Transcript Synthetic Applications of Enamines (p.960). Recall that the

Synthetic Applications of Enamines (p.960). Recall that the
reaction of a ketone with a 2° amines gives an enamine
(Ch. 17.11)
O
H+
N
- H+
N
+
N
H
ketone
or aldehyde
w/ -protons
-H2O
2Ў amine
Iminium ion
Enamine
Enamines are reactive equivalents of enols and enolates and
can undergo -substituion reaction with electrophiles
N
O
N
H
O
H
Reaction of enamine with -unsaturated ketones (Michael
reaction).
N
+
O
O
CH3
O
then H2O
H2O
N
N
O
N
O
O
CH3
N
O
H OH
Enamines react on the less hindered side of unsymmetrical ketones
O
O
H3C
N
H3C
+
N
H
CH3
then H2O
O
H3C
O
Type II Aldolase uses enamine chemistry
CH2OPO32O
HO
H
H
H
Lys
aldolase
OH
OH
CH2OPO32-
H
N
HO
H
H
CH2OPO32CHO
aldolase
H
H
O H
OH
+
OH
CH2OPO32-
O2C
CH2OPO32-
Asp
Lys
H
N
CH2OH
HO
H
D-glyceraldehyde3-phosphate
D-fructose1,6-bisphosphate
CH2OH
O
Lys
NH2
CH2OH
H2O
Lys
H
N
CH2OH
HO
H
H
Dihydroxyacetone
HO2C Asp