Synthesis of Rationally Halogenated Buckybowls by Chemoselective Aromatic C?F Bond Activation

Article abstract of DOI:10.1002/anie.201700814

Halogenated buckybowls or bowl-shaped polycyclic aromatic hydrocarbons (BS-PAHs) are key building blocks for the “bottom-up” synthesis of various carbon-based nanomaterials with outstanding potential in different fields of technology. The current state of

Full text of DOI:10.1002/anie.201700814

Angewandte
Communications
Chemie
International Edition: DOI: 10.1002/anie.201700814
German Edition: DOI: 10.1002/ange.201700814
Bowl-Shaped Aromatic Systems
Synthesis of Rationally Halogenated Buckybowls by Chemoselective
À
Aromatic C F Bond Activation
Olena Papaianina, Vladimir A. Akhmetov, Alexey A. Goryunkov, Frank Hampel,
Frank W. Heinemann, and Konstantin Y. Amsharov*
Abstract: Halogenated buckybowls or bowl-shaped polycyclic
aromatic hydrocarbons (BS-PAHs) are key building blocks for
the “bottom-up” synthesis of various carbon-based nanoma-
terials with outstanding potential in different fields of technol-
ogy. The current state of the art provides quite a limited number
of synthetic pathways to BS-PAHs; moreover, none of these
approaches show high selectivity and tolerance of functional
groups. Herein we demonstrate an effective route to BS-PAHs
that includes directed intramolecular aryl–aryl coupling
through CÀF bond activation. The coupling conditions were
found to be completely tolerant toward aromatic CÀBr and
CÀCl bonds, thus allowing the facile synthesis of rationally
coupling of appropriate precursor molecules by means of
[
2,27]
flash vacuum pyrolysis (FVP),
surface-assisted cyclodehy-
[
28–31]
drogenation,
and palladium-catalyzed direct arylation
Unfortunately, none of these methods can be
[32–36]
methods.
applied to the synthesis of halogenated BS-PAHs. Although
the postsynthetic halogenation of corannulene, the smallest
[37,38]
buckybowl, has proven to be effective,
this approach is
not effective in the case of large and less symmetrical
molecules. Thus, the development of new methods that
enable the facile synthesis of halogenated BS-PAHs in
a fully controllable way is a matter of great interest and
importance.
[
39]
halogenated buckybowls with an unprecedented level of
selectivity. This finding opens the way to functionalized BS-
PAH systems that cannot be obtained by alternative methods.
Previously, Siegel and co-workers,
workers,
Ichikawa and co-
[
40–42]
[43,44]
and Amsharov and co-workers
demon-
strated the efficiency of the CÀF bond activation strategy for
the synthesis of PAH systems through intramolecular aryl–
aryl coupling. After thorough research, we discovered that
aluminum oxide mediated cyclodehydrofluorination is an
T
he amount of research in the field of bowl-shaped
polycyclic aromatic hydrocarbons (BS-PAHs) has been
expanding rapidly in recent years. The widespread interest
in BS-PAHs is induced by their unique properties originating
[
45]
effective method for the synthesis of BS-PAHs. Herein we
demonstrate that aryl–aryl coupling by g-aluminum oxide
mediated CÀF bond activation occurs under mild conditions
[1–3]
from the curved p system.
Because of the tremendous
strain inherent to the geodesic structure, the fabrication of
buckybowls frequently requires harsh reaction conditions that
do not tolerate functional groups. As a result, the controllable
functionalization of the buckybowl system still remains
a challenge, thus hampering further development in this
field. Appropriate functionalized buckybowls are important
with an unprecedented level of chemoselectivity. We also
found that the CÀF bond can be effectively activated in the
presence of more labile aromatic CÀBr and CÀCl bonds, thus
allowing the facile synthesis of halogenated BS-PAHs in
a fully controllable manner. The described technique is not
only straightforward and highly reproducible but opens access
to halogenated bowl-shaped systems which are not accessible
by other methods. Variously brominated indacenopicenes and
several halogenated diindenochrysenes were synthesized by
this approach with unprecedented levels of efficiency and
conversion.
[4–16]
starting materials for further derivatization
and key
building blocks for the rational synthesis of fullerenes,
nanotubes, and other related carbon-based nanostructures
[
17–26]
by a bottom-up strategy.
in particular brominated, bowls appear to be the most
important derivatives.
In this respect, halogenated, and
[
4–16]
The most often studied approaches
In the course of our studies on alumina-promoted
aromatic CÀF bond activation, we have found that the
to buckybowls are based on the intramolecular aryl–aryl
solvent plays a crucial role. Namely, it was found that the
solvent does not only help to distribute the precursor
homogeneously over alumina but fundamentally influences
the efficiency of the cyclodehydrofluorination. The promoting
effect of the solvent was investigated on the basis of the model
conversion of 1-fluoro-4-bromobenzo[c]phenanthrene (1)
into 3-bromobenzo[ghi]fluoranthene (2; Figure 1). To eval-
uate the solvent effect, we carried out the cyclodehydro-
fluorination for 30 min at the relatively low temperature of
[
*] O. Papaianina, Dr. F. Hampel, Dr. K. Y. Amsharov
Department of Organic Chemistry
Friedrich Alexander University Erlangen-Nuremberg
Henkestrasse 42, 91054 Erlangen (Germany)
E-mail: konstantin.amsharov@fau.de
Dr. F. W. Heinemann
Department of Inorganic Chemistry
Friedrich Alexander University Erlangen-Nuremberg
Egerlandstrasse 1, 91058 Erlangen (Germany)
1
1
208C. Under these conditions, only 0.5% conversion of
into 2 was observed when a solid-state strategy was applied
V. A. Akhmetov, Dr. A. A. Goryunkov
Department of Chemistry, Lomonosov Moscow State University
Leninskie Gory, 1–3, 119991 Moscow (Russia)
(no solvent).
The screening of various solvents revealed that o-di-
chlorobenzene (o-DCB) was superior in accelerating the
reaction. In the presence of o-DCB, the cyclodehydrofluori-
Supporting information and the ORCID identification number(s) for
the author(s) of this article can be found under:
http://dx.doi.org/10.1002/anie.201700814.
Angew. Chem. Int. Ed. 2017, 56, 1 – 6
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1
These are not the final page numbers!

Angewandte
Communications
Chemie
Scheme 1. Synthetic route to the brominated indacenopicenes. a) NBS,
DBPO, CCl , reflux 4 h, 85%; b) PPh , toluene, reflux 16 h, 98%;
4
3
c) ArCHO, tBuOK, EtOH, reflux 10 h, 80%; d) hn, I , propylene oxide,
2
cyclohexane (3a: 84%; 3b: 50%; 3c: 55%); e) g-Al O , o-DCB, micro-
2
3
wave irradiation (4a: 1508C, 30 min, 99%; 4b: 1508C, 1.5 h, 96%; 4c:
408C, 1.5 h 80%). DBPO=dibenzoyl peroxide, NBS=N-bromosucci-
2
nimide.
Figure 1. Top: Model transformation of 1 into 2, used for optimization
of the condensation conditions. Bottom: Diagram showing the effect
of the solvent on the conversion efficiency. All reactions were carried
out at 1208C for 30 min. A logarithmic scale has been used to show
the yields.
nation was found to be about 200 times faster than without
a solvent, thus resulting in the formation of 2 in more than
6
0% yield after 30 min. Chlorobenzene and bromobenzene
showed acceptable acceleration, yielding the target product in
4 and 5% yield, respectively. Almost no effect was observed
1
for fluorobenzene (0.8%) and nonpolar solvents, such as
benzene (0.5%) and mesytilene (0.3%). Polar aprotic sol-
vents, such as DMSO, DMF, and DMA, completely inhibited
the reaction because of the deactivation of active centers at
the alumina interface. When o-DCB was used as the solvent,
full conversion of 1 into 2 could be achieved by increasing
either the reaction time or the reaction temperature. Thus,
a reaction at 1508C was already complete after 30 min and
yielded pure 2 in nearly quantitative yield. HPLC analysis
revealed clean conversion into the target compound without
any sign of side-product formation. The condensation in
o-DCB could be conducted with the same efficiency either by
conventional heating in sealed glass ampoules or by micro-
wave-assisted heating. Although no remarkable microwave
effect was detected, all further experiments were carried out
in a microwave reactor.
The efficiency of the method was examined by the
synthesis of several halogenated bowl-shaped PAHs with an
indacenopicene or diindenochrysene core. The respective
precursor molecules were obtained by multistep organic
synthesis in accordance with the synthetic routes depicted in
Schemes 1 and 2. Because of the strain imposed by the bowl-
shaped indacenopicene structure, the corresponding cyclo-
dehydrofluorination proceeded more slowly than the model
reaction. Thus, when the solid-state strategy was applied, the
nonbrominated precursor 3a required about 60 h at 1508C to
be fully converted into the target 4a. The introduction of
Scheme 2. Synthetic route to the halogenated diindenochrysenes.
a) LiAlH , THF, 3 h; b) PCC, CH Cl , 08C, 4 h, 65%; c) ArCH PPh Br,
4
2
2
2
3
tBuOK, EtOH, reflux, 10 h, 70%; d) hn, I , propylene oxide, cyclohexane
2
(
6a: 50%; 6b: 42%; 6c: 47%); e) g-Al O , o-DCB, microwave irradi-
2 3
ation (7a: 2408C, 1 h, 95%; 7b: 2208C, 0.5 h, 98%; 7c: 2308C, 1 h,
63%). PCC=pyridinium chlorochromate.
additional bromine functionalities complicated the cycliza-
tion to a remarkable extent, probably because of mass-
transfer problems caused by a high melting point. All
attempts to generate the brominated indacenopicene 4b by
using the solid-state strategy showed a disappointedly low
conversion level even after 100 h at 1508C. An increase in the
temperature up to 200–2508C affected the selectivity without
a remarkable improvement in the yield. According to HPLC
analysis, in the high-temperature reactions, partial debromi-
nation and the formation of several unidentified side products
occurred.
In contrast, in the presence of o-DCB, the reaction
proceeded very smoothly and rapidly. Thus, 3b was converted
into the brominated product 4b in nearly quantitative yield in
just 1.5 h at 1508C. Interestingly, a further increase in the
temperature to 2508C did not affect the selectivity of the
process. In contrast to the solid-state strategy, no significant
debromination occurred, and no other side products were
detected. In the case of 3c, in which the bromine functionality
2
www.angewandte.org
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2017, 56, 1 – 6
These are not the final page numbers!

Angewandte
Communications
Chemie
is in close proximity to the cove region, the cyclodehydro-
precursor 7c occurred with the formation of several side
fluorination proceeds less readily because of steric hindrance
products. MS analysis revealed that the main side reaction
was a cross-coupling reaction of the target 7c.
around one CÀF bond. Thus, the cyclization of 3c at 1508C
gave monocyclized product as a major component. Accept-
able conversion of 3c into 4c was observed only at high
temperature (2408C for 1.5 h), although the monocyclized
intermediate was still present in the reaction mixture. Finally,
we examined the cyclization of the dibrominated precursor
These results indicate that at high temperatures (above
2008C), not only the CÀF bond in the cove regions, but also
the CÀF bond on the periphery undergoes partial activation,
thus leading to coupling products. Interestingly, such a trans-
formation has never been observed for the solid-state
approach. In other words, the high-temperature CÀF activa-
3
d, which was obtained by the direct bromination of
precursor 3a. In this case, the cyclodehydrofluorination
proceeded smoothly to yield the desired dibrominated bowl
tion of fluoroarenes by alumina in o-DCB also seems to be
suitable for intermolecular, transition-metal-free aryl–aryl
cross-coupling. A decreased in the condensation temperature
to 1808C completely prevented dimerization, but the con-
densation virtually stopped after the first ring closure to yield
the monocyclized product as the major component. The best
results were obtained by heating 6c at 2208C for 2 h. In this
case, the desired difluorinated bowl was obtained in pure
form by means of preparative HPLC in 63% yield.
4
d exclusively. The bromine positions after cyclization were
unambiguously confirmed by single-crystal X-ray analysis
Figure 2). The single crystals of 4d were obtained by the slow
(
evaporation of a solution in toluene.
Considerable difficulties were encountered with the
growing of crystals of diindenochrisenes. Regardless of the
method used, the chlorinated and fluorinated bowls 7b and 7c
formed long and extremely thin needles, which were not
suitable for X-ray crystallographic analysis. In the case of
dibrominated 7a, it was possible to grow thin needles that
showed only weak diffraction. Fortunately, after replacing the
bromine substituents with phenyl groups by a double Suzuki
coupling reaction with phenylboronic acid, the resulting
compound 8 crystallized as orange blocks, thus allowing us
to observe the bowl-shaped character of the diindenochry-
sene core experimentally for the first time (Figure 3).
Figure 2. Synthesis of dibrominated indacenopicene 4d by twofold
CÀF bond activation. The molecular structure of the target bowl 4d as
determined by X-ray diffraction analysis is shown in the inset. Thermal
ellipsoids are set at the 50% probability level.
Importantly, the desired BS-PAHs were formed as the
sole product and required no further purification procedure
(
except for 4c), which makes the method highly attractive for
preparative synthesis. The pure product can be obtained
typically in 95–98% yield by simple precipitation with
methanol directly from the reaction mixture. All indaceno-
picenes 4 were obtained as air-stable deep-orange crystalline
solids. Compounds showed moderate to low solubility in
typical PAH solvents, such as toluene, dichloromethane, and
chlorobenzene, and exhibited rich UV/Vis spectra with an
absorption tail in the visible region extending beyond 500 nm
Figure 3. Synthesis of bowl 8 and top and side views of the molecular
structure as determined by X-ray diffraction analysis. Thermal ellip-
soids are shown at the 50% probability level.
The molecular structures and electronic properties of the
two series of halogenated bowls with diindenochrysene and
indacenopicene carbon frameworks were considered at the
DFT level of the theory. It was found that halogenation had
no notable effect on the CÀC bond lengths and the bond
(
see the Supporting Information).
The strategy was also applied to the generation of novel,
more curved diindenochrysenes bearing Cl, Br, and F
functionalities. Because of the enhanced strain (in compar-
ison with indacenopicenes), the cyclodehydrofluorination in
this case required higher temperatures. Effective HF elimi-
nation was observed upon heating at 200–2408C after several
hours. Both dibrominated and dichlorinated bowls 7a and 7b
were obtained in high yield in pure form without any
additional purification steps by cyclization in o-DCB at
orders with respect to the pristine bowls (see the Supporting
Information). Notably, the diindenochrysene bowl is more
curved than indacenopicene (bowl depths are 1.78 and 1.62 ꢀ,
respectively), thus showing the larger steric strain of the
former molecule (Figure 4). This result is consistent with the
large relative formation energies of pristine and dibrominated
diindenochrysene 7a with respect to isomeric pristine and
2
408C for 1 h. In contrast, the cyclization of fluorinated
Angew. Chem. Int. Ed. 2017, 56, 1 – 6
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
3
These are not the final page numbers!

Angewandte
Communications
Chemie
optical E values indicate that both bowls can be regarded as
G
wide-band-gap semiconductors. As shown recently, pristine
indacenopicene is a soft one-electron acceptor and has
suitable HOMO and LUMO energy levels to function as
[46]
a p-acceptor material for organic electronic applications.
The small internal reorganization energy (l) for electron
i
transport and enhanced electron affinity of indacenopicene
and diindenochrysene cores make them suitable building
blocks for novel n-channel semiconductive materials in
organic thin-film transistors.
In summary, we have demonstrated a facile method for
the synthesis of halogenated bowl-shaped PAHs through
selective CÀF activation. The unprecedented high efficiency
of the approach has been demonstrated by the transformation
of appropriate precursors into the desired halogenated
buckybowls in nearly quantitative yield. Besides its simplicity
and scalability, the presented strategy enables the introduc-
tion of halogen functionalities at virtually any desired
position, which makes the approach superior to all alternative
methods for buckybowl synthesis. The obtained halogenated
diindenochrysenes and indacenopicenes are electron accept-
ors with frontier molecular orbitals delocalized over the
whole molecule and are characterized by band-gap values
typical for wide-band-gap semiconductors. The presence of
the peripheral halogen atoms makes possible further func-
tionalization and the fine tuning of physical–chemical proper-
ties. Thus, these compounds can be considered as highly
promising building blocks for novel acceptor materials with
electronic-type conductivity for organoelectronic applica-
tions, including solar cells, thin-film transistors, and blue-
light-emitting diodes.
Figure 4. Top: Frontier molecular orbital distributions in pristine
diindenochrysene and pristine indacenopicene (contour levels are
À3
given for value of 0.03 eꢀ ). Bottom: Side view of the DFT-optimized
structures showing the bowl-shaped geometries of the diindenochry-
sene and indacenopicene cores.
À1
dibrominated indacenopicene 4d (17 and 13 kJmol , respec-
tively). The HOMO and LUMO density distributions deter-
mined by DFT calculations for diindenochrysene and inda-
cenopicene are shown in Figure 4. The orbitals show the same
spatial structure associated with the pyracylene moiety
embedded in the buckybowls. The electronic structural data
obtained from DFT calculations and UV/Vis measurements
are summarized in Table 1.
Table 1: Electronic properties of pristine and halogenated diindeno-
chrysenes and indacenopicenes.
[
a]
opt
Compound
DFT data [eV]
ELUMO EG
EG
[
b]
EHOMO
li
EA
[eV]
Experimental Section
Indacenopicene derivatives
General procedure: g-Al O (neutral, 50–200 mm, 1 g) was
2
3
4
4
4
4
a
b
c
À5.30
À5.38
À5.43
À5.56
À3.20
À3.34
À3.33
À3.48
2.10
2.04
2.10
2.08
0.15
0.15
0.16
0.16
1.56
1.73
1.72
1.90
2.43
2.40
2.43
2.42
activated in a glass ampoule at 2508C in air for 10 min and then
activated at 5508C for 15 min in a vacuum (10 mbar). Activated
À3
aluminum oxide was added to a microwave vial containing the
fluoroarene (20 mg) dissolved in anhydrous o-dichlorobenzene
(3 mL). For a 100 mg scale, 3–5 g of alumina and 10–15 mL of
o-dichlorobenzene were used. The glass vial was closed with the cap
and placed in the microwave oven. All preparation steps were
performed under an argon atmosphere. Condensation was carried out
typically at 150–2408C for 0.5–3 h. After cooling to room temper-
ature, products were extracted with toluene. Pure products were
typically obtained in 95–98% yield by direct precipitation with
MeOH from the corresponding toluene extract.
d
Diindenochrysene derivatives
7
7
7
7
À5.32
À5.47
À5.47
À5.39
À3.16
À3.44
À3.43
À3.31
2.15
2.03
2.04
2.08
0.17
0.17
0.17
0.19
1.52
1.87
1.84
1.67
–
a
b
c
2.56
2.58
–
[a] PBE/TZ2P; values of the HOMO–LUMO gap (E ), the internal
G
reorganization energy of electron transfer (l), and the adiabatic electron
affinity (EA) are given. [b] Optical gap, EG =1240/lonset
i
opt
.
Acknowledgements
Notably, pristine diindenochrysene and indacenopicene
have virtually the same frontier molecular orbital levels and
are characterized by similar relatively high electron affinity
values. Halogenation of the bowls results in lowering of the
HOMO and LUMO levels by 0.1–0.3 eV, depending on the
number and nature of the halogen atoms, and the stepwise
growth of electron affinity by approximately 0.1–0.2 eV per
halogen atom. The optical HOMO–LUMO energy gaps were
estimated from the absorption-edge wavelength during UV/
Vis spectral analysis of the compounds dissolved in a mixture
of toluene and methanol. Our calculations and measured
K.Yu.A. and O.P. are grateful to the Deutsche Forschungsge-
meinschaft for financial support (AM 407). A.A.G. and
V.A.A. are grateful to the Russian Foundation for Basic
Research (grant no. 15-33-21083 mol_a_ved) for financial
support.
4
www.angewandte.org
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2017, 56, 1 – 6
These are not the final page numbers!

Angewandte
Communications
Chemie
[
[
[
23] X. Yu, J. Zhang, W. Choi, J. Y. Choi, J. M. Kim, L. Gan, Z. Liu,
Nano Lett. 2010, 10, 3343 – 3349.
24] E. H. Fort, P. M. Donovan, L. T. Scott, J. Am. Chem. Soc. 2009,
31, 16006 – 16007.
25] T. J. Hill, R. K. Hughes, L. T. Scott, Tetrahedron 2008, 64, 11360 –
1369.
[26] A. Mueller, K. Y. Amsharov, Eur. J. Org. Chem. 2015, 3053 –
056.
Conflict of interest
The authors declare no conflict of interest.
1
Keywords: aryl–aryl coupling · buckybowls · CÀF activation ·
1
halogenation · polycyclic aromatic hydrocarbons
3
[
[
27] V. M. Tsefrikas, L. T. Scott, Chem. Rev. 2006, 106, 4868 – 4884.
28] K. T. Rim, M. Siaj, S. Xiao, M. Myers, V. D. Carpentier, L. Liu, C.
Su, M. L. Steigerwald, M. S. Hybertsen, P. H. McBreen, G. W.
Flynn, C. Nuckolls, Angew. Chem. Int. Ed. 2007, 46, 7891 – 7895;
Angew. Chem. 2007, 119, 8037 – 8041.
[
[
1] Y. T. Wu, J. S. Siegel, Chem. Rev. 2006, 106, 4843 – 4867.
2] Fragments of Fullerenes and Carbon Nanotubes: Designed
Synthesis, Unusual Reactions, and Coordination Chemistry
[29] N. Abdurakhmanova, A. Mueller, S. Stepanow, S. Rauschen-
(
Eds.: M. A. Petrukhina, L. T. Scott), Wiley, Hoboken, 2012.
3] Y. T. Wu, T. C. Wu, M. K. Chen, H. J. Hsin, Pure Appl. Chem.
014, 86, 539 – 544.
bach, M. Jansen, K. Kern, K. Y. Amsharov, Carbon 2015, 84,
444 – 447.
[
[
2
[30] K. Amsharov, N. Abdurakhmanova, S. Stepanow, S. Rauschen-
bach, M. Jansen, K. Kern, Angew. Chem. Int. Ed. 2010, 49, 9392 –
9396; Angew. Chem. 2010, 122, 9582 – 9586.
4] A. K. Dutta, A. Linden, L. Zoppi, K. K. Baldridge, J. S. Siegel,
Angew. Chem. Int. Ed. 2015, 54, 10792 – 10796; Angew. Chem.
2
015, 127, 10942 – 10946.
[31] G. Otero, G. Biddau, C. Sꢂnchez-Sꢂnchez, R. Caillard, M. F.
Lꢃpez, C. Rogero, F. J. Palomares, N. Cabello, M. A. Basanta, J.
Ortega, J. Mꢄndez, A. M. Echavarren, R. Pꢄrez, B. Gꢃmez-Lor,
J. A. Martꢅn-Gago, Nature 2008, 454, 865 – 868.
[
[
[
[
[
5] K. Kawasumi, Q. Zhang, Y. Segawa, L. T. Scott, K. Itami, Nat.
Chem. 2013, 5, 739 – 744.
6] E. A. Jackson, B. D. Steinberg, M. Bancu, A. Wakamiya, L. T.
Scott, J. Am. Chem. Soc. 2007, 129, 484 – 485.
[
32] A. M. Echavarren, B. Gꢃmez-Lor, J. J. Gonzꢂlez, ꢆ. de Frutos,
7] T. Amaya, T. Nakata, T. Hirao, J. Am. Chem. Soc. 2009, 131,
Synlett 2003, 0585 – 0597.
[
33] D. Alberico, M. E. Scott, M. Lautens, Chem. Rev. 2007, 107, 174 –
1
0810 – 10811.
8] L. Meng, T. Fujikawa, M. Kuwayama, Y. Segawa, K. Itami, J.
Am. Chem. Soc. 2016, 138, 10351 – 10355.
9] L. T. Scott, E. A. Jackson, Q. Zhang, B. D. Steinberg, M. Bancu,
B. Li, J. Am. Chem. Soc. 2012, 134, 107 – 110.
238.
[34] S. Pascual, P. de Mendoza, A. M. Echavarren, Org. Biomol.
Chem. 2007, 5, 2727 – 2734.
[35] J. Liu, S. Osella, J. Ma, R. Berger, D. Beljonne, D. Schollmeyer,
X. Feng, K. Mꢇllen, J. Am. Chem. Soc. 2016, 138, 8364 – 8367.
[36] T. C. Wu, M. K. Chen, Y. W. Lee, M. Y. Kuo, Y. T. Wu, Angew.
Chem. Int. Ed. 2013, 52, 1289 – 1293; Angew. Chem. 2013, 125,
[
[
[
[
[
[
10] C. M. ꢁlvarez, H. Barbero, S. Ferrero, D. Miguel, J. Org. Chem.
016, 81, 6081 – 6086.
11] C. W. Lee, E. C. Liu, Y. T. Wu, J. Org. Chem. 2015, 80, 10446 –
0456.
12] E. C. Liu, M. K. Chen, J. Y. Li, Y. T. Wu, Chem. Eur. J. 2015, 21,
755 – 4761.
13] F. Furrer, A. Linden, M. C. Stuparu, Chem. Eur. J. 2013, 19,
3199 – 13206.
14] A. Sygula, R. Sygula, P. W. Rabideau, Org. Lett. 2005, 7, 4999 –
001.
2
1327 – 1331.
1
[37] T. J. Seiders, K. K. Baldridge, E. L. Elliott, G. H. Grube, J. S.
Siegel, J. Am. Chem. Soc. 1999, 121, 7439 – 7440.
[38] B. M. Schmidt, B. Topolinski, M. Yamada, S. Higashibayashi, M.
Shionoya, H. Sakurai, D. Lentz, Chem. Eur. J. 2013, 19, 13872 –
4
1
13880.
5
[39] O. Allemann, S. Duttwyler, P. Romanato, K. K. Baldridge, J. S.
Siegel, Science 2011, 332, 574 – 577.
15] R.-Q. Lu, Y.-N. Zhou, X.-Y. Yan, K. Shi, Y.-Q. Zheng, M. Luo,
X.-C. Wang, J. Pei, H. Xia, L. Zoppi, K. K. Baldridge, J. S. Siegel,
X.-Y. Cao, Chem. Commun. 2015, 51, 1681 – 1684.
[
40] K. Fuchibe, Y. Mayumi, N. Zhao, S. Watanabe, M. Yokota, J.
Ichikawa, Angew. Chem. Int. Ed. 2013, 52, 7825 – 7828; Angew.
Chem. 2013, 125, 7979 – 7982.
[
[
[
[
[
16] A. Sygula, G. Xu, Z. Marcinow, P. W. Rabideau, Tetrahedron
2
001, 57, 3637 – 3644.
[41] N. Suzuki, T. Fujita, J. Ichikawa, Org. Lett. 2015, 17, 4984 – 4987.
[42] N. Suzuki, T. Fujita, K. Yu. Amsharov, J. Ichikawa, Chem.
Commun. 2016, 52, 12948 – 12951.
17] A. Mueller, K. Y. Amsharov, M. Jansen, Fullerenes, Nanotubes,
Carbon Nanostruct. 2012, 20, 401 – 404.
18] A. Mueller, K. Y. Amsharov, M. Jansen, Tetrahedron Lett. 2010,
[43] K. Y. Amsharov, M. A. Kabdulov, M. Jansen, Chem. Eur. J. 2010,
16, 5868 – 5871.
5
1, 3221 – 3225.
19] A. Mueller, K. Y. Amsharov, Eur. J. Org. Chem. 2012, 6155 –
164.
[44] K. Y. Amsharov, P. Merz, J. Org. Chem. 2012, 77, 5445 – 5448.
[45] K. Y. Amsharov, M. A. Kabdulov, M. Jansen, Angew. Chem. Int.
Ed. 2012, 51, 4594 – 4597; Angew. Chem. 2012, 124, 4672 – 4675.
[46] S. N. Spisak, J. Li, A. Y. Rogachev, Z. Wei, O. Papaianina, K.
Amsharov, A. V. Rybalchenko, A. A. Goryunkov, M. A. Petru-
khina, Organometallics 2016, 35, 3105 – 3111.
6
20] B. Liu, J. Liu, H. B. Li, R. Bhola, E. A. Jackson, L. T. Scott, A.
Page, S. Irle, K. Morokuma, C. Zhou, Nano Lett. 2015, 15, 586 –
5
21] K. Y. Amsharov, Phys. Status Solidi B 2015, 252, 2466 – 2471.
22] J. R. Sanchez-Valencia, T. Dienel, O. Grçning, I. Shorubalko, A.
Mueller, M. Jansen, K. Amsharov, P. Ruffieux, R. Fasel, Nature
95.
[
[
Manuscript received: January 23, 2017
2014, 512, 61 – 64.
Final Article published: && &&, &&&&
Angew. Chem. Int. Ed. 2017, 56, 1 – 6
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
5
These are not the final page numbers!

Angewandte
Communications
Chemie
Communications
Bowl-Shaped Aromatic Systems
Efficiency that will bowl you over: The
activation of aromatic CÀF bonds in the
presence of more labile CÀBr and CÀCl
O. Papaianina, V. A. Akhmetov,
A. A. Goryunkov, F. Hampel,
F. W. Heinemann,
bonds enabled the fully controlled syn-
thesis of halogenated bowl-shaped poly-
cyclic aromatic hydrocarbons through
intramolecular aryl–aryl coupling (see
picture). Besides its simplicity and high
reproducibility, the technique provides
access to halogenated bowl-shaped sys-
tems that are not accessible by other
methods.
K. Y. Amsharov*
&&&& — &&&&
Synthesis of Rationally Halogenated
Buckybowls by Chemoselective Aromatic
CÀF Bond Activation
6
www.angewandte.org
ꢀ 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2017, 56, 1 – 6
These are not the final page numbers!