acetone) 4-methyl-3-hexanone
Chapter 12 8
Nomenclature of Ketones
O
CH3 C
O
CH3
2-methylcyclohexanone acetophenone
Note: The IUPAC system retains some common names such as acetone and acetophenone.
Chapter 12 9
Common Names
The common name for an aldehyde is derived from the common name of the corresponding carboxylic acid by changing the suffix –ic to –aldehyde.
O
CH OH
O
CH H
O
CCH3 OH
O
CCH3 H
formic acid formaldehyde acetic acid acetaldehyde
Chapter 12 10
Common NamesCommon names for ketones are derived by naming the two alkyl or aryl groups attached to the carbonyl group, followed by the word ketone.
O
CCH2CH
CH3
CH3 CH3
ethyl isopropyl ketone
Chapter 12 11
Reactions of Aldehydes and Ketones Nucleophilic Addition
O
CR R
H NuO
CR
NuR
H
+
The more sterically-hindered the area around the carbonyl carbon is the less reactive the aldehyde or ketone is with nucleophiles
Chapter 12 12
Reactions of Aldehydes and Ketones Addition of Water
• AldehydesO
CH H
H C
OH
OH
H+ H2O
O
CCH3 CH3
CH3 C
OH
OH
CH3+ H2O
• Ketones
Chapter 12 13
Formation of Acetals and Ketals Addition of one molecule of alcohol to
an aldehyde forms a hemiacetal:
a hemiacetal
O CH3
HO
CCH3 H
CH3 C
H
OH
OCH3+
Chapter 12 14
Formation of Acetals and Ketals
Hemiacetals and hemiketals react further with alcohols to form acetals and ketals.
These reactions are acid catalyzed.
+ H2O
CH3 C
OH
OCH3
H
CH3 C
OCH3
OCH3
H
+ CH3OHH
1,1-dimethoxyethane (a dimethyl acetal)
a hemiacetal
Chapter 12 15
Formation of Acetals and Ketals
a hemiketal + H2O
CH3 C
OH
OCH2CH3
CH3
CH3 C
OCH2CH3
OCH2CH3
CH3
+ CH3CH2OHH
2,2-diethoxypropane (a diethyl ketal)
Chapter 12 16
Oxidation of Aldehydes and Ketones
Oxidizing agents commonly used to oxidize aldehydes to carboxylic acids are potassium permanganate and chromic acid
O
CR H
O
CR OH
KMnO4or H2CrO4