Chemistry Reference
In-Depth Information
Class IA
Class II
R
n
Shallower bowl
Lower
Deeper bowl
Higher
Class IB
G
inv
G
inv
Δ
Δ
X
Scheme 35 The correlations between structures and bowl-to-bowl inversion energy [
57
]
for some corannulene derivatives. They found the relationship can be empirically
expressed as in (
1
). This simple quartic equation provided a reasonable fit to the
experimental results [
57
]:
h
mol
i
4
G
inv
¼
ʔ
ð
bowl depth
=
0
:
87
Þ
11
:
5 kcal
=
ð
1
Þ
3 Sumanene
Sumanene (tricyclopenta[
def
,
jkl
,
pqr
]triphenylene, 2)saC
21
-hydrocarbon
containing three periphery methylene bridges, and it is also a basic bowl-shaped
fragment of buckminsterfullerene. Sumanene (2) is named after “suman”, the Hindi
and Sanskrit word for a type of flower [
133
]. In contrast to corannulene, the
chemistry of sumanene is relatively new because this compound was first success-
fully synthesized in the laboratory in 2003 [
134
].
3.1 Sumanene and Simple Sumanene Derivatives
3.1.1 Synthesis
In 1993, an attempt was made to synthesize sumanene (2) from tris(bromomethyl)-
triphenylene under FVP conditions [
133
,
135
]. Unfortunately, this protocol closed
up to two five-membered rings. Ten years later, Sakurai et al. provided a new
synthetic approach to prepare 2 in solution phase under mild conditions [
134
]. Sim-
ilar to Lawton's synthetic strategy for corannulene, they first constructed the three-
dimensional framework using tetrahedral sp
3
carbons and later aromatized the