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178 Chapter 4
Copyright © 2017 Pearson Education, Inc.
87.
First convert the staggered Newman projection to an eclipsed Newman projection, which can then be
converted to a Fischer projection because that too is eclipsed (see page 188 of the text). Then name the
Fischer projection.
a.
Because one is
R
and the other is
S
, they are enantiomers
H
H
CH
3
CH
3
OH
H
CH
3
H
H
OH
H
H
3
C
CH
2
CH
3
CH
3
OH
H
R
H
CH
3
CH
3
CH
3
H
OH
H
H
H
H
H
3
C
CH
2
CH
3
OH
CH
3
OH
H
S
b.
Because one is
R,R
and the other is
S,S
, they are enantiomers.
CH
2
CH
3
H
Cl
CH
3
Br
H
CH
3
Br
H
H
Cl
H
Br
CH
3
Cl
H
CH
2
CH
3
CH
2
CH
3
CH
2
CH
3
CH
2
CH
3
CH
2
CH
3
CH
3
H
Br
H
Cl
H
R
R
CH
3
Cl
Br
H
CCH
3
H
S
S
Cl
H Br
88.
a.
The compound has four stereoisomers.
CH
2
OH
H OH
H OH
CH
2
OH
H OH
CH
2
OH
H OH
HO H
CH
2
OH
H OH
CH
2
OH
H OH
H OH
CH
2
OH
HO H
CH
2
OH
HO H
HO H
CH
2
OH
H OH
b.
The first two stereoisomers are optically inactive because they are meso compounds.
(Each has a plane of symmetry.)
89.
a.
CH
2
CH
2
Br
C
H Br
CH
2
CH
2
CH
3
R
b.
C C
Br
BrCH
2
OH
CH
H
H
R
R
O
c.
C C
H
H
3
C
CH
2
CH
3
Br
Br
H
R
S