Photoarylation of Iodocarboranes with Unactivated (Hetero)Arenes: Facile Synthesis of 1,2-[(Hetero)Aryl]n-o-Carboranes (n=1,2) and o-Carborane-Fused Cyclics

Article abstract of DOI:10.1002/anie.201610810

Photoarylation of iodocarboranes with unactivated arenes/heteroarenes at room temperature has been achieved, for the first time, thus leading to the facile synthesis of a large variety of cage carbon mono(hetero)arylated and di(hetero)arylated o-carboranes. This work represents a clean, efficient, transition-metal-free, and cheap synthesis of functionalized carboranes, which has significant advantages over the known methods.

Full text of DOI:10.1002/anie.201610810

Angewandte
Communications
Chemie
International Edition: DOI: 10.1002/anie.201610810
German Edition: DOI: 10.1002/ange.201610810
Cage Compounds
Photoarylation of Iodocarboranes with Unactivated (Hetero)Arenes:
Facile Synthesis of 1,2-[(Hetero)Aryl]n-o-Carboranes (n = 1,2) and
o-Carborane-Fused Cyclics
Hangcheng Ni, Zaozao Qiu, and Zuowei Xie*
Abstract: Photoarylation of iodocarboranes with unactivated
arenes/heteroarenes at room temperature has been achieved,
for the first time, thus leading to the facile synthesis of a large
variety of cage carbon mono(hetero)arylated and di-
(hetero)arylated o-carboranes. This work represents a clean,
efficient, transition-metal-free, and cheap synthesis of func-
tionalized carboranes, which has significant advantages over
the known methods.
I
cosahedral carboranes are carbon-boron molecular clusters
which can be viewed as three-dimensional analogues to
benzene.[1] Their unique characteristics such as thermal and
chemical stabilities as well as three-dimensional structures
make them attractive building blocks for boron neuron
capture therapy agents in medicine,[2] functional units in
supramolecular design/materials,[3] and versatile ligands in
organometallic/coordination chemistry.[4] Recent results have
also demonstrated that cage carbon-arylated o-carboranes are
a class of AIE (aggregation induced emission) active and
stimuli-responsive luminescent materials, thus exhibiting very
interesting photophysical properties, where the carborane
moiety plays a unique role.[5] These arylated o-carboranes are
generally prepared from the condensation reaction of deca-
borane with the corresponding aryl or diaryl acetylenes,[6] and
the yields of the desired products are variable.[5,6] The
hypertoxicity of decaborane also complicates this method.
To tackle this problem, two cross-coupling reactions have
been developed using commercially available o-carborane as
a coupling partner (Scheme 1a). One is the Ullmann-type
coupling reaction of 1-copper-o-C2B10H11 or 1,2-dicopper-o-
C2B10H10 with aryl iodides to give 1-aryl-o-carboranes in
moderate yields.[7] No 1,2-diaryl-o-carboranes are produced,[8]
probably because of steric reasons and the homocoupling of
o-carboranyls.[9] Another one is the transition metal catalyzed
Kumada-type cross-coupling of 1-magnesium chloride-o-car-
boranes or 1-lithium-o-carboranes or 1,2-di-magnesium chlo-
ride-o-carboranes with aryl iodides for the preparation of 1,2-
Scheme 1. Cage carbon arylation of o-carboranes.
(aryl)n-o-carboranes (n = 1,2).[10] However, the strong basic
conditions used in the coupling reactions result in limited
substrate scope and poor functional-group tolerance. Thus, it
is important to develop new methodologies for cage carbon-
arylated o-carboranes.
In recent years, photocatalysis has been recognized as an
increasingly viable tool to realize one-electron transfer cross-
coupling reactions.[11] Among these, photoarylation of aryl
iodides with unactivated arenes is particularly attractive
because of its mild reaction conditions and broad substrate
scope.[12] Inspired by these results, we studied a UV light
promoted photoarylation of iodocarboranes with unactivated
(hetero)arenes at room temperature. The findings are
reported herein (Scheme 1b).
Direct irradiation of a benzene solution of 1-iodo-2-
methyl-o-caborane (1a) under 36 W UV lamp (l = 365 nm) at
room temperature for 24 hours gave the coupling product 1-
phenyl-2-methyl-o-caborane (3a) in 51% yield (GC; Table 1,
entry 1). Addition of 1.2 equivalents of Na2CO3 afforded 3a
in 92% yield (entry 2). The same yield was obtained with
40 equivalents of benzene in dichloromethane (DCM), while
the yield of 3a was decreased if 20 equivalents of benzene was
used (entries 3–6). Other solvents and bases did not improve
the yield of 3a (entries 8–14). Though an 18 W UV lamp
worked as well as a 36 W one, thus producing 3a in 92% yield
(entry 15), no reaction was observed without UV irradiation
(entry 18).
[*] H. Ni, Prof. Dr. Z. Xie
Department of Chemistry and State Key Laboratory of Synthetic
Chemistry, The Chinese University of Hong Kong
Shatin, N.T., Hong Kong (China)
E-mail: zxie@cuhk.edu.hk
Prof. Dr. Z. Qiu, Prof. Dr. Z. Xie
Shanghai-Hong Kong Joint Laboratory in Chemical Synthesis,
Shanghai Institute of Organic Chemistry, Chinese Academy of
Sciences, Shanghai (China)
Under the optimal reaction conditions (entry 15, Table 1),
the substrate scope was examined and the results are
compiled in Table 2. In general, the photoarylation reaction
proceeded well to give the desired products in very high yields
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.201610810.
Angew. Chem. Int. Ed. 2016, 55, 1 – 6
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
1
These are not the final page numbers!

Angewandte
Communications
Chemie
Table 1: Optimization of reaction conditions.[a]
Table 2: Synthesis of 1-(hetero)aryl-o-carboranes.[a,b]
Entry
Base
(equiv)
Benzene
(equiv)
Solvent
Yield
[%][b]
1
2
3
4
5
6
7
8
–
–
–
benzene
benzene
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
cyclohexane
THF
CH3CN
DMSO
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
51
92
82
86
92
92
81
25
55
91
16
8
81
24
92
55
58
n.r.
Na2CO3 (1.2)
Na2CO3 (1.2)
Na2CO3 (1.2)
Na2CO3 (1.2)
Na2CO3 (1.2)
Na2CO3 (0.6)
Et3N (1.2)
pyridine (1.2)
K2CO3 (1.2)
Na2CO3 (1.2)
Na2CO3 (1.2)
Na2CO3 (1.2)
Na2CO3 (1.2)
Na2CO3 (1.2)
Na2CO3 (1.2)
Na2CO3 (1.2)
Na2CO3 (1.2)
20
30
40
60
40
40
40
40
40
40
40
40
40
40
40
40
9
10
11
12
13
14
15[c]
16[d]
17[e]
18[f]
[a] Reaction conditions: 1a (0.2 mmol), solvent (2.0 mL), 36 W UV
(l=365 nm), room temperature for 24 h. [b] GC yield. [c] 18 W UV lamp
as the irradiation source. [d] 9 W UV lamp as the irradiation source.
[e] Reaction time was 12 h. [f] Without irradiation. DMSO=dimethyl-
sulfoxide, THF=tetrahydrofuran.
upon isolation. The nature of cage substitutents (R1) did not
affect the yields (3a–h). In contrast, the electron-rich arenes
worked much better than the electron-poor ones, and 1,4-
F2C6H4 only gave a trace amount of product (3k–m). For
unsymmetrical arenes, regioisomers were obtained. Anisole
gave the arylated product 3n in a total yield of 89% with
[a] All reactions were conducted on a 0.5 mmol scale of 1 in 5.0 mL of
DCM in a closed flask for 24 h at room temperature under the irradiation
of an 18 W UV lamp. [b] Yield of isolated product. [c] Irradiation for 48 h.
[d] Ratio determined by 1H NMR spectroscopy. [e] Reaction was carried
out in 5 mL of pyridine. [f] 1-Me-o-carborane was observed in 49% GC
yield.
a
ratio of o/m/p = 55:5:40. Naphthalene afforded two
regioisomers of 3o in 74% yield with a ratio of a/b = 88:12.
This method was compatible with a variety of heteroar-
enes. Furan, 2-methyl-furan, and pyrrole generated the
corresponding a-carboranylation products 3p, 3q, 3s, and
3u in very high yields (Table2). Thiophene and N-methyl
pyrrole gave both regioisomers in excellent yields with
a molar ratio of a/b = 89:11 for 3r or 86:14 for 3t,
respectively. In contrast, pyridine derivatives were not good
arylation agents. Pyridine led to the isolation of 3v in 49%
yield with a molar ratio of a/b = 47:53, whereas 2,6-lutidine
afforded a single isomer, 3w, in only 37% yield.
We noted that an unexpected intramolecular cyclization
product 4a was isolated in 22% yield in addition to 3d from
the reaction of 1-iodo-2-benzyl-o-carborane (1d) with ben-
zene (Table 2). This finding prompted us to study the
photomediated intramolecular cyclization for the synthesis
of o-carborane-fused cyclics. The results are outlined in
Table 3. Irradiation of 1d in DCM at room temperature for
48 hours generated 4a in 65% yield. It was found that the
reaction efficiency was dependent upon the substituents on
the phenyl ring. Electron-rich substituents offered the corre-
sponding cyclization product 4 in higher yields than those of
electron-poor ones (4a, 4b, 4c versus 4d, 4e). In contrast, the
efficiency of the construction of six-membered ring systems
was much higher than those of five-membered ones (4e
verrsus 4i; 4a versus 4g). In addition, o-carborane-fused
heterocyclics were also prepared in the same manner in very
high yields (4 f, 4j, and 4k). Following this motif, a seven-
membered ring (4l) was constructed in 21% yield.
Having achieved the intramolecular and intermolecular
photoarylation/photoheteroarylation of 1-iodo-o-carborane,
we then explored the photodi(hetero)arylation of 1,2-diiodo-
o-carborane (1s) with (hetero)arenes and the results are
summarized in Table 4. Under the standard reaction condi-
tions, irradiation of 1s with benzene in DCM at room
temperature for 48 hours gave 1,2-diphenyl-o-carborane (3t)
in 74% yield. Heteroarenes worked equally well, thus
affording the desired 1,2-diheteroarene-o-carboranes in 72–
80% yields. For furan, a single a,a-isomer, 5a, was produced,
2
www.angewandte.org
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2016, 55, 1 – 6
These are not the final page numbers!

Angewandte
Communications
Chemie
Table 3: Synthesis of o-carborane-fused (hetero)cyclics.[a,b]
4 f, 4j, and 4l were further confirmed by single-crystal X-ray
analyses.[13]
To gain some insight into the reaction mechanism, an
intermolecular primary kinetic isotope effect (KIE) experi-
ment was performed under the standard reaction conditions.
The low KIE value (kH/kD = 1.05) implied that an aromatic
À
C H bond cleavage is not involved in the rate-determining
step (Scheme 2a). In contrast, the addition of the radical
scavenger 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) led
to a significant decrease in the yield of 3a (from 86 to 24%;
Scheme 2b), thus suggesting that a radical process is involved
in the reaction.[14] In addition, control experiments indicated
that the arylation of 1a with benzene gave 3a in 51% yield in
the absence of any base, while such arylation did not proceed
without UV irradiation (Table 1, entries 1 and 18). These
experimental data suggest that both a base-promoted homo-
lytic aromatic substitution (BHAS) mechanism[15] and a pho-
toinduced carboranyl radical process involving the homolytic
[12g,16]
À
cleavage of the cage C I bond
may be operative in the
above photoarylation/photoheteroarylation reactions (see
Scheme S1 in the Supporting Information for details).
[a] All reactions were conducted on 0.5 mmol scale of 1 in 5.0 mL of
DCM in a closed flask for 48 h at room temperature under the irradiation
of an 18 W UV lamp. [b] Yield of isolated product. [c] cis-Alkene was used
as the starting material. [d] 1-Cinnamyl-o-carborane was isolated in 54%
yield.
Table 4: Synthesis of 1,2-di(hetero)aryl-o-carboranes.[a,b]
Scheme 2. Kinetic isotopic effect and radical trapping experiments.
In summary, a photoarylation/photoheteroarylation of
either 1-iodo-o-carborane or 1,2-diiodo-o-carborane with
a wide variety of arenes and heteroarenes under very mild
reaction conditions has been developed for the first time, and
is a very promising approach for clean, efficient, transition-
metal-free, and cheap synthesis of a large class of 1,2-
[(hetero)aryl]n-o-carboranes (n = 1,2). As this photoarylation
reaction does not require strong bases, photocatalysts, and
high temperatures, it is tolerant of many types of functional
groups. This work represents significant advances over the
known methods for the synthesis of cage C-arylated o-
carboranes,[6,7,10] and also sets a good example for the
functionalization of boron clusters using photochemistry
approach.
[a] All reactions were conducted on 0.5 mmol scale of 1s, 2.4 equiv of
Na2CO3 under the irradiation of an 36 W UV lamp in 5.0 mL of DCM in
a closed flask at room temperature for 48 h. [b] Yield of isolated product.
[c] Reaction for 72 h. [d] Ratio determined by 1H NMR spectroscopy.
while thiophene, pyrrole, and N-methylpyrrole generated
both a,a and a,b-isomers with the a,a-isomer as a major
product (5b–d). It was noted that such a diarylation reaction
was very sensitive to steric factors. For example, only the
monoarylation product was isolated from the reaction of 1s
with p-xylene, even after prolonged reaction time.
Experimental Section
Typical procedure for the preparation of 1-(hetero)aryl-o-carbor-
anes (3): Iodocarborane 1 (0.5 mmol), (hetero)arene (20 mmol), and
Na2CO3 (0.6 mmol) were mixed in dry CH2Cl2 (5 mL) in a 25 mL
Schlenk flask equipped with a magnetic stirring bar. Under an
atmosphere of dry nitrogen, the reaction mixture was irradiated using
an 18 W UV lamp (l = 365 nm) at room temperature for 24 h with
stirring. After removal of the solvent in vacuo, the residue was
1
The compounds 3–5 were fully characterized by H, 13C,
and 11B NMR spectroscopy, as well as high-resolution mass
spectrometry. The molecular structures of 3j, 3n, 3p, 3t, 3v,
Angew. Chem. Int. Ed. 2016, 55, 1 – 6
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
3
These are not the final page numbers!

Angewandte
Communications
Chemie
subjected to flash column chromatography on silica gel (230–
400 mesh) using n-hexane as the eluent to give the products 3.
Lugo, C. E. Moore, A. L. Rheingold, V. Lavallo, Inorg. Chem.
2015, 54, 2094 – 2096; f) L. M. A. Saleh, R. M. Dziedzic, S. I.
Khan, A. M. Spokoyny, Chem. Eur. J. 2016, 22, 8466 – 8470; g) F.
Teixidor, R. NfflÇez, C. ViÇas, R. Sillanpää, R. Kivekäs, Angew.
Chem. Int. Ed. 2000, 39, 4290 – 4292; Angew. Chem. 2000, 112,
4460 – 4462.
Acknowledgements
[5] a) K. Kenta, C. Yoshiki, J. Org. Chem. 2011, 76, 316 – 319; b) M.
Tominaga, H. Naito, Y. Morisaki, Y. Chujo, New J. Chem. 2014,
38, 5686 – 5690; c) K. R. Wee, W. S. Han, D. W. Cho, S. Kwon, C.
Pac, S. O. Kang, Angew. Chem. Int. Ed. 2012, 51, 2677 – 2680;
Angew. Chem. 2012, 124, 2731 – 2734; d) K. R. Wee, Y. J. Cho, S.
Jeong, S. Kwon, J. D. Lee, I. H. Suh, S. O. Kang, J. Am. Chem.
Soc. 2012, 134, 17982 – 17990; e) A. Ferrer-Ugalde, E. J. Juµrez-
PØrez, F. Teixidor, C. VaÇas, R. Sillanpää, E. PØrez-Inestrosa, R.
NfflÇez, Chem. Eur. J. 2012, 18, 544 – 553; f) K. R. Wee, Y. J. Cho,
J. K. Song, S. O. Kang, Angew. Chem. Int. Ed. 2013, 52, 9682 –
9685; Angew. Chem. 2013, 125, 9864 – 9867; g) C. Shi, H. Sun, X.
Tang, H. Lv, H. Yan, Q. Zhao, J. Wang, W. Huang, Angew. Chem.
Int. Ed. 2013, 52, 13434 – 13438; Angew. Chem. 2013, 125, 13676 –
13680; h) C. Shi, H. Sun, Q. Jiang, Q. Zhao, J. Wang, W. Huang,
H. Yan, Chem. Commun. 2013, 49, 4746 – 4748; i) H. J. Bae, J.
Chung, H. Kim, J. Park, K. M. Lee, T.-W. Koh, Y. S. Lee, S. Yoo,
Y. Do, M. H. Lee, Inorg. Chem. 2014, 53, 128 – 138; j) H. Naito,
Y. Morisaki, Y. Chujo, Angew. Chem. Int. Ed. 2015, 54, 5084 –
5087; Angew. Chem. 2015, 127, 5173 – 5176; k) A. Ferrer-Ugalde,
A. Gonzµlez-Campo, J. Rodríguez-Romero, R. Santillan, N.
Farfµn, R. Sillanpää, F. Teixidor, Chem. Eur. J. 2014, 20, 9940 –
9951; l) K. O. Kirlikovali, J. C. Axtell, A. Gonzalez, A. C. Phung,
S. I. Khan, A. M. Spokoyny, Chem. Sci. 2016, 7, 5132 – 5138.
[6] a) T. L. Heying, J. W. Ager, Jr., S. L. Clark, D. J. Mangold, H. L.
Goldstein, M. Hillman, R. J. Polak, J. W. Szymanski, Inorg.
Chem. 1963, 2, 1089 – 1092; b) U. Kusari, Y. Li, M. G. Bradley,
L. G. Sneddon, J. Am. Chem. Soc. 2004, 126, 8662 – 8663; c) Y.
Li, P. J. Carroll, L. G. Sneddon, Inorg. Chem. 2008, 47, 9193 –
9202; d) M. E. El-Zaria, K. Keskar, A. R. Genady, J. A. Ioppolo,
J. McNulty, J. F. Valliant, Angew. Chem. Int. Ed. 2014, 53, 5156 –
5160; Angew. Chem. 2014, 126, 5256 – 5260.
This work was supported by grants from the Research Grants
Council of the Hong Kong Special Administration Region
(Project No. 14304115 to Z.X.), Vice-Chancellorꢀs (CUHK)
Discretionary Fund, the National Natural Sciences Founda-
tion of China (No. 21372245 to Z.Q.), NSFC/RGC Joint
Research Scheme (N_CUHK442/14 to Z.X.), and CAS-
Croucher Funding Scheme.
Keywords: arenes · carboranes · cross-coupling ·
photochemistry · radicals
[1] For selected reviews, see: a) R. N. Grimes, Carboranes, 2nd ed.,
Elsevier, Oxford, 2011; b) N. S. Hosmane, Boron Science: New
Technologies and Applications, Taylor & Francis Books/CRC,
Boca Raton, FL, 2011; c) Z. Qiu, Tetrahedron Lett. 2015, 56,
963 – 971; d) D. Olid, R. NfflÇez, C. ViÇas, F. Teixidor, Chem. Soc.
Rev. 2013, 42, 3318 – 3336; e) M. Scholz, E. Hey-Hawkins, Chem.
Rev. 2011, 111, 7035 – 7062; f) J. Poater, M. Solà, C. ViÇas, F.
Teixidor, Angew. Chem. Int. Ed. 2014, 53, 12191 – 12195; Angew.
Chem. 2014, 126, 12387 – 12391.
[2] For selected reviews, see: a) M. F. Hawthorne, Angew. Chem.
Int. Ed. Engl. 1993, 32, 950 – 984; Angew. Chem. 1993, 105, 997 –
1033; b) A. F. Armstrong, J. F. Valliant, Dalton Trans. 2007,
4240 – 4251; c) F. Issa, M. Kassiou, L. M. Rendina, Chem. Rev.
2011, 111, 5701 – 5722.
[3] For selected examples, see: a) H. Jude, H. Disteldorf, S. Fischer,
T. Wedge, A. M. Hawkridge, A. M. Arif, M. F. Hawthorne, D. C.
Muddiman, P. J. Stang, J. Am. Chem. Soc. 2005, 127, 12131 –
12139; b) B. P. Dash, R. Satapathy, E. R. Gaillard, J. A. Maguire,
N. S. Hosmane, J. Am. Chem. Soc. 2010, 132, 6578 – 6587; c) M.
Koshino, T. Tanaka, N. Solin, K. Suenaga, H. Isobe, E.
Nakamura, Science 2007, 316, 853 – 853; d) D. Brusselle, P.
Bauduin, L. Girard, A. Zaulet, C. ViÇas, F. Teixidor, I. Ly, O.
Diat, Angew. Chem. Int. Ed. 2013, 52, 12114 – 12118; Angew.
Chem. 2013, 125, 12336 – 12340; e) J. Guo, D. Liu, J. Zhang, J.
Zhang, Q. Miao, Z. Xie, Chem. Commun. 2015, 51, 12004 –
12007; f) O. K. Farha, A. M. Spokoyny, K. L. Mulfort, M. F.
Hawthorne, C. A. Mirkin, J. T. Hupp, J. Am. Chem. Soc. 2007,
129, 12680 – 12681; g) J. J. Schwartz, A. M. Mendoza, N. Watta-
natorn, Y. Zhao, V. T. Nguyen, A. M. Spokoyny, C. A. Mirkin, T.
[7] R. Coult, M. A. Fox, W. R. Gill, P. L. Herbertson, K. Wade, J.
Organomet. Chem. 1993, 462, 19 – 29.
[8] Reaction of 1-phenyl-2-sodium-o-carborane with 4-nitrofluoro-
benzene gave the corresponding aromatic nucleophilic substitu-
tion product. The NO2 group is essential for this reaction, see:
a) K. Ohta, T. Goto, Y. Endo, Inorg. Chem. 2005, 44, 8569 – 8573;
b) K. Ohta, T. Goto, Y. Endo, Tetrahedron Lett. 2005, 46, 483 –
485.
[9] S. Ren, Z. Xie, Organometallics 2008, 27, 5167 – 5168.
[10] a) C. Tang, Z. Xie, Angew. Chem. Int. Ed. 2015, 54, 7662 – 7665;
Angew. Chem. 2015, 127, 7772 – 7775; b) J.-Y. Lu, H. Wan, J.
Zhang, Z. Wang, Y. Li, Y. Du, C. Li, Z.-T. Liu, Z.-W. Liu, J. Lu,
Chem. Eur. J. 2016, 22, 17542 – 17546.
[11] For selected reviews, see: a) A. Studer, D. P. Curran, Nat. Chem.
2014, 6, 765 – 773; b) T. L. Chan, Y. Wu, P. Y. Choy, F. Y. Kwong,
Chem. Eur. J. 2013, 19, 15802 – 15814; c) C.-L. Sun, Z.-J. Shi,
Chem. Rev. 2014, 114, 9219 – 9280; d) D. Ravelli, S. Protti, M.
Fagnoni, Chem. Rev. 2016, 116, 9850 – 9913; e) I. Ghosh, L.
Marzo, A. Das, R. Shaikh, B. Kçnig, Acc. Chem. Res. 2016, 49,
1566 – 1577; f) D. P. Hari, B. Kçnig, Angew. Chem. Int. Ed. 2013,
52, 4734 – 4743; Angew. Chem. 2013, 125, 4832 – 4842; g) C. K.
Prier, D. A. Rankic, D. W. C. MacMillan, Chem. Rev. 2013, 113,
5322 – 5363.
[12] a) D. Kalyani, K. B. McMurtrey, S. R. Neufeldt, M. S. Sanford, J.
Am. Chem. Soc. 2011, 133, 18566 – 18569; b) D. P. Hari, P.
Schroll, B. Kçnig, J. Am. Chem. Soc. 2012, 134, 2958 – 2961; c) P.
Zhang, C. C. Le, D. W. C. MacMillan, J. Am. Chem. Soc. 2016,
138, 8084 – 8087; d) D. Xue, Z.-H. Jia, C.-J. Zhao, Y.-Y. Zhang, C.
Wang, J. Xiao, Chem. Eur. J. 2014, 20, 2960 – 2965; e) D. Verga, F.
Doria, L. Pretali, M. Freccero, J. Org. Chem. 2010, 75, 3477 –
ˇ
Base, P. S. Weiss, J. Am. Chem. Soc. 2016, 138, 5957 – 5967;
h) S. G. McArthur, L. Geng, J. Guo, V. Lavallo, Inorg. Chem.
Front. 2015, 2, 1101 – 1104; i) D. J. Clingerman, W. Morris, J. E.
Mondloch, R. D. Kennedy, A. A. Sarjeant, C. Stern, J. T. Hupp,
O. K. Farha, C. A. Mirkin, Chem. Commun. 2015, 51, 6521 –
6523; j) F. Teixidor, R. Sillanpää, A. Pepiol, M. Lupu, C. ViÇas,
Chem. Eur. J. 2015, 21, 12778 – 12786; k) A. M. Cioran, A. D.
ˇ
´
Musteti, F. Teixidor, Z. Krpetic, I. A. Prior, Q. He, C. J. Kiely, M.
Brust, C. ViÇas, J. Am. Chem. Soc. 2012, 134, 212 – 221.
[4] a) N. S. Hosmane, J. A. Maguire in Comprehensive Organome-
tallic Chemistry III, Vol. 3 (Eds.: R. H. Crabtree, D. M. P.
Mingos), Elsevier, Oxford, 2007, chap. 5; b) Z. Xie, Coord.
Chem. Rev. 2002, 231, 23 – 46; c) Z. Xie, Acc. Chem. Res. 2003,
36, 1 – 9; d) A. M. Spokoyny, C. W. Machan, D. J. Clingerman,
M. S. Rosen, M. J. Wiester, R. D. Kennedy, C. L. Stern, A. A.
Sarjeant, C. A. Mirkin, Nat. Chem. 2011, 3, 590 – 596; e) C. A.
4
www.angewandte.org
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2016, 55, 1 – 6
These are not the final page numbers!

Angewandte
Communications
Chemie
3480; f) A. M. Linsenmeier, C. M. Williams, S. Bräse, J. Org.
[16] a) W. Wolf, N. Kharasch, J. Org. Chem. 1961, 26, 283 – 284;
Chem. 2011, 76, 9127 – 9130; g) Y. Cheng, X. Gu, P. Li, Org. Lett.
2013, 15, 2664 – 2667.
[13] See the Supporting Information for details.
[14] a) X. Zheng, L. Yang, W. Du, A. Ding, H. Guo, Chem. Asian J.
2014, 9, 439 – 442; b) Z. Xu, L. Gao, L. Wang, M. Gong, W.
Wang, R. Yuan, ACS Catal. 2015, 5, 45 – 50.
b) R. K. Sharma, N. Kharach, Angew. Chem. Int. Ed. Engl. 1968,
7, 36 – 44; Angew. Chem. 1968, 80, 69 – 77; c) T. Ho, C. Ku, S. H.
Liu, Tetrahedron Lett. 2001, 42, 715 – 717; d) J. M. OꢀConnell, E.
Moriarty, F. Aldabbagh, Synthesis 2012, 3371 – 3377; e) A. M.
Linsenmeier, C. M. Williams, S. Bräse, Eur. J. Org. Chem. 2013,
3847 – 3856.
[15] a) W. Liu, H. Cao, H. Zhang, H. Zhang, K. H. Chung, C. He, H.
Wang, F. Y. Kwong, A. Lei, J. Am. Chem. Soc. 2010, 132, 16737 –
16740; b) C.-L. Sun, H. Li, D.-G. Yu, M. Yu, X. Zhou, X.-Y. Lu,
K. Huang, S.-F. Zheng, B.-J. Li, Z.-J. Shi, Nat. Chem. 2010, 2,
1044 – 1049; c) E. Shirakawa, K.-I. Itoh, T. Higashino, T. Hay-
ashi, J. Am. Chem. Soc. 2010, 132, 15537 – 15539.
Manuscript received: November 5, 2016
Final Article published: && &&, &&&&
Angew. Chem. Int. Ed. 2016, 55, 1 – 6
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.angewandte.org
5
These are not the final page numbers!

Angewandte
Communications
Chemie
Communications
Cage Compounds
H. Ni, Z. Qiu, Z. Xie*
&&&& — &&&&
Photoarylation of Iodocarboranes with
Unactivated (Hetero)Arenes: Facile
Synthesis of 1,2-[(Hetero)Aryl]n-o-
Carboranes (n=1,2) and o-Carborane-
Fused Cyclics
Caught in a cage: Photoarylation of
iodocarboranes with unactivated arenes
and heteroarenes at room temperature
represents a facile approach to a large
variety of mono(hetero)arylated and di-
(hetero)arylated functionalized o-carbor-
anes. The procedure is clean, efficient,
transition-metal-free, and cheap.
6
www.angewandte.org
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Angew. Chem. Int. Ed. 2016, 55, 1 – 6
These are not the final page numbers!