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Chapter 16 545
Copyright © 2017 Pearson Education, Inc.
79.
a.
O
O
O
O OH
H
NOH
OH
A
B
C
D
H
b.
+
(C
6
H
5
)
3
OH
A
B
C
D
Br
P
−
80.
Cl C C Cl
O O
Cl C C Cl
O O
−
O
C C Cl
O O
O
Cl
CH
3
S
CH
3
Cl
dimethylchlorosulfonium ion
+
+
CH
3
S
CH
3
O
−
C
O
C
O
−
O
Cl
CH
3
CH
3
CH
3
CH
3
S
+
S
+
81.
In the first step of each reaction, cyanide is eliminated because it is a weak base. Conjugate addition occurs
in the second step, again, because cyanide ion is a weak base.
a.
CHCH C N
CH
2
O H
HO
−
CHCH
CH
2
O
OH H
C N
CCH
2
CH
2
CH
N
HO
−
O
−
b.
CH
3
CCH
O H
HO
−
OH H
C N
−
HO
−
CH
2
C N
CH
3
CCH
O
CH
2
CH
3
CCH
2
CH
2
C
O
N
82.
We have seen that the Wittig reaction proceeds via a concerted
3
2
+
2
4
cycloaddition reaction.
R C CH
2
H
O P(C
6
H
5
)
3
O
H
CH
3
CH
2
C
P(C
6
H
5
)
3
−
CH
2
+
C CH
2
O P(C
6
H
5
)
3
H
R
+