Chemistry Reference
In-Depth Information
1.
Pd(PPh
3
)
4
, CuI, Et
3
N
H
TMS
OO
O
O
2.
H
TIPS
Cl
Pd(PPh
3
)
4
, CuI, Et
3
N
Cl
29
54%
TIPS
TMS
27
Cu(OAc)
2
, CuCl
pyridine
85%
R
R
TIPS
O
R
R
O
1.TBAF, THF
2.Cu(OAc)
2
, CuCl
pyridine
R
R
R
R
3.1N HCl, THF
4.TBSOTf, Et
3
N
O
R
R
O
R
TIPS
R
31
R = OTBS
15%
30
hv
benzene
100%
substituted [6
2
]CPPA
Fig. 16 Synthesis of CPPA precursor 31 and conversion to a CPPA derivative [
29
]
4 Cycloparaphenylenes
Recently, there has been an explosion of research and new syntheses surrounding
the cycloparaphenylenes (CPPs) [
32
,
35
-
58
]. These conjugated macrocycles are
comprised of sequential benzene rings bonded covalently at the
para
positions. As
such, they represent the smallest unit cycle of an armchair nanotube (Fig.
18
).
These “carbon nanohoops” have been envisioned as seeds for the growth of
extended nanotube structures as well as novel, porous, semiconducting, and fluo-
rescent materials in their own right [
36
,
53
,
56
,
57
].
