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Chapter 4 181
Copyright © 2017 Pearson Education, Inc.
94.
a.
CH(CH
3
)
2
CH
3
CH
2
CH
CH
3
CH
2
CH
2
CH
2
CH
2
CH
3
CH
3
b.
CH
3
H
HOOC
OH
H
COOH
OH
CH
3
These represent the most stable
conformer of each enantiomer.
95.
In the transition state for amine inversion, the nitrogen atom is
sp
2
hybridized, which means that it has bond
angles of 120
°
. A nitrogen atom in a three-membered ring cannot achieve a 120
°
bond angle, so the amine
inversion that would interconvert the enantiomers cannot occur. Therefore, the enantiomers can be separated.
96.
The fact that the optical purity is 72
,
means that there is 72
,
enantiomeric excess of the
S
isomer and 28
,
racemic mixture. Therefore, the actual amount of the
S
isomer in the sample is 72
,
+
1
>
2
1
28
,
2
=
86
,
.
The amount of the
R
isomer in the sample is 1
>
2
1
28
,
2
=
14
,
1
or 100
,
-
86
,
=
14
,
2
.
97.
A
=
a diastereomer
C
=
a diastereomer
E
=
a diastereomer
B
=
a diastereomer
D
=
a diastereomer
98.
a.
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
b.
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
This is a pair of enantiomers
because they are
nonsuperimposable
mirror images.