Carbonyl Compounds Aldol Condensation PPT Chemistry Class 12

 Page 1


CARBONYL COMPOUNDS
ALDOL CONDENSATION
1
Page 2


CARBONYL COMPOUNDS
ALDOL CONDENSATION
1 2
Carbonyl Condensation Reactions
TheAldol Reaction
• In the aldol reaction, two molecules of an aldehyde or
ketone react with each other in the presence of a base
to form a ?-hydroxy carbonyl compound.
Page 3


CARBONYL COMPOUNDS
ALDOL CONDENSATION
1 2
Carbonyl Condensation Reactions
TheAldol Reaction
• In the aldol reaction, two molecules of an aldehyde or
ketone react with each other in the presence of a base
to form a ?-hydroxy carbonyl compound.
3
TheAldol Reaction
• The mechanism of the aldol reaction occurs in three
steps.
Carbonyl Condensation Reactions
Page 4


CARBONYL COMPOUNDS
ALDOL CONDENSATION
1 2
Carbonyl Condensation Reactions
TheAldol Reaction
• In the aldol reaction, two molecules of an aldehyde or
ketone react with each other in the presence of a base
to form a ?-hydroxy carbonyl compound.
3
TheAldol Reaction
• The mechanism of the aldol reaction occurs in three
steps.
Carbonyl Condensation Reactions
4
TheAldol Reaction
• The aldol reaction is a reversible equilibrium, so the
position of the equilibrium depends on the base and the
carbonyl compound.
• ¯OH Is the base typically used in an aldol reaction.
Although with ¯OH only a small amount of enolate is
formed, this is appropriate because the starting
aldehyde is needed to react with the enolate in the
second step of the reaction.
• Aldol reactions can be carried out with either aldehydes
or ketones. With aldehydes, the equilibrium usually
favors products, but with ketones the equilibrium favors
the starting materials. However, there are ways of
driving the equilibriumto the right.
Carbonyl Condensation Reactions
Page 5


CARBONYL COMPOUNDS
ALDOL CONDENSATION
1 2
Carbonyl Condensation Reactions
TheAldol Reaction
• In the aldol reaction, two molecules of an aldehyde or
ketone react with each other in the presence of a base
to form a ?-hydroxy carbonyl compound.
3
TheAldol Reaction
• The mechanism of the aldol reaction occurs in three
steps.
Carbonyl Condensation Reactions
4
TheAldol Reaction
• The aldol reaction is a reversible equilibrium, so the
position of the equilibrium depends on the base and the
carbonyl compound.
• ¯OH Is the base typically used in an aldol reaction.
Although with ¯OH only a small amount of enolate is
formed, this is appropriate because the starting
aldehyde is needed to react with the enolate in the
second step of the reaction.
• Aldol reactions can be carried out with either aldehydes
or ketones. With aldehydes, the equilibrium usually
favors products, but with ketones the equilibrium favors
the starting materials. However, there are ways of
driving the equilibriumto the right.
Carbonyl Condensation Reactions
5
TheAldol Reaction
• Recall that the characteristic reaction of aldehydes and
ketones is nucleophilic addition. An aldol reaction is a
nucleophilic addition in which an enolate is the
nucleophile.
Carbonyl Condensation Reactions
Figure 24.1
The aldol reaction —An example
of nucleophilic addition