Chemistry Reference
In-Depth Information
The stereogenic center is marked with an asterisk. The priority order of groups at this
center is
b
d
c
a
and the configuration is
S
. A word about the priority order may be helpful. The
C
C
C
2
3
group has three bonds from the attached carbon atom to the next atoms “out” and is
therefore of the highest priority. The remaining groups both begin with
−
CH
2
, so we
must proceed further. One group is
O
C
C
2
and the other is
C
2
C
C
H
Of these, the group with C=O has the higher priority because oxygen has a higher
atomic number than carbon.
The priority of the four groups is Br > Cl > F > H. The structure of the
R
enantiomer
is:
5.38
Cl
H
Br
F
5.39
a.
3
2
4
1
5
6
(
Z
,
Z
)-2,4-hexadiene or more precisely, (2Z,4
Z
)-2,4-hexadiene
If you have difficulty, draw the full structure:
H
3
H
C
H
C
C
2
4
H
3
C
C
5
H
3
C
H
At the double bond between C-2 and C-3, the priority order is CH
3
> H and
CH
3
CH=CH
−
> H. The two high-priority groups, CH
3
and CH
3
CH=CH
−
, are
Z
or
zusammen
. The same is true at the double bond between C-4 and C-5.
b.
(
E
,
E
)-2,4-hexadiene
