Chemistry Reference
In-Depth Information
O
Br
From
27
(R =
)
X=H
FVP
1050 ºC
5%
FVP, 1100 ºC
24%
O
X=F
i
-Pr
3
Si-CB
11
H
6
Cl
6
(Mes)
2
SiMe
2
PhCl, 110 ºC
79%
From
97
(R =
)
B
X
R
O
o
-C
6
H
4
Br
2
29
27
or
97
Pd
2
(dba)
3
,PCy
3
,DBU
DMF, 155 °C
40%
98
Scheme 28 Synthesis of indenocorannulene 98 [
48
,
124
-
126
]
values for [88·C
60
] and [(88)
2
·C
70
] are determined to be 0.80 and 0.79
,
Å
respectively.
C
60
C
70
=
[
88
·C
60
]
[(
88
)
2
·C
70
]
88
2.5
Indenocorannulene Family
2.5.1 Synthesis
The FVP synthesis of indenocorannulene (98) was conducted with phenyl-
corannulene (29)[
124
] or 2-bromobenzoylcorannulene (27)[
48
] (Scheme
28
).
The cyclization of 2-bromobenzoylcorannulene (27) is more efficient than that of
29. Compound 27 undergoes radical-type cyclization and subsequent decarbonyl-
ation to furnish 98. In solution-phase synthesis, indeno[1,2,3]annelation of PAHs
by a Suzuki-Heck-Type coupling cascade provided the extension of an aryl func-
tional group with a junction of a five-membered ring in a single synthetic step [
125
].
In contrast to the FVP synthesis of indenocorannulene (98) from phenyl-
corannulene, the fluoro-substituted analogue 29 (X
F) turns out to be very efficient
[
126
] (Scheme
28
). Catalytic cyclization is initiated by reaction of a silyl cation
with an aryl fluoride to generate a phenyl cation and, subsequently, Friedel-Crafts
reaction to an intramolecular aryl coupling, flowed by deprotonation, to give 98.
The enabling feature of this reaction is the exchange of carbon-fluorine for silicon-
fluorine bond enthalpies.
¼
