Silver-catalyzed formal insertion of arynes into Rf-I bonds

Article abstract of DOI:10.1002/chem.201402846

An unprecedented silver-catalyzed formal insertion of arynes into R _f-I (R_f=CF₃, C₂F₅) bonds has been developed. This protocol provides easy access to various ortho-perfluoroalkyl iodoarenes under mild conditions. In this insertion reaction, an ionic atom-transfer reaction of R_fI occurs, and a silver-mediated metathesis process is involved in the efficient transfer of the electropositive iodine atom.

Full text of DOI:10.1002/chem.201402846

DOI: 10.1002/chem.201402846
Communication
&
Insertion Reactions
Silver-Catalyzed Formal Insertion of Arynes into RfÀI Bonds**
Yuwen Zeng and Jinbo Hu*[a]
Abstract: An unprecedented silver-catalyzed formal inser-
tion of arynes into RfÀI (Rf =CF3, C2F5) bonds has been de-
veloped. This protocol provides easy access to various
ortho-perfluoroalkyl iodoarenes under mild conditions. In
this insertion reaction, an ionic atom-transfer reaction of
RfI occurs, and a silver-mediated metathesis process is in-
volved in the efficient transfer of the electropositive
iodine atom.
Aromatic compounds bearing perfluoroalkyl (Rf) groups are
widely used in the fields of pharmaceuticals, agrochemicals,
and materials.[1] In particular, trifluoromethylated aromatics
play important roles in life-science-related applications because
the CF3 group can profoundly change both the biological and
physical properties of organic molecules.[2] As a result, many
methods have been developed for introducing CF3 group(s)
onto aromatic rings.[3] However, although significant progress
has been made in the trifluoromethylation of arenes,[4] to date,
little attention has been paid to the introduction of higher Rf
groups, such as pentafluoroethyl (C2F5) groups, into aromatic
compounds.[3f]
Scheme 1. Insertion of arynes into perfluoroalkyl iodides.
Arynes are highly reactive intermediates and have been
widely used in transition-metal-catalyzed coupling reactions.[5]
We have recently reported a silver-mediated trifluoromethyla-
tion–iodination of arynes to give the corresponding ortho-tri-
fluoromethyl iodoarenes (Scheme 1a).[6] Although the installa-
tion of CF3 and I groups was rather efficient, an excess amount
(3 equiv) of AgCF3 and 1-iodophenylacetylene was required to
achieve the optimal yields, with large quantities of silver phe-
nylacetylide being produced as a byproduct. Therefore, a cata-
lytic process for vicinal trifluoromethylation–iodination of
arynes by using substoichiometric amounts of silver species is
highly desirable. We reasoned that ortho-trifluoromethyl io-
doarenes and their long-chain Rf analogues could be synthe-
sized by a more atom-economic method, that is, silver-cata-
lyzed insertion of arynes into RfÀI bonds (Scheme 1a).
Perfluoroalkyl iodides (RfI) are known as readily available Rf
sources. These compounds could serve as both excellent RfÀ
and Rf precursors in many transformations.[7–9] For instance,
C
perfluoroalkyl iodides are known to undergo oxidative addi-
tions with transition metals, such as Pd,[3e,7a] Pt,[7a] Zn,[3b] Cu,[7b]
and Ni,[7c] to give high-valent perfluoroalkylmetal complexes in
cross-coupling reactions. However, in these cases, the electro-
positive iodine atoms were reduced to iodide anions, which
are hard to utilize in the subsequent conversions. In this
regard, atom transfer (AT) of RfI to organic molecules would be
an ideal process to achieve complete conversion of RfI
(Scheme 1b). Although the atom-transfer process has great
value in synthetic applications, it has previously been restricted
to radical additions.[8] To the best of our knowledge, the ionic
atom-transfer reaction of RfI has never been reported. We envi-
sioned that the insertion of in situ generated arynes into per-
fluoroalkylmetals (MRf) would give the corresponding arylmetal
intermediates, which would continue to undergo s-bond
metathesis[10,13] with RfI to give the desired products and re-
generate the MRf intermediates (Scheme 1c). Herein, we wish
to report an unprecedented protocol for a formal insertion[11]
of arynes into RfÀI bonds under silver(I) catalysis, representing
probably the first example of ionic atom-/group-transfer reac-
[a] Y. Zeng, Prof. Dr. J. Hu
Key Laboratory of Organofluorine Chemistry
Shanghai Institute of Organic Chemistry
Chinese Academy of Sciences
345 Ling-Ling Road, Shanghai, 200032 (P.R. China)
E-mail: jinbohu@sioc.ac.cn
[**] Rf =CF3, C2F5
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/chem.201402846.
Chem. Eur. J. 2014, 20, 1 – 6
1
ꢀ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Communication
tions of both perfluoroalkyl and iodine groups from RfI into
a single molecule (Scheme 1a–c).
effect of phen, making the aryl group (in ArAg) more electro-
negative and, thus, accelerating the iodine atom transfer step
(Scheme 1c).[16] Carrying out the reaction at room temperature
(RT) prevented the formation of PhCF3 (entry 11). Reducing the
concentration (0.1m) and quantity of CF3I (1.5 equiv) did not
have a significant effect on the yield of 2a (entry 12). This
result was surprising because in previous studies,[9a–c] large
excess (5–12 equiv) and high concentration (0.8–3.0m) of CF3I
solutions were needed to achieve favorable yields. Thus, in the
present case, gas-injection operations and specific devices,
such as Teflon-capped pressure tubes, were not required.[17] To
further simplify the experimental operation, the prepared
AgCF3 was exchanged for AgCF3 generated in situ (derived
from 1:1 molar ratio of AgNO3 and TMSCF3 in the presence of
CsF). Intriguingly, the efficiency of the reaction was not affect-
ed (entry 13). Further studies revealed that 5 mol% of phen-
AgNO3-TMSCF3 was sufficient for this insertion reaction
(entry 14). Thus, the optimal reaction conditions were found to
be as follows: 1.0 equivalent of 1a, 1.5 equivalents of CF3I
(0.1m), 2.0 equivalents of CsF, and 5 mol% of phen-AgNO3-
TMSCF3, in acetonitrile at RT.
To test the feasibility of our hypothesis, we carried out the
reaction of benzyne (generated in situ from 1a) with CF3I by
using various metal sources (10 mol%) as catalysts (Table 1).
Table 1. Optimization of the insertion of benzyne into CF3I.
Entry[a] Catalyst
Ligand CF3I [equiv]
Concentration [(m)]
T [8C] Yield [%][b]
PhCF3 2a
1
2
3
4
5
6
7
8
none
ZnCl2
FeBr2
none 2 (0.4)
none 2 (0.4)
none 2 (0.4)
none 2 (0.4)
none 2 (0.4)
none 2 (0.4)
none 2 (0.4)
none 2 (0.4)
50
50
50
50
50
50
50
50
50
50
RT
RT
RT
RT
0
0
0
0
0
2
8
11
10
5
0
0
0
0
0
Pd(OAc)2
Ni(acac)2
CuI
AgNO3
AgCF3
AgCF3
AgCF3
AgCF3
AgCF3
0
23
52
43
84
88
89
86
88
9
TMP
2 (0.4)
To explore the scope of the present reaction, we next exam-
ined the insertion of various substituted arynes into trifluoro-
methyl iodide (Scheme 2). In some cases, modifications, such
as reducing the reaction temperature and increasing the cata-
lyst loading, were needed to achieve the optimal yields. Mod-
erate to good yields were obtained for both symmetrical (2a–
2 f) and unsymmetrical aryne precursors (2g–2l). Functional
10
11
12
13
14[c]
phen 2 (0.4)
phen 2 (0.4)
phen 1.5 (0.1)
0
0
0
0
AgNO3 +TMSCF3 phen 1.5 (0.1)
AgNO3 +TMSCF3 phen 1.5 (0.1)
[a] General conditions: 1a (0.4 mmol, 1 equiv), CsF (0.8 mmol, 2 equiv),
catalyst (10 mol%) in MeCN for 12 h. AgCF3 was preprepared before use.
acac=acetylacetonate, TMP=2,2,6,6-tetramethyl-piperidine, phen=1,10-
phenanthroline. [b] Determined by 19F NMR spectroscopy. [c] The catalyst
loading was reduced to 5 mol%.
Firstly, we found that no insertion reaction occurred in the ab-
sence of a metal catalyst (entry 1). We also tested the reaction
in the presence of transition-metal salts, such as ZnCl2, FeBr2,
Pd(OAc)2, Ni(acac)2, and CuI; however, no desired product was
detected (entries 2–6). Gratifyingly, when AgNO3 was em-
ployed, insertion product 2a and the undesired protonated
product PhCF3 were formed in 23 and 8% yield, respectively
(entry 7). Replacing AgNO3 with trifluoromethylsilver (AgCF3)[12]
gave 2a in 52% yield, along with 11% yield of PhCF3 (entry 8).
This finding was in line with our previous study,[6] in which we
discovered that silver(I) species are an appropriate transition
metal for the transfer of electropositive iodine atoms. The ad-
vantage of silver species comes not only from the moderate
nucleophilic reactivity of ArAg species towards RfI,[13] but also
from the orthogonal reactivity between RfAg and ArI.[6,12d,e] It
should be noted that although silver(I) species are widely used
as soft Lewis acids and as mild oxidants, their application in
catalytic CÀX coupling is rare.[14] To further enhance the effi-
ciency of this insertion reaction, a range of ligands were
screened. Although the previously reported hindered mono-
dentate ligand 2,2,6,6-tetramethylpiperidine (TMP) proved to
be ineffective (entry 9), 1,10-phenanthroline (phen) gave
a much higher yield (entry 10).[15] This dramatic improvement
could be attributed to the high donor ability and strong trans
Scheme 2. Scope of silver-catalyzed insertion of arynes into CF3I.[a]
[a] The reaction was conducted on a 2 mmol scale under the optimized con-
ditions. Yields are of isolated products. [b] 0.2 equivalents phen-AgCF3.
[c] Isolated as a mixture, the ratio of regioisomers was determined by
19F NMR spectroscopy prior to isolation. [d] At 08C. [e] 0.1 equivalents phen-
AgCF3. [f] Contains ꢀ5% impurity.
&
&
Chem. Eur. J. 2014, 20, 1 – 6
www.chemeurj.org
2
ꢀ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

Communication
groups, such as acetal, ether, and allyl groups, were compatible
with this reaction (2e, 2h, and 2j). However, the sterically hin-
dered substrate, 3,6-dimethylbenzyne, gave the product 2d in
relatively lower yield. Remarkably, 4,5-indolyne[18] underwent
CF3ÀI bond insertion to form 2l in 76% yield. The indole ring
is one of the “privileged structures” in natural products and
medicinal agents.[19] It should be noted that despite the great
variety of strategies developed to synthesize C2- and C3-func-
tionalized indoles, methods to synthesize benzenoid-substitut-
ed indoles remain limited.[20]
Scheme 4. Regioselectivity of 3-substituted arynes.
The scope of silver-catalyzed insertion of arynes into other
RfÀI bonds was also studied. To our surprise, although C2F5I un-
derwent this insertion reaction smoothly, other RfI compounds,
such as (CF3)2CFI and C4F9I, failed to give any desired products.
When the similar conditions (as those mentioned in Scheme 2)
conditions were used for C2F5ÀI bond insertion, similar results
were obtained (Scheme 3). It is worth noting that the regiose-
steric effect of the ligands may be arranged as follows:
CF2CF3 >CF3 (Scheme 2 and 3, 2j versus 3j); CF3 >phen
(Scheme 2, 2j); phen>TMP (2j versus the single isomer that
was previously reported[6]). In addition, an ortho donating
group on the aryne could serve as a directing group and en-
hance the regioselectivity of the products. Hence, the reaction
of 3-methoxylbenzyne gave only 2h or 3h without other iso-
mers.
To gain more insights into the different reactivity of perflu-
oroalkyl iodides, we examined the stability of AgCF(CF3)2 and
AgC4F9, which were prepared from AgF and the corresponding
TMSRf derivatives, in a 1:1 ratio, at room temperature in aceto-
nitrile. Naumann et al. reported the preparation and characteri-
zation of AgRf species by means of ligand-exchange reactions
of AgNO3 and Cd(Rf)2 in aprotic polar solvents [Eq. (1)].[21] We
found that AgCF(CF3)2 was stable in MeCN and existed as an
equilibrium between the neutral species AgCF(CF3)2·D (D=sol-
vent) and the ate complex [Ag(CF(CF3)2)2]À. However, when
1,10-phenanthroline was added into this solution, brown sedi-
ment was instantly formed and the original fluorine signals dis-
appeared from the 19F NMR spectrum [Eq. (2)]. In contrast, the
reaction of TMSC4F9 and AgF gave an unidentified product,
which may be generated from the decomposition of the
AgC4F9 intermediate [Eq. (3)]. Thus, the failure of RfÀI bond in-
sertion reaction (when Rf =CF(CF3)2, C4F9) may be explained by
the low stability of AgRf, although the origin of this low stabili-
ty remains unknown.[22]
Scheme 3. Scope of silver-catalyzed insertion of arynes into C2F5I.[a]
[a] The reaction was conducted on a 1 mmol scale under the optimized con-
ditions. Yields are of isolated products. [b] 0.2 equivalents phen-AgC2F5.
[c] Isolated as a mixture, the ratio of regioisomers was determined by
19F NMR spectroscopy prior to isolation. [d] At 08C. [e] 0.1 equivalents phen-
AgC2F5.
lectivity in 2j and 3j was 4.09:1 and 7.33:1, respectively. In
contrast, the previously reported trifluoromethylation–iodina-
tion of 3-allylbenzyne gave only one isomer.[6] This difference
in regioselectivity can be explained by the repulsion of the
ortho-substituent group of the aryne by the ligand in the coor-
dinated AgCF3 species (Scheme 4). This result is consistent with
an increase in steric hindrance and rigidity of phen-AgCF3 to-
wards 3-substituted arynes compared with that of the previ-
ously reported TMP-AgCF3 intermediate (Scheme 4a). Thus, the
To probe whether radical intermediates are involved in this
insertion reaction, 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO;
2.0 equiv), an efficient free radical scavenger, was introduced
as an additive under the standard conditions [Eq. (4a)]. An
identical yield (89%) of 2a was obtained, suggesting that
TEMPO has no significant effect on the reaction efficiency. We
also examined the reaction in the presence of an electron-
Chem. Eur. J. 2014, 20, 1 – 6
www.chemeurj.org
3
ꢀ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Communication
Liu, Chem. Commun. 2011, 47, 4300; l) T. Liu, Q. Shen, Org. Lett. 2011,
13, 2342; m) C.-P. Zhang, J. Cai, C.-B. Zhou, X.-P. Wang, X. Zheng, Y.-C.
Gu, J.-C. Xiao, Chem. Commun. 2011, 47, 9516; n) N. D. Litvinas, P. S. Fier,
J. F. Hartwig, Angew. Chem. 2012, 124, 551; Angew. Chem. Int. Ed. 2012,
51, 536; o) L. Chu, F.-L. Qing, J. Am. Chem. Soc. 2012, 134, 1298; p) J.-J.
Dai, C. Fang, B. Xiao, J. Yi, J. Xu, Z.-J. Liu, X. Lu, L. Liu, Y. Fu, J. Am. Chem.
Soc. 2013, 135, 8436; q) X. Wang, Y. Xu, F. Mo, G. Ji, D. Qiu, J. Feng, Y.
Ye, S. Zhang, Y. Zhang, J. Wang, J. Am. Chem. Soc. 2013, 135, 10330;
r) K.-P. Wang, S. Y. Yun, P. Mamidipalli, D. Lee, Chem. Sci. 2013, 4, 3205;
s) S. Seo, J. B. Taylor, M. F. Greaney, Chem. Commun. 2013, 49, 6385. For
reviews, see:t) D. J. Burton, Z. Y. Yang, Tetrahedron 1992, 48, 189;
u) O. A. Tomashenko, V. V. Grushin, Chem. Rev. 2011, 111, 4475; v) S. Roy,
B. T. Gregg, G. W. Gribble, V.-D. Le, S. Roy, Tetrahedron 2011, 67, 2161.
[5] For recent examples on benzyne chemistry, see: a) J. L. Henderson, A. S.
Edwards, M. F. Greaney, J. Am. Chem. Soc. 2006, 128, 7426; b) Z. Liu,
R. C. Larock, Angew. Chem. 2007, 119, 2587; Angew. Chem. Int. Ed. 2007,
46, 2535; c) C. D. Gilmore, K. M. Allan, B. M. Stoltz, J. Am. Chem. Soc.
2008, 130, 1558; d) F. Sha, X. Huang, Angew. Chem. 2009, 121, 3510;
Angew. Chem. Int. Ed. 2009, 48, 3458; e) A. T. Biju, F. Glorius, Angew.
Chem. 2010, 122, 9955; Angew. Chem. Int. Ed. 2010, 49, 9761; f) T.
Hamura, Y. Chuda, Y. Nakatsuji, K. Suzuki, Angew. Chem. 2012, 124,
3424; Angew. Chem. Int. Ed. 2012, 51, 3368; g) S. Y. Yun, K.-P. Wang, N.-K.
Lee, P. Mamidipalli, D. Lee, J. Am. Chem. Soc. 2013, 135, 4668; h) H.
Yoshida, R. Yoshida, K. Takaki, Angew. Chem. 2013, 125, 8791; Angew.
Chem. Int. Ed. 2013, 52, 8629.
transfer (ET) scavenger. When 2.0 equivalents of para-dinitro-
benzene (DNB) was employed as a SET inhibitor, desired prod-
uct 2a was formed in 87% yield [Eq. (4b)]. Thus, these obser-
vations indicate that a mechanism involving radical or SET
pathways is not likely.[23]
In conclusion, we have developed a silver-catalyzed insertion
of arynes into RfÀI bonds under mild conditions. In this reac-
tion, RfI compounds were transferred to aryne intermediates
through an ionic atom-/group-transfer process. This protocol
provides not only a quick access to the corresponding ortho-
perfluoroalkyl iodoarenes, but also a fundamentally new and
intriguing pathway for RfI atom transfer. Further exploration of
this new type of insertion reaction and the reactivity of RfI is in
progress.
[6] Y. Zeng, L. Zhang, Y. Zhao, C. Ni, J. Zhao, J. Hu, J. Am. Chem. Soc. 2013,
135, 2955.
[7] a) D. T. Rosevear, F. G. A. Stone, J. Chem. Soc. A 1968, 164; b) V. C. R.
McLoughlin, J. Thrower, Tetrahedron 1969, 25, 5921; c) D. W. McBride,
S. L. Stafford, F. G. A. Stone, J. Chem. Soc. 1963, 723.
[8] For atom transfer/radical addition of RfI to alkenes, see: a) R. N. Haszel-
dine, J. Chem. Soc. 1949, 2856; b) T. Fuchikami, I. Ojima, Tetrahedron
Lett. 1984, 25, 303; c) C. Amato, C. Naud, P. Calas, A. Commeyras, J. Fluo-
rine Chem. 2002, 113, 55.
[9] For SET of RfI to give Rf radical, see: Ref. [3e] and a) D. A. Nagib, M. E.
Scott, D. W. C. MacMillan, J. Am. Chem. Soc. 2009, 131, 10875; b) A. T.
Herrmann, L. L. Smith, A. Zakarian, J. Am. Chem. Soc. 2012, 134, 6976;
c) Y. Ye, M. S. Sanford, J. Am. Chem. Soc. 2012, 134, 9034.
Acknowledgements
Support of our work by the National Basic Research Program
of China (2012CB821600, 2012CB215500), the National Natural
Science Foundation of China (21372246, 20825209), Shanghai
QMX program (13QH1402400), and the Chinese Academy of
Sciences is gratefully acknowledged.
[10] R. Waterman, Organometallics 2013, 32, 7249.
[11] Here we use the word “formal” because the Rf and I groups in the prod-
uct were not from the same RfI molecule.
Keywords: arynes · insertions · iodination · perfluoroalkyl
iodide · perfluoroalkylation
[12] For preparation and reactivity of AgCF3, see: a) W. E. Tyrra, J. Fluorine
Chem. 2001, 112, 149; b) W. Tyrra, Heteroat. Chem. 2002, 13, 561; c) H. K.
Nair, J. A. Morrison, J. Organomet. Chem. 1989, 376, 149; d) Y. Ye, S. H.
Lee, M. S. Sanford, Org. Lett. 2011, 13, 5464; e) A. Hafner, S. Brꢂse,
Angew. Chem. 2012, 124, 3773; Angew. Chem. Int. Ed. 2012, 51, 3713.
[13] A similar electrophilic reactivity of RfI has been found in Cu chemistry,
see ref. [3d].
[14] For selected examples of silver-catalyzed CÀX coupling, see: a) H. Hof-
meister, K. Annen, H. Laurent, R. Wiechert, Angew. Chem. 1984, 96, 720;
Angew. Chem. Int. Ed. Engl. 1984, 23, 727; b) P. Tang, T. Furuya, T. Ritter,
J. Am. Chem. Soc. 2010, 132, 12150; c) T. Xu, X. Mu, H. Peng, G. Liu,
Angew. Chem. 2011, 123, 8326; Angew. Chem. Int. Ed. 2011, 50, 8176;
d) Z. Wang, L. Zhu, F. Yin, Z. Su, Z. Li, C. Li, J. Am. Chem. Soc. 2012, 134,
4258; e) F. Yin, Z. Wang, Z. Li, C. Li, J. Am. Chem. Soc. 2012, 134, 10401.
[15] Similar results were observed when other bidentate ligands, such as
2,2’-bipyride, 1,2-ethanediamine, and proline, were used instead of
phen. For more details, see the Supporting Information.
[16] RfI species are found to be milder I+ reagents compared with 1-iodo-
phenylacetylene, thus, a strong ligand is needed to enhance the nucle-
ophilicity of the aryl group.
[17] CF3I was predissolved in MeCN and stored in a refrigerator with the ex-
clusion of light. This solution is stable and could be readily in situ, dilut-
ed to a desired concentration before use.
[18] For the synthesis and reactivity of indolyne, see: a) G.-Y. Im, S. M. Bron-
ner, A. E. Goetz, R. S. Paton, P. H.-Y. Cheong, K. N. Houk, N. K. Garg, J.
Am. Chem. Soc. 2010, 132, 17933; b) S. M. Bronner, A. E. Goetz, N. K.
Garg, J. Am. Chem. Soc. 2011, 133, 3832.
[19] F. R. de Sꢃ Alves, E. J. Barreiro, C. A. M. Fraga, Mini-Rev. Med. Chem. 2009,
9, 782.
[1] a) P. Kirsch, Modern Fluoroorganic Chemistry, Wiley-VCH, Weinheim,
2004; b) K. Uneyama, Organofluorine Chemistry, Blackwell, Oxford, 2006.
[2] a) J. P. Bꢁguꢁ, D. Bonnet-Delpon, Bioorganic and Medicinal Chemistry of
Fluorine, Wiley-VCH, Weinheim, 2008; b) I. Ojima, Fluorine in Medicinal
Chemistry and Chemical Biology, Wiley-Blackwell, Chichester, 2009.
[3] For perfluoroalkylation of arenes, see: a) G. V. D. Tiers, J. Am. Chem. Soc.
1960, 82, 5513; b) T. Kitazume, N. Ishikawa, Chem. Lett. 1982, 137;
c) R. N. Loy, M. S. Sanford, Org. Lett. 2011, 13, 2548; d) Q. Qi, Q. Shen, L.
Lu, J. Am. Chem. Soc. 2012, 134, 6548; e) A. Hafner, A. Bihlmeier, M.
Nieger, W. Klopper, S. Brꢂse, J. Org. Chem. 2013, 78, 7938; f) A. Lishchyn-
skyi, V. V. Grushin, J. Am. Chem. Soc. 2013, 135, 12584.
[4] For recent examples of aromatic trifluoromethylation, see: a) M. Oishi,
H. Kondo, H. Amii, Chem. Commun. 2009, 1909; b) R. Koller, K. Stanek,
D. Stolz, R. Aardoom, K. Niedermann, A. Togni, Angew. Chem. 2009, 121,
4396; Angew. Chem. Int. Ed. 2009, 48, 4332; c) E. J. Cho, T. D. Senecal, T.
Kinzel, Y. Zhang, D. A. Watson, S. L. Buchwald, Science 2010, 328, 1679;
d) L.-L. Chu, F.-L. Qing, Org. Lett. 2010, 12, 5060; e) N. D. Ball, J. W.
Kampf, M. S. Sanford, J. Am. Chem. Soc. 2010, 132, 2878; f) X. Wang, L.
Truesdale, J.-Q. Yu, J. Am. Chem. Soc. 2010, 132, 3648; g) C. P. Zhang,
Z. L. Wang, Q. Y. Chen, C. T. Zhang, Y. C. Gu, J. C. Xiao, Angew. Chem.
2011, 123, 1936; Angew. Chem. Int. Ed. 2011, 50, 1896; h) H. Morimoto,
T. Tsubogo, N. D. Litvinas, J. F. Hartwig, Angew. Chem. 2011, 123, 3877;
Angew. Chem. Int. Ed. 2011, 50, 3793; i) Y. Ji, T. Brueckl, R. D. Baxter, Y. Fu-
jiwara, L. B. Seiple, S. Su, D. G. Blackmond, P. S. Baran, Proc. Natl. Acad.
Sci. USA 2011, 108, 14411; j) D. A. Nagib, D. W. C. Macmillan, Nature
2011, 480, 224; k) J. Xu, D.-F. Luo, B. Xiao, Z.-J. Liu, T.-J. Gong, Y. Fu, L.
&
&
Chem. Eur. J. 2014, 20, 1 – 6
www.chemeurj.org
4
ꢀ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!

Communication
[20] a) R. J. Sundberg, Indoles (Best synthetic Methods), Academic Press, New
York, 1996; b) M. Bandini, A. Eichholzer, Angew. Chem. 2009, 121, 9786;
Angew. Chem. Int. Ed. 2009, 48, 9608.
[23] For our reasoning on the unlikely pathway for the formation of 2 and 3
by means of oxidative addition and reductive elimination, see the Sup-
porting Information.
[21] For NMR studies of AgRf, see: D. Naumann, W. Wessel, J. Hahn, W. Tyrra,
J. Organomet. Chem. 1997, 547, 79.
[22] Recently, Grushin reported a similar stability of higher CuRf species, see
Ref. [3 f].
Received: March 31, 2014
Published online on && &&, 0000
Chem. Eur. J. 2014, 20, 1 – 6
www.chemeurj.org
5
ꢀ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
&
&
These are not the final page numbers! ÞÞ

Communication
COMMUNICATION
&
Insertion Reactions
Y. Zeng, J. Hu*
&& – &&
Silver-Catalyzed Formal Insertion of
Arynes into RfÀI Bonds
Silver catalysis: Silver nitrate (AgNO3)
catalyzes the vicinal perfluoroalkylation–
iodination of arynes with perfluoroalkyl
iodides RfI (Rf =CF3, C2F5), representing
the first example of ionic atom-/group-
transfer reactions of both the perfluor-
oalkyl group and iodine atom from RfI
into a single molecule (see scheme).
&
&
Chem. Eur. J. 2014, 20, 1 – 6
www.chemeurj.org
6
ꢀ 2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ÝÝ These are not the final page numbers!