Palladium-Catalyzed C?H Silylation through Palladacycles Generated from Aryl Halides

Article abstract of DOI:10.1002/anie.201800330

A highly efficient palladium-catalyzed disilylation reaction of aryl halides through C?H activation has been developed for the first time. The reaction has broad substrate scope. A variety of aryl halides can be disilylated by three types of C?H activation, including C(sp²)?H, C(sp³)?H, and remote C?H activation. In particular, the reactions are also unusually efficient. The yields are essentially quantitative in many cases, even in the presence of less than 1 mol % catalyst and 1 equivalent of the silylating reagent under relatively mild conditions. The disilylated biphenyls can be converted into disiloxane-bridged biphenyls.

Full text of DOI:10.1002/anie.201800330

A Journal of the Gesellschaft Deutscher Chemiker
Angewandte
Chemie
International Edition
www.angewandte.org
Accepted Article
Title: Palladium-Catalyzed C-H Silylation through Palladacycles
Generated from Aryl Halides
Authors: Ailan Lu, Xiaoming Ji, Bo Zhou, Zhuo Wu, and Yanghui
Zhang
This manuscript has been accepted after peer review and appears as an
Accepted Article online prior to editing, proofing, and formal publication
of the final Version of Record (VoR). This work is currently citable by
using the Digital Object Identifier (DOI) given below. The VoR will be
published online in Early View as soon as possible and may be different
to this Accepted Article as a result of editing. Readers should obtain
the VoR from the journal website shown below when it is published
to ensure accuracy of information. The authors are responsible for the
content of this Accepted Article.
To be cited as: Angew. Chem. Int. Ed. 10.1002/anie.201800330
Angew. Chem. 10.1002/ange.201800330
Link to VoR: http://dx.doi.org/10.1002/anie.201800330
http://dx.doi.org/10.1002/ange.201800330

10.1002/anie.201800330
Angewandte Chemie International Edition
DOI: 10.1002/anie.201((will be filled in by the editorial staff))
C–H Activation
Palladium-Catalyzed C–H Silylation through Palladacycles Generated
from Aryl Halides
Ailan Lu,+ Xiaoming Ji,+ Bo Zhou, Zhuo Wu, and Yanghui Zhang *
rely on the use of directing groups.8 This strategy restricts the scope
Abstract: A highly efficient palladium-catalyzed disilylation reaction
of aryl halides through C–H activation has been developed for the
first time. The reaction has broad substrate scope. A variety of aryl
halides can be disilylated via three types of C–H activation,
including C(sp2)–H, C(sp3)–H, and remote C–H activation. In
particular, the reactions are also unusually efficient. The yields are
essentially quantitative in many cases, even in the presence of <1
mol% catalyst and 1 equiv of the silylating reagent under relatively
mild conditions. The disilylated biphenyls can be converted into
disiloxane-bridged biphenyls.
of accessible products. Therefore, the development of transient
directing groups has attracted considerable interest.9 Notably,
halogens have been exploited as transient directing groups to
activate C–H bonds. For Pd-catalyzed reactions of this type, the
reactions form palladacycles as the intermediates. Most of the
current reactions involve intramolecular cyclization,10 and
intermolecular reactions are quite rare.11 Our group has been
interested in this type of palladacycles,12 because they may exhibit
novel reactivity, and the two Pd–C bonds offer opportunities to
develop innovative reactions. Herein, we report extremely efficient
reactions of such palladacycles with hexamethyldisilane. This mode
of reactivity allows for efficient formation of disilylated products
with quantitative yields, very low catalyst loading, 1 equiv of
reactant, and broad substrate scope.
T
he past few decades have witnessed noticeable progress in the
development of transition-metal-catalyzed C–H functionalization.1
In this context, palladium catalysis is particularly attractive, and a
number of palladium-catalyzed reactions have been developed.2
However, the majority of Pd-catalyzed C–H functionalization
reactions suffer from high catalyst loading, limited substrate scope,
and imperfect yields. For intermolecular reactions, excess of the
reactants is often needed to achieve satisfactory yields. These issues
restrict application of these methods in organic synthesis. Therefore,
it is highly desirable to develop innovative C–H functionalization
protocols that provide excellent yields with broad substrate scope
using low catalyst loading and 1 equiv of both reaction partners.
We commenced our study by investigating the reaction of 2-
iodobiphenyl (1a) with hexamethyldisilane (2). Surprisingly,
disilylated product 3a was formed almost quantitatively when the
reaction was carried out using 2 equiv of 2 and 10 mol% of
Pd(OAc)2 (Table 1, entry 1). In transition-metal-catalyzed C–H
silylation reactions with 2, only one of the silyl groups is typically
incorporated into products, and the other one ultimately becomes
byproduct. In the present reaction, both of the silyl groups are
incorporated, so it not only provides a new disilylating method, but
Organosilicon compounds are widely used in organic synthesis3
and materials science4 and have also found applications in medicinal
chemistry.5 Therefore, the development of new methods for the
formation of C–Si bonds has been the topic of extensive
investigation. Although the C–H functionalization strategy has been
exploited to introduce silyl groups into organic molecules,6 it is
much less developed than the borylation of C–H bonds, and the
application of silylation of C−H bonds to synthetic chemistry has
been limited by the inefficiency of the silylation reaction.6a In
particular, Pd-catalyzed C–H silylation reactions are rare and remain
to be developed. Although several excellent reactions have been
developed, primarily by using bidentate directing groups,7 they
generally require an excess of silylating reagent hexamethyldisilane,
use high catalyst loading, and provide only moderate yields in the
majority of substrates.
also represents
a highly atom-economic example of C–H
functionalization. Gratifyingly, the yield was nearly quantitative
even using 1 mol% of Pd(OAc)2 and 1 equiv of 2 (entry 2), which
indicates that the disilylation reaction is extremely efficient. Notably,
a yield of 96% was still obtained even when the catalyst loading was
lowered to 0.1 mol% and the reaction was scaled up to 3.0 mmol
(entry 3). (For the detailed optimization tables see the Supporting
Information).
Table 1. Optimization of reaction conditions for the disilylation of 2-iodobiphenyl.
Transition-metal-enabled C–H functionalization reactions often
entry
solvent
DMF
DMF
DMF
Pd(OAc)2
10%
2 (equiv)
yield (%)[a]
98
[*]
A. Lu,[+] X. Ji,[+] B. Zhou, Z. Wu, Prof. Dr. Y. Zhang
School of Chemical Science and Engineering, Shanghai Key
Laboratory of Chemical Assessment and Sustainability, Tongji
University
1
2
3
2
1
1
1%
97 (94[b]
96[b],[c]
)
0.1%
1239 Siping Road, Shanghai 200092, China
E-mail: zhangyanghui@tongji.edu.cn
[a] The yields were determined by 1H NMR analysis of the crude reaction mixture. [b]
Yield of the isolated product. [c] 3.0 mmol of 1a, 0.1 mol% of Pd(OAc)2, 24 h.
[**] The work was supported by the National Natural Science
Foundation of China (No. 21672162 and No. 21372176). We
thank Prof. Jin-Quan Yu and Keary M. Engle (The Scripps
Research Insitute) for helpful discussions.
Next, we investigated the substrate scope of the disilylation
protocol. We first examined the compatibility of various functional
groups by investigating the reactions of 4’-substituted 2-
iodobiphenyls. As shown in Table 2, the yields were essentially
quantitative for a range of functional groups, including electron-
[+]
These authors contributed equally to this work.
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/anie.201xxxxxx.
1
This article is protected by copyright. All rights reserved.

10.1002/anie.201800330
Angewandte Chemie International Edition
donating and -withdrawing substituents (3b–3k). The performance
of 2-iodobiphenyls bearing substituents at other positions was also
examined. Substituents at 3’ or even 2’-positions did not affect the
high yields of the disilylation protocol (3l–3r). A range of substrates
with substituents on the iodo-bearing benzene ring or both of the
benzene rings could be disilylated with excellent yields (3t–3ab).
Substrates containing a pyrrole or thiophene ring also exhibited very
high reactivity (3ac and 3ad) and an indole ring was suitable (3ae).
functional groups were compatible (5b–5h), and fluoro and chloro
groups were well-tolerated (5i and 5j). All the reactions were high-
yielding, with most being quantitative. For sterically hindered
substrate 4l, 5k was formed as the final product. (For the mechanism
of this transformation see the Supporting Information). The ester
derivatives of 4b were suitable, although the yield of the substrate
containing one methyl group was low (5m and 5n). It should be
noted that the disilylation of 4a was also scalable and that the yield
remained quantitative even using 0.1 mol% of Pd(OAc)2 (5a).
Table 2. Disilylation of 2-iodobiphenyl derivatives.[a]
Table 3. Disilylation of 1-(tert-butyl)-2-bromobenzene derivatives.[a]
[a] All yields are of isolated products. [b] 2.5 mmol of 4a, 0.1 mol% of Pd(OAc)2, 0.2
mol% of P(o-tol)3, 24 h.
Recently, remote C–H activation initiated by an intramolecular
Heck-type cyclization has attracted considerable interest because the
strategy represents a means of expanding the substrate scope of C–H
functionalization.13 This type of reaction involves formation of
spiropalladacycle intermediates, which can undergo intramolecular
cyclization14 or intermolecular functionalization.15 We envisioned
that the spiropalladacycles formed via remote C–H activation could
also be captured by 2. Therefore, 2-phenylacrylamide 6a was
Table 4. Disilylation of 2-phenylacrylamide derivatives.[a]
[a] All yields are of isolated products.
C(sp3)–H bonds can also be activated by utilizing halogens as
transient directing groups, and the reactions form palladacycles
consisting of a C(sp2)–Pd–C(sp3) bonding motif. Likewise, most
examples in the literature involve intramolecular cyclization.10e-h
Intermolecular reactions are comparatively underdeveloped.11d-f
Encouraged by the disilylation reaction of 2-iodobiphenyls, we set
out to investigate the intermolecular reactions of palladacycles
obtained by C(sp3)−H activation with 2. Therefore, 1-(tert-butyl)-2-
iodobenzene was subjected to the above standard conditions.
Gratefully, the expected disilylated product 5a was obtained in 93%
yield. 1-(tert-Butyl)-2-bromobenzene 4a was also reactive, but the
yield was very low (16%). The yield was dramatically improved to
96% when 2 mol% of P(o-tol)3 was added (Table 3, 5a).
The substrate scope of the C(sp3)–H silylation protocol was then
[a] All yields are of isolated products.
examined (Table 3). Various electron-donating and -withdrawing
2
This article is protected by copyright. All rights reserved.

10.1002/anie.201800330
Angewandte Chemie International Edition
allowed to react with 2 under the standard conditions for the
disilylation of 2-iodobiphenyl. Although desired disilylated product
7a was formed in 86% yield, the yield was improved to 95% when
the reaction time was extended to 24 h (Table 4, 7a). Subsequently,
we examined the performance of various derivatives of acrylamides.
A range of 2-phenylacrylamides bearing various groups on the
benzene rings with the bromo group were reactive (7b–7h), and the
yields were excellent for most of the substrates. Substrates with
different substituents on the aryl ring linked to the double bond also
underwent the disilylation reaction in excellent yields (7i–7n).
Finally, changing the N-substituents did not affect the high reactivity
of the acrylamides (7o–7r).
bond (C(sp2)–Si or C(sp3)–Si) is first formed. (For the detailed
mechanism of all the three reactions see the Supporting Information).
Scheme 2. Proposed mechanism for the disilylation reactions.
It should be noted that disilylated arenes have potential
applications in materials science17 and medicinal chemistry.18 We
also explored other synthetic applications of the disilylated products
(Scheme 3). When compound 3a was treated with BBr3, disiloxane
3a-D was formed. Other derivatives such as 3k and 3v also
underwent this transformation. It should be noted that silicon-
bridged π-conjugated compounds including disiloxane-bridged
biphenyls are widely studied as OLED materials.19 Currently,
disiloxane-bridged biphenyls are usually synthesized with disilane
derivatives, which are prepared from 2,2'-diiodobiphenyls with t-
BuLi. Herein, we have developed a facile synthetic strategy starting
from 2-iodobiphenyls. Moreover, the aryl TMS group in the
products can be manipulated selectively. As shown in Scheme 3, the
aryl TMS group was transformed into the acetoxy or boronic acid
group with the alkyl TMS group intact,20 which demonstrates the
potential utility of the products in organic synthesis.
To gain insights into the mechanism of the disilylation reactions,
we prepared palladacycles derived from 1a (1a–Int) and 6a (6a–Int)
(Scheme 1). Both 1a–Int and 6a–Int reacted with 2, affording
disilylated products 3a and 7a, respectively. It is noted that 6a was
also disilylated to give 7a in 95% yield by using 1 mol% of 6a-Int
as the catalyst. Moreover, when equivalent amounts of 1a and 4-
iodotoluene were treated with 0.5 or 1 equiv of 2, 1a was still
transformed into 3a in high yields, whereas only trace amounts of 4-
trimethylsilyltoluene
were
obtained.
Furthermore,
4-
trimethylsiyltoluene was obtained in 9% yield when only 4-
iodotoluene was subjected to the standard conditions. These
experimental results indicate that the disilylation reactions should
proceed through palladacycle intermediates. In particular, the
palladacycles have far higher reactivity towards 2 than a simple
open-chain arylpalladium species and should be responsible for the
high efficiency of these disilylation reactions. The kinetic isotope
effect in the reaction was investigated. Whereas the intermolecular
KIE value was 1.0, the intramolecular KIE value was 5.7.
Furthermore, parallel reactions of 1a and 2',3',4',5',6'-
pentadeuterated 2-iodobiphenyl with 2 were carried out, and the KIE
value was 1.02. These results indicate that the turnover-limiting step
of the catalytic disilylation reaction did not involve C−H bond
activation. (For the detailed mechanistic studies see the Supporting
Information)
Scheme 3. Transformation of the synthetic products.
In conclusion, we have developed a novel protocol for Pd-
catalyzed C–H silylation. The palladacycles obtained through
various C–H activations act as the key intermediates and are
disilylated with hexamethyldisilane. The modular protocol has broad
substrate scope and is highly efficient. The disilylated biphenyls can
be converted into disiloxane-bridged biphenyls, and the aryl TMS
group can be transformed selectively. Further studies towards
understanding the detailed mechanism (in particular the origins of
the unusually high efficiency) and exploring this type of C–H
functionalization reaction are underway in our lab.
Scheme 1. Mechanistic studies.
On the basis of the products formed in the reactions, the above
mechanistic studies, and previous reports,7,16 we propose a tentative
mechanism for the Pd-catalyzed disilylation reactions. As shown in
Scheme 2, palladacycle A, which is formed through intramolecular
C–H activation from aryl halides, reacts with 2 via oxidative
addition to afford PdIV species B. Intermediate B undergoes
reductive elimination to yield intermediate D. An alternative
metathesis pathway cannot be excluded for the formation of D.
Finally, a second reductive elimination gives the disilylated product
and releases Pd0 species. For palladacycles consisting of a C(sp2)–
Pd–C(sp3) bonding motif, it remains to be investigated which C–Si
Received: ((will be filled in by the editorial staff))
Published online on ((will be filled in by the editorial staff))
Keywords: C–H activation · silylation · palladacycle · palladium
3
This article is protected by copyright. All rights reserved.

10.1002/anie.201800330
Angewandte Chemie International Edition
You, J. Am. Chem. Soc. 2014, 136, 4841; c) M. R. Albicker, N. Cramer,
Angew. Chem., Int. Ed. 2009, 48, 9139; d) R. Shintani, H. Otomo, K. Ota,
T. Hayashi, J. Am. Chem. Soc. 2012, 134, 7305; e) M. Chaumontet, R.
Piccardi, N. Audic, J. Hitce, J. L. Peglion, E. Clot, O. Baudoin, J. Am.
Chem. Soc. 2008, 130, 15157; f) S. Rousseaux, M. Davi, J. Sofack-
Kreutzer, C. Pierre, C. E. Kefalidis, E. Clot, K. Fagnou, O. Baudoin, J. Am.
Chem. Soc. 2010, 132, 10706; g) J.-X. Yan, H. Li, X.-W. Liu, J.-L. Shi, X.
Wang, Z.-J. Shi, Angew. Chem., Int. Ed. 2014, 53, 4945; h) M. Wang, X.
Zhang, Y.-X. Zhuang, Y.-H. Xu, T.-P. Loh, J. Am. Chem. Soc. 2015, 137,
1341.
[1]
a) C-H Activation (Eds.: J.-Q. Yu, Z. Shi), Springer, Heidelberg, 2010;
Most recent reviews: b) C. Liu, J. Yuan, M. Gao, S. Tang, W. Li, R. Shi, A
Lei, Chem. Rev. 2015, 115, 12138; c) T. Gensch, M. N. Hopkinson, F.
Glorius, J. Wencel-Delord, Chem. Soc. Rev. 2016, 45, 2900; d) G. Song, X.
Li, Acc. Chem. Res. 2015, 48, 1007; e) R. Shang, L. Ilies, E. Nakamura,
Chem. Rev. 2017, 117, 9086; f) O. Daugulis, J. Roane, L. D. Tran, Acc.
Chem. Res. 2015, 48, 1053; g) M. Moselage, J. Li, L. Ackermann, ACS
Catal. 2016, 6, 498; h) K. Murakami, S. Yamada, T. Kaneda, K. Itami,
Chem. Rev. 2017, 117, 9302; i) B. Olivier, Acc. Chem. Res. 2017, 50, 1114;
j) J. Miao, H. Ge, Eur. J. Org. Chem. 2015, 7859.
[11] a) S. Xu, R. Chen, Z. Fu, Q. Zhou, Y. Zhang, J. Wang, ACS Catal. 2017, 7,
1993. b) D. Masselot, J. P. H. Charmant, T. Gallagher, J. Am. Chem. Soc.
2006, 128, 694; c) T.-J. Hu, G. Zhang, Y.-H. Chen, C.-G. Feng, G.-Q. Lin,
J. Am. Chem. Soc. 2016, 138, 2897; d) G. Dyker, Angew. Chem., Int. Ed.
1992, 31, 1023; e) G. Dyker, Angew. Chem., Int. Ed. 1994, 33, 103; f)
ti e - onet li -He n nde i tin J. Am. Chem. Soc.
2016, 138, 6384;
[12] a) H. Jiang, Y. Zhang, D. Chen, B. Zhou, Y. Zhang, Org. Lett. 2016, 18,
2032; b) D. Chen, G. Shi, H. Jiang, Y. Zhang, Y. Zhang, Org. Lett. 2016,
18, 2130; c) G. Shi, D. Chen, H. Jiang, Y. Zhang, Y. Zhang, Org. Lett.
2016, 18, 2958; d) Z. Wu, D. Ma, B. Zhou, X. Ji, X. Ma, X. Wang, Y.
Zhang, Angew. Chem, Int. Ed. 2017, 56, 12288.
[13] V. P. Mehta, J.-A. García-López, ChemCatChem, 2017, 9, 1149.
[14] a) T. Piou, A. Bunescu, Q. Wang, L. Neuville, J. Zhu, Angew. Chem., Int.
Ed. 2013, 52, 12385; b) G. Satyanarayana, C. Maichle-Mössmer, M. E.
Maier, Chem. Commun. 2009, 1571; c) R. T. Ruck, M. A. Huffman, M. M.
Kim, M. Shevlin, W. V. Kandur, I. W. Davies, Angew. Chem., Int. Ed.
2008, 47, 4711.
[15] a) J. Ye, Z. Shi, T. Sperger, Y. Yasukawa, C. Kingston, F. Schoenebeck, M.
Lautens, Nat. Chem. 2016, 9, 361; b) H. Zheng, Y. Zhu, Y. Shi, Angew.
Chem., Int. Ed. 2014, 53, 11280; c) M. Pérez-Gómez, J.-A. García-López,
Angew. Chem., Int. Ed. 2016, 55, 14389; d) T. Gerfaud, L. Neuville, J. Zhu,
Angew. Chem., Int. Ed. 2009, 48, 572.
[16] a) B. L. Edelbach, R. J. Lachicotte, W. D. Jones, J. Am. Chem. Soc. 1998,
120, 2843; b) T. Matsuda, H. Kirikae, Organometallics 2011, 30, 3923.
[17] G. Schweicher, V. Lemaur, C. Niebel, C. Ruzié, Y. Diao, O. Goto, W.-Y.
Lee, Y. Kim, J.-B. Arlin, J. Karpinska, A. R. Kennedy, S. R. Parkin, Y.
Olivier, S. C. B. Mannsfeld, J. Cornil, Y. H. Geerts, Z. Bao, Adv. Mater.
2015, 27, 3066.
[18] J. O. Daiss, C. Burschka, J. S. Mills, J. G. Montana, G. A. Showell, I.
Fleming, C. Gaudon, D. Ivanova, H. Gronemeyer, R. Tacke,
Organometallics 2005, 24, 3192.
[19] a) H. Kai, J. Ohshita, S. Ohara, N. Nakayama, A. Kunai, I.-S. Lee, ,Y.-W.
Kwak, J. Organomet. Chem. 2008, 693, 3490; b) J. Ohshita, K. Murakami,
D. Tanaka, H. Yoshida, Heterocycles 2012, 86, 1167.
[20] a) K. Gondo, J. Oyamada, T. Kitamura, Org. Lett. 2015, 17, 4778; b) Y.
Qin, I. Kiburu, S. Shah, F. Jäkle, Org. Lett. 2006, 8, 5227.
[2]
[3]
[4]
a) J. J. Topczewski, M. S. Sanford, Chem. Sci. 2015, 6, 70; b) X. Chen, K.
M. Engle, D.-H. Wang, J.-Q. Yu, Angew. Chem. Int. Ed. 2009, 48, 5094; c)
J. Le Bras, J. Muzart, Chem. Rev. 2011, 111, 1170; d) R. Giri, S. Thapa, A.
Kafle, Adv. Synth. Catal. 2014, 356, 1395.
a) Chemistry of Organosilicon Compounds, Vol. 3 (Eds.: Z. Rappoport, Y.
Apeloig), Wiley-VCH, New York, 2001; b) Silicon in Organic,
Organometallic and Polymer Chemistry (Eds.: M. A. Brook), John Wiley
and Sons, New York, 2000.
a) Silicon Polymers (Eds.: A. M. Muzafarov), Springer, Heidelberg 2011;
b) Silicon-Containing Polymers (Eds.: R. G. Jones, W. Ando, J.
Chojnowski), Kluwer Academic, Dordrecht, 2000.
[5] a) M. Mortensen, R. Husmann, E. Veri, C. Bolm, Chem. Soc. Rev. 2009, 38,
1002; b) A. K. Franz, S. O. Wilson, J. Med. Chem. 2013, 56, 388.
[6]
a) C. Cheng, J. F. Hartwig, Chem. Rev. 2015, 115, 8946; b) J. F. Hartwig,
Acc. Chem. Res. 2013, 45, 864; c) C. Cheng, J. F. Hartwig, Science 2014,
343, 853; d) B. Lu, J. R. Falck, Angew. Chem., Int. Ed. 2008, 47, 7508; e)
E. M. Simmons, J. F. Hartwig, Nature 2012, 483, 70; f) F. Kakiuchi, K.
Tsuchiya, M. Matsumoto, E. Mizushima, N. Chatani, J. Am. Chem. Soc.
2004, 126, 12792; g) Q.-W. Zhang, K. An, L.-C. Liu, Y. Yue, W. He,
Angew. Chem. Int. Ed. 2015, 54, 6918; h) N. Ghavtadze, F. S. Melkonyan,
A. V. Gulevich, C. Huang, V. Gevorgyan, Nat. Chem. 2014, 6, 122; i) T.
Ureshino, T. Yoshida, Y. Kuninobu, K. Takai, J. Am. Chem. Soc. 2010,
132, 14324; j) H. Fang, W. Hou, G. Liu, Z. Huang, J. Am. Chem. Soc. 2017,
139, 11601.
[7] a) Y.-J. Liu, Y.-H. Liu, Z.-Z. Zhang, S.-Y. Yan, K. Chen, B.-F. Shi, Angew.
Chem. Int. Ed. 2016, 55, 13859; b) K. S. Kanyiva, Y. Kuninobu, M. Kanai,
Org. Lett. 2014, 16, 1968; c) C. Chen, M. Guan, J. Zhang, Z. Wen, Y.
Zhao, Org. Lett. 2015, 17, 3646; d) J.-L. Pan, Q.-Z. Li, T.-Y. Zhang, S.-H.
Hou, J.-C. Kang, S.-Y Zhang, Chem. Commun. 2016, 52, 13151; e) J.-L.
Pan, C. Chen, Z.-G. Ma, J. Zhou, L.-R. Wang, S.-Y. Zhang, Org. Lett.
2017, 19, 5216; f) A. Deb, S. Singh, K. Seth, S. Pimparkar, B. Bhaskararao,
S. Guin, R. B. Sunoj, D. Maiti, ACS Catal. 2017, 7, 8171; g) The only
example using monodentate directing groups: A. Modak, T. Patra, R.
Chowdhury, S. Raul, D. Maiti, Organometallics 2017, 36, 2418.
[8]
a) T. W. Lyons, M. S. Sanford, Chem. Rev. 2010, 110, 1147; b) K. M.
Engle, T.-S. Mei, M. Wasa, J.-Q. Yu, Acc. Chem. Res. 2012, 45, 788.
a) G. Rousseau, B. Breit, Angew. Chem., Int. Ed. 2011, 50, 2450; b) F. Z.
Zhang, D. R. Spring, Chem. Soc. Rev. 2014, 43, 6906.
[9]
[10] a) R. Deng, Y. Huang, X. Ma, G. Li, R. Zhu, B. Wang, Y.-B. Kang, Z. Gu,
J. Am. Chem. Soc. 2014, 136, 4472; b) D.-W. Gao, Q. Yin, Q. Gu, S.-L.
4
This article is protected by copyright. All rights reserved.

10.1002/anie.201800330
Angewandte Chemie International Edition
C–H Activation
A. Lu, X. Ji, B. Zhou, Z. Wu, Y. Zhang
* __________ Page – Page
Palladium-Catalyzed C–H Silylation
through Palladacycles Generated
from Aryl Halides
A palladium-catalyzed disilylation reaction of aryl halides has been developed
through C–H activation. The reaction has broad substrate scope and is unusually
efficient. A variety of aryl halides can be disilylated via three types of C–H
activation, including C(sp2)–H, C(sp3)–H, and remote C–H activation in excellent
yields, even in the presence of <1 mol% catalyst and 1 equiv of the silylating reagent.
5
This article is protected by copyright. All rights reserved.