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Chapter 16 525
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2.
+
H B
+
N
R
R
+
+
H
2
O
NR
2
OH
+
H B
NR
2
OH
H B
+
NHR
2
OH
+
B
OH
+
R
2
NH
+
O
+
R
2
NH
2
+
N
R
R
H H
-carbon
b.
The only difference is the first step of the mechanism: in imine hydrolysis, the acid protonates the
nitrogen; in enamine hydrolysis, the acid protonates the
b
-carbon.
33.
a.
O CH
3
CH
2
NH
2
NCH
2
CH
3
+
H
2
O
+
trace H
+
b.
O CH
3
CH
2
NH
N
+
H
2
O
CH
2
CH
3
+
CH
2
CH
3
CH
2
CH
3
trace H
+
c.
C
CH
3
O
+
CH
3
(CH
2
)
5
NH
2
C
CH
3
N(CH
2
)
5
CH
3
H
2
O
+
trace H
+
d.
C
CH
3
O
C
CH
3
N
H
2
O
NH
2
+
+
trace H
+
34.
A tertiary amine will be obtained because the primary amine synthesized by reductive animation will react
with the excess carbonyl compound, forming an imine that will be reduced to a secondary amine. The
secondary amine will then react with the carbonyl compound, forming an enamine that will be reduced to a
tertiary amine.
R
2
C O
+
NH
3
NaBH
3
CN
R
2
CHNH
2
R
2
CHNHCHR
2
(R
2
CH)
3
N
R
2
C O
R
2
C O
NaBH
3
CN
NaBH
3
CN
primary
amine
secondary
amine
tertiary
amine