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Chapter 9 335
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86.
a.
−
b.
c.
−
stabilized by electron delocalization
(resonance)
d.
CH
3
CH
2
C CH
2
CH
3
e.
stabilized by electron delocalization (resonance)
f.
CH
3
CHCHCH
3
CH
3
−
g.
CH
3
CCH
2
CH
3
CH
3
+
87.
He obtained only the elimination product because a tertiary alkyl halide does not undergo an
S
N
2
reaction.
Because of steric hindrance, only an E2 reaction occurs.
CH
3
CCH
3
CH
3
Cl
+
CH
3
CH
2
O
−
CH
3
C CH
2
CH
3
predominant product
Rather than a tertiary alkyl halide and a primary alkoxide ion, he should have used a primary alkyl halide
and a tertiary alkoxide ion. They will react in an
S
N
2
reaction to form the desired ether.
CH
3
CH
2
Cl
+
CH
3
CO
−
CH
3
CH
3
CH
3
COCH
2
CH
3
CH
3
CH
3
+
Cl
−
Although the Williamson ether synthesis (an
S
N
2
reaction) is the preferred way to synthesize an ether
because it gives higher yields, the ether also could be synthesized using an
S
N
1
reaction.
+
+
CH
3
CBr
CH
3
CH
3
CH
3
COCH
2
CH
3
HBr
CH
3
CH
3
CH
3
CH
2
OH
88.
a.
(CH
3
)
3
CBr
HO
−
H
2
O
C CH
2
CH
3
CH
3
+
Br
−
because
Br
-
is a better leaving group than
Cl
-
b.
CH
3
Br
H
H
CH
3
H
H Br
H
CH
3
H
CH
3
This compound is the only one that can undergo an E2 reaction because the
other compound does not have an axial hydrogen bonded to a
b
-carbon.
This compound will not be able to undergo an E2 reaction because it does not
have an adjacent H and Br that are both attached to axial bonds.