Chemistry Reference
In-Depth Information
O
X
O
12
13
14
-H
2
-H
2
2
-H
2
-H
2
15
Scheme 1 Formation of bowl-shaped hydrocarbons from 2 and 15
Another variation of the BAE structure are the cyclizations across the fjord
region, which are facilitated by the close proximity of the respective atoms.
Photocyclization as well as thermal cyclizations have been reported. Bifluore-
nylidene (2) and the PAE bi-4
H
-cyclopenta[
def
]phenanthren-4-ylidene (15)
[
68
,
69
], with their central five-membered rings, are fullerene fragments, and
potential starting materials for the preparation of bowl shaped hydrocarbons,
semifullerenes, and buckyballs (Scheme
1
)[
20
-
25
,
85
-
90
].
