Chemistry Reference
In-Depth Information
N
N
N
N
N
N
31
29
30
Fig. 8
Structures of 13,14-bis(2-pyridyl)pentaphenes [
36
]
Ar
Ar
1. 2
n
-BuLi
2
Ar
O
O
2.
HO
OH
t
-Bu
t
-Bu
33
t
-Bu
t
-Bu
32a
:Ar=Ph
32b
: Ar = 4-phenylphenyl
32c
: Ar = 3,5-dimethylphenyl
34a
,92%;
34b
,92%;
34c
,98%
Ar
Ar
KO
t
-Bu
Et
3
SiH
CF
3
CO
2
H
rt, 5 min
refluxing toluene
H
H
t
-Bu
t
-Bu
35a
, 93%;
35b
, 99%;
35c
,96%
Ar
Ar
H
H
A
C
Ar
Ar
B
t
-Bu
t
-Bu
t
-Bu
t
-Bu
37a
,44%;
37b
,46%;
37c
,40%
36
Scheme 6
Synthesis of diindeno-fused 4,5-diarylphenanthrenes [
37
]
the Schmittel cascade cyclization reactions [
38
-
40
] leading to
37a
. Similarly,
37b
and
37c
were obtained from benzannulated enediynes
32b
and
32c
, respectively.
The X-ray structure of
37a
(Fig.
9
) shows a severely twisted structure. As
expected, the two phenyl groups are bent away from each other but are in essen-
tially parallel orientation with a distance of ca. 2.9
˚
. They are also orientated at a
53.1
angle from the central phenanthrenyl system. A pronounced 46.1
twist
between the mean planes of rings A and C is much larger than that of
1
at 27.9
.
