Sequential Cross-Coupling/Annulation of ortho-Vinyl Bromobenzenes with Aromatic Bromides for the Synthesis of Polycyclic Aromatic Compounds

Article abstract of DOI:10.1002/anie.201910792

A sequential cross-coupling/annulation of ortho-vinyl bromobenzenes with aromatic bromides was realized, providing a direct and modular approach to access polycyclic aromatic compounds. A vinyl-coordinated palladacycle was proposed as the key intermediate for this sequential process. Excellent chemoselectivity and regioselectivity were observed in this transformation. The practicability of this method is highlighted by its broad substrate scope, excellent functional group tolerance, and rich transformations associated with the obtained products.

Full text of DOI:10.1002/anie.201910792

Angewandte
Communications
Chemie
International Edition: DOI: 10.1002/anie.201910792
German Edition: DOI: 10.1002/ange.201910792
À
C H Activation
Sequential Cross-Coupling/Annulation of ortho-Vinyl Bromobenzenes
with Aromatic Bromides for the Synthesis of Polycyclic Aromatic
Compounds
Dong Wei, Meng-Yao Li, Bin-Bin Zhu, Xiao-Di Yang, Fang Zhang,* Chen-Guo Feng,* and
Guo-Qiang Lin*
Abstract: A sequential cross-coupling/annulation of ortho-
vinyl bromobenzenes with aromatic bromides was realized,
providing a direct and modular approach to access polycyclic
aromatic compounds. A vinyl-coordinated palladacycle was
proposed as the key intermediate for this sequential process.
Excellent chemoselectivity and regioselectivity were observed
in this transformation. The practicability of this method is
highlighted by its broad substrate scope, excellent functional
group tolerance, and rich transformations associated with the
obtained products.
reactions without a mediator have been studied far less.
Several seminal examples were provided by Dyker and co-
workers, in which C(alkyl), C(aryl)-palladacycles generated
from ortho-methoxy or tertiary butyl substituted aryliodides
were supposed to be the key intermediates (Scheme 1a).[3]
A
sequential reaction can generate two or more chemical
bonds and quickly construct complex structures from simple
substrates in a single step, which is consistent with goals of
modern synthetic chemistry in pursuing more economic and
efficient organic transformations. Therefore, considerable
efforts have been focused on the design and implementation
of novel sequential processes.[1]
Cyclopalladated species with two carbon coordinating
atoms can undergo two cross-coupling steps to attain
functionalization of both carbon atoms, representing a power-
ful and reliable sequential synthetic strategy. Catellani-type
reactions are the most studied reactions following this
mechanism, where an intermediary molecule like norbornene
has to be added to generate the palladacycle and relay the
reactivity in the final cross-coupling step.[2] In contrast,
[*] Dr. D. Wei, Prof. X.-D. Yang, Prof. F. Zhang, Prof. C.-G. Feng,
Prof. G.-Q. Lin
The Research Center of Chiral Drugs, Innovation Research Institute
of Traditional Chinese Medicine, Shanghai University of Traditional
Chinese Medicine
Scheme 1. Application of palladacycles with two carbon coordinating
atoms for sequential reactions.
Shanghai 201203 (China)
E-mail: fzhang@shutcm.edu.cn
This approach was further developed by Zhang[4a,b] and
Luan.[4c] An alternative method for the generation of C-
(alkyl), C(aryl)-palladacycle was described by Lautens
fengcg@shutcm.edu.cn
lingq@sioc.ac.cn
Dr. D. Wei, M.-Y. Li, B.-B. Zhu, Prof. C.-G. Feng, Prof. G.-Q. Lin
Key Laboratory of Synthetic Chemistry of Natural Substances, Center
for Excellence in Molecular Synthesis, Shanghai Institute of Organic
Chemistry, University of Chinese Academy of Sciences, Chinese
Academy of Sciences
group,[5] where an intramolecular Heck/C H activation
À
process occurred, and has also been applied by Li,[6a]
Zhang,[4b] and the Yang and Liang group.[6b] Recently, the
application of C(aryl), C(aryl)-palladacycle generated from 2-
iodobiphenyls proved to be feasible, and a number of elegant
sequential processes were accomplished by Zhang and co-
workers (Scheme 1b).[7] Despite these advancements, the
application of C(vinyl), C(aryl)-palladacycle from vinyl-con-
taining substrates will be rather challenging due to the
existence of a reactive double bond in palladium catalysis,
and has not been reported yet.
Shanghai 200032 (China)
Prof. C.-G. Feng
Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs,
Shanghai Jiao Tong University
Shanghai 200240 (China)
Supporting information and the ORCID identification number(s) for
the author(s) of this article can be found under:
https://doi.org/10.1002/anie.201910792.
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Our group recently reported several 1,4-palladium migra-
tion reactions with ortho-vinyl bromobenzenes, where a C-
(vinyl), C(aryl)-palladacycle is proposed to be one of the key
intermediates.[8] As a continuation of this project, we herein
report the application of this species in the sequential cross-
coupling/annulation process with aromatic bromides for the
efficient synthesis of polycyclic aromatic compounds (Sche-
me 1c),[9,10] which are widely used in material sciences[11] as
well as in medicinal chemistry.[12]
With optimal reaction conditions identified, we then
explored the scope of ortho-vinyl bromobenzenes
1 (Scheme 2). In general, very good reaction yields were
observed for substrates bearing a phenyl ring A with different
Our initial experiments began with the reaction of ortho-
vinyl bromobenzene 1a and bromobenzene 2a (Table 1). To
our delight, the desired phenanthrene 3aa was generated in
41% reaction yield with Pd(OAc)2 as precatalyst, and PPh3
Table 1: Optimization of reaction conditions.[a]
Scheme 2. Reaction conditions: 1 (0.30 mmol), bromobenzene 2a
(0.45 mmol), Pd(OAc)2 (0.015 mmol), L8 (0.03 mmol) and K2CO3
(0.60 mmol) in dioxane (1.5 mL) at 1308C for 5 h unless otherwise
noted. Yields of isolated products are given. [a] The starting material
1 was an inseparable E/Z mixture, see Supporting Information for
details.
Entry Ligand Solvent Conversion [%][b] Yield of 3aa/4/5 [%][b]
1
2
3
4
5
6
7
8
9
10
11
12
13
14
L1
L2
L3
L4
L5
L6
L7
L8
L8
L8
L8
L8
L8
L1
DMF
DMF
DMF
DMF
DMF
DMF
DMF
DMF
CH3CN
DCE
94
26
84
91
54
74
83
100
61
68
41/30/11
11/10/4
28/–/12
36/41/12
28/15/6
27/32/9
27/25/17
40/29/8
29/–/7
18/–/4
20/–/–
16/–/–
90/–/–
steric and electronic profiles (3aa–3 fa). Substrates with the
phenyl ring A replaced by a pyridyl (3ga) or naphthyl (3ha)
were well tolerated, although the latter replacement resulted
in a reduced yield, likely due to the increased bulkiness of the
naphthyl ring. High reaction yields were also observed with
different substitutions on phenyl ring B (3ia–3ma). When
phenyl ring B was switched to a naphthyl (3na), pyridyl (3oa),
alkyl (3pa and 3qa) or ester (3ra) group, the reactions also
proceeded smoothly. Notably, instead of using a terminal
olefin, those bearing a methyl group on the terminal position
were accommodated, affording 9,10-disubstituted phenan-
threnes in acceptable yields (3sa and 3ta).
Next, a variety of aromatic bromides 2 was tested in the
sequential reaction (Scheme 3). Although slightly reduced
reaction yields were obtained for most examined substituted
bromobenzenes, excellent functional group tolerance was
observed. Chemically reactive substituents, such as SMe
(3ag), CHO (3ak), COCH3 (3al) and CO2Me (3am) can be
well accepted, providing handles for further transformations.
As expected, meta-methyl substitution gave rise to a pair of
regioisomers in a ratio of 45:55 due to the competitive
annulation step at these two positions (3ac + 3ac’). This
regioselectivity could be improved by using a larger substi-
tution group. Almost complete regioselectivity control was
achieved with meta-tBu substituted bromobenzene (3ad). By
using naphthyl and phenanthryl bromides, chrysene (3an) and
benzo[g]chrysene (3ao) structures were easily generated.
Owing to the strong coordinating ability, heterocyclic aryl
bromides could be problematic coupling partners. Pleasantly,
a wide range of heteroaromatic structures with different
substitution positions (Scheme 3), including isoquinoline
toluene
THF
dioxane
dioxane
30
23
100
100
83/–/–
[a] Reaction conditions: 1a (0.20 mmol), 2a (0.30 mmol), Pd(OAc)2
(0.01 mmol), L1-L3 (0.04 mmol) or L4-L8 (0.02 mmol), and K2CO3
(0.40 mmol) in dioxane (1.0 mL) at 1308C for 5 h unless otherwise
noted. [b] Determined by 1H NMR spectroscopy using CH2Br2 as an
internal standard.
(L1) as ligand (entry 1). However, a significant amount of
fluorene 4 was accompanied and several homo-coupling by-
products could be observed by GC-MS analysis. The major
one was identified to be the by-product 5. Ligand screening
did not give a higher yield of 3aa, but full conversion of the
starting material and a comparable result was obtained by
using DPEphos (L8) (entries 2–8). Solvent exerted a tremen-
dous influence on the reaction conversion and product
distribution. By-products could effectively be suppressed
when DMF was replaced by other solvents (entries 9–13). A
big leap in reaction yield was achieved by using dioxane as
solvent (entry 13). Additional efforts on reaction condition
optimization regarding base and temperature effects failed to
offer better results (see Supporting Information for details).
2
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Scheme 4. Studies on the synthetic utility.
step in 61% yield from the typical substrate 1a and the
commercially available arylbromide 12.
Finally, several experiments were carried out to gain
insights into the mechanism. The preparation of C(vinyl),
C(aryl)-palladated complex 13 was performed under the
standard reaction conditions (Scheme 5). While isolation of
the unstable intermediate was unsuccessful, it was captured
by SAESI-MS analysis, which is a direct and reliable method
for the characterization of reaction intermediates in situ
through a gentle ionization process.[17] An ion of m/z 809.1745
was detected with a high resolution SAESI-QTOF MS
instrument in positive mode. The experimental isotopic
Scheme 3. Reaction conditions: 1a (0.30 mmol), bromobenzene
(0.45 mmol), Pd(OAc)2 (0.015 mmol), L8 (0.030 mmol) and K2CO3
(0.60 mmol) in dioxane (1.5 mL) at 1308C for 5 h unless otherwise
noted. Yields of isolated products are given. [a] 1508C.
(3ap), quinoline (3aq, 3au, 3ay), benzo[d]thiazole (3ar),
quinoxaline (3at), pyridine (3as, 3ax), thiophene (3aw) and
benzofuran (3av), were well tolerated in this sequential
process. Excellent regioselectivities were also observed for
3at–3ay,[13] which is ascribed to the prominent difference
À
between two C H bonds for palladium promoted activation
in these heteroaromatic system.[14]
To illustrate the synthetic scope of this method, several
experiments were carried out. First, a gram-scale reaction was
performed, affording the product 3aa in high yield, consistent
with the small-scale trial (Scheme 4a). Second, the conversion
of several obtained products was tested (Scheme 4b). In light
of the power of palladium catalysis, the bromination of 3aa
and borylation of 3ai paved the way for preparing useful
building blocks for organic materials.[15] While the ester group
in 3ra is a useful site for further derivatization, it can also be
removed through a two-step operation (8). Finally, the power
of this method is further demonstrated by the synthesis of
compound 11 (Scheme 4c), which is a patented molecule used
in organic light-emitting diode electroluminescent devices
(OLEDs). The original synthetic route developed by the
company Merck, required five steps starting from multi-
halogenated benzene 9 with an overall yield of 13%.[16] In
sharp contrast, our method provided compound 11 in a single
Scheme 5. Reaction with in situ generated cyclopalladated species 13.
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distributions matched the theoretical, unambiguously indicat-
ing the existence of cyclopalladated species 13 (see Support-
ing Information for details). This in situ generated complex
was treated by bromobenzene 2a to afford phenanthrene 3aa
in 52% yield. In addition, the palladium species 13 can also be
observed through the detection of the reaction mixture
[Eq (1)] (see Supporting Information for details).
ortho-vinyl bromobenzene 1a to palladium catalyst
(step A), the desired C(vinyl), C(aryl)-palladacycle (II) will
À
be generated through a C H activation step (step B). The first
cross-coupling step with bromobenzene 2a (step C) then
takes place through either an oxidative addition[19] or
bimetallic pathway.[20] The resulting PdII species IV undergoes
À
a second C H activation and subsequently a reductive
elimination (step D and E) to afford the desired phenan-
threne 3aa. The intermediate IV may also be generated from
pathway II, where the reaction is initiated by oxidative
addition of bromobenzene 2a (step F) and subsequent Heck
reaction with 1a (step G). Although the second reaction
pathway could not be completely excluded, the first pathway
would be a preferred one based on the experimental data
discussed above.
In conclusion, we have developed a sequential cross-
coupling/annulation reaction of two different aromatic bro-
mides, providing a direct and modular approach to access
polycyclic aromatic compounds. High chemo- and regiose-
lectivity, broad substrate scope, and excellent functional
group tolerance were observed for this transformation. The
practicability of this method was further demonstrated by
a gram scale reaction and several useful product conversions,
as well as a concise synthesis of a patented molecule for
OLEDs. A C(vinyl), C(aryl)-palladacycle species is proposed
to be the key intermediate in this transformation and was
captured by SAESI-MS. Studies on the potential applications
of the method in material science are currently under way.
In view of the possible competition between two aryl-
bromides 1a and 2a in the initial oxidative addition step, we
reacted the prepared palladium complex 14 from bromoben-
zene with ortho-vinyl bromobenzene 1a and found only trace
amounts of product 3aa [Eq. (2)], which indicated that the
reaction through this intermediate is possible but rather
difficult.
The kinetic isotope effect was also measured. An inter-
molecular competition between bromobenzene and bromo-
benzene-d5 showed a kinetic isotope effect kH/kD = 1.68
À
(Scheme S4a), suggesting C H bond cleavage was involved
in the rate-determining step of the annulation. An intermo-
Acknowledgements
lecular competition between 1a and d2-1a revealed a small,
This work was supported by the National Natural Science
Foundation of China (21572253, 21672249, 21772216), the
Strategic Priority Research Program of the Chinese Academy
of Sciences (XDB 20020100), The Key Research Program of
Frontier Science (QYZDY-SSWSLH026), the State Admin-
istration of Traditional Chinese Medicine of People’s Repub-
lic of China (GZYYGJ2019059), the STCSM (18401933500)
and the SMEC (2019-01-07-00-10-E00072). We thank Dr.
Han-Qing Dong (Arvinas, Inc.) for his help in the preparation
of this manuscript.
À
perhaps secondary, isotope effect. In other words, C H bond
cleavage of 1a occurred as part of the mechanism, but did not
serve as a turnover-limiting step (Scheme S4b).[18]
Two possible reaction pathways were outlined in
Scheme 6. In pathway I, after the oxidative addition of
Conflict of interest
The authors declare no conflict of interest.
À
Keywords: C H activation · cross-coupling · palladacycles ·
palladium · polycyclic aromatic compounds
[1] For selected reviews on sequential reactions: a) C. M. Marson,
Chem. Soc. Rev. 2012, 41, 7712; b) C. M. Volla, I. Atodiresei, M.
Rueping, Chem. Rev. 2014, 114, 2390; c) X. Zeng, Chem. Rev.
2013, 113, 6864.
[2] For selected reviews on Catellani-type reactions: a) M. Catel-
lani, E. Motti, N. D. Caꢀ, Acc. Chem. Res. 2008, 41, 1512; b) A.
Scheme 6. Proposed reaction mechanism.
4
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Martins, B. Mariampillai, M. Lautens, Top. Curr. Chem. 2010,
2019, 58, 302; Angew. Chem. 2019, 131, 308; h) B.-B. Gou, H.
292, 1; c) H.-G. Cheng, S. Chen, R. Chen, Q. Zhou, Angew.
Chem. Int. Ed. 2019, 58, 5832; Angew. Chem. 2019, 131, 5890.
[3] a) G. Dyker, Angew. Chem. Int. Ed. Engl. 1992, 31, 1023; Angew.
Chem. 1992, 104, 1079; b) G. Dyker, Chem. Ber. 1994, 127, 739.
[4] a) Z. Wu, D. Ma, B. Zhou, X. Ji, X. Ma, X. Wang, Y. Zhang,
Angew. Chem. Int. Ed. 2017, 56, 12288; Angew. Chem. 2017, 129,
12456; b) A. Lu, X. Ji, B. Zhou, Z. Wu, Y. Zhang, Angew. Chem.
Int. Ed. 2018, 57, 3233; Angew. Chem. 2018, 130, 3287; c) B. Tan,
L. Bai, P. Ding, J. Liu, Y. Wang, X. Luan, Angew. Chem. Int. Ed.
2019, 58, 1474; Angew. Chem. 2019, 131, 1488.
[5] a) M. Sickert, H. Weinstabl, B. Peters, X. Hou, M. Lautens,
Angew. Chem. Int. Ed. 2014, 53, 5147; Angew. Chem. 2014, 126,
5247; b) J. Ye, Z. Shi, T. Sperger, Y. Yasukawa, C. Kingston, F.
Schoenebeck, M. Lautens, Nat. Chem. 2017, 9, 361.
[6] a) H.-Y. He, W. Wang, X.-J. Yu, J. Huang, L. Jian, H.-Y. Fu, X.-L.
Zheng, H. Chen, R.-X. Li, Eur. J. Org. Chem. 2016, 5616; b) X.
Luo, Y. Xu, G. Xiao, W. Liu, C. Qian, G. Deng, J. Song, Y. Liang,
C. Yang, Org. Lett. 2018, 20, 2997.
[7] 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) S. Pan, H. Jiang, Y. Zhang, D. Chen,
Y. Zhang, Org. Lett. 2016, 18, 5192.
[8] a) T.-J. Hu, G. Zhang, Y.-H. Chen, C.-G. Feng, G.-Q. Lin, J. Am.
Chem. Soc. 2016, 138, 2897; b) T.-J. Hu, M.-Y. Li, Q. Zhao, C.-G.
Feng, G.-Q. Lin, Angew. Chem. Int. Ed. 2018, 57, 5871; Angew.
Chem. 2018, 130, 5973; c) S.-S. Zhang, T.-J. Hu, M.-Y. Li, Y.-K.
Song, X.-D. Yang, C.-G. Feng, G.-Q. Lin, Angew. Chem. Int. Ed.
2019, 58, 3387; Angew. Chem. 2019, 131, 3425.
Yang, H.-R. Sun, J. Chen, J. Wu, L. Zhou, Org. Lett. 2019, 21, 80.
[11] For selected examples: a) R. Mitsuhashi, Y. Suzuki, Y. Yama-
nari, H. Mitamura, T. Kambe, N. Ikeda, H. Okamoto, A.
Fujiwara, M. Yamaji, N. Kawasaki, Y. Maniwa, Y. Kubozono,
Nature 2010, 464, 76; b) K. Takimiya, I. Osaka, T. Mori, M.
Nakano, Acc. Chem. Res. 2014, 47, 1493; c) G.-F. Zhang, H.
Wang, M. P. Aldred, T. Chen, Z.-Q. Chen, X. Meng, M.-Q. Zhu,
Chem. Mater. 2014, 26, 4433.
[12] For selected examples: a) G. M. Cragg, D. J. Newman, J. Nat.
Prod. 2004, 67, 232; b) L. Wei, Q. Shi, K. F. Bastow, A. Brossi,
S. L. Morris-Natschke, K. Nakagawa-Goto, T.-S. Wu, S.-L. Pan,
C.-M. Teng, K.-H. Lee, J. Med. Chem. 2007, 50, 3674; c) A.
Kovꢁcs, A. Vasas, J. Hohmann, Phytochemistry 2008, 69, 1084.
[13] CCDC 1908976 (3at), 1906210 (3au), 1908975 (3av) and 1906209
(3av) contain the supplementary crystallographic data for this
paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre.
[14] a) P. Guo, J. M. Joo, S. Rakshit, D. Sames, J. Am. Chem. Soc.
2011, 133, 16338; b) A. Petit, J. Flygare, A. T. Miller, G. Winkel,
D. H. Ess, Org. Lett. 2012, 14, 3680; c) X.-S. Xue, P. Ji, B. Zhou,
J.-P. Cheng, Chem. Rev. 2017, 117, 8622.
[15] For selected reviews on palladium-catalyzed cross-coupling for
synthesis of functional materials: a) B. Carsten, F. He, H. J. Son,
T. Xu, L. Yu, Chem. Rev. 2011, 111, 1493; b) A. H. Labulo, B. S.
Martincigh, B. Omondi, V. O. Nyamori, J. Mater. Sci. 2017, 52,
9225.
[16] L.-I Rodriguez, R. Linge, S. Meyer, H. Heil, WO 2017 036573
A1, 2017.
[17] a) J.-T. Zhang, H.-Y. Wang, W. Zhu, T.-T. Cai, Y.-L. Guo, Anal.
Chem. 2014, 86, 8937; For reviews: b) V. B. Di Marco, G. G.
Bombi, Mass Spectrom. Rev. 2006, 25, 347; c) K. L. Vikse, Z.
Ahmadi, J. S. McIndoe, Coord. Chem. Rev. 2014, 279, 96; d) A.
Ray, T. Bristow, C. Whitmore, J. Mosely, Mass Spectrom. Rev.
2018, 37, 565.
[18] For reviews: a) M. Gꢂmez-Gallego, M. A. Sierra, Chem. Rev.
2011, 111, 4857; b) E. M. Simmons, J. F. Hartwig, Angew. Chem.
Int. Ed. 2012, 51, 3066; Angew. Chem. 2012, 124, 3120.
[19] a) P. Sehnal, R. J. K. Taylor, I. J. S. Fairlamb, Chem. Rev. 2010,
110, 824; b) L.-M. Xu, B.-J. Li, Z. Yang, Z.-J. Shi, Chem. Soc.
Rev. 2010, 39, 712.
[9] For selected reviews: a) Y. Shen, C.-F. Chen, Chem. Rev. 2012,
112, 1463; b) R. Pratap, V. J. Ram, Chem. Rev. 2014, 114, 10476;
c) Y. Luo, X. Pan, X. Yu, J. Wu, Chem. Soc. Rev. 2014, 43, 834;
d) Y. Segawa, T. Maekawa, K. Itami, Angew. Chem. Int. Ed.
2015, 54, 66; Angew. Chem. 2015, 127, 68; e) Y. Yang, M.
Nishiura, H. Wang, Z. Hou, Coord. Chem. Rev. 2018, 376, 506;
f) H. Ito, Y. Segawa, K. Murakami, K. Itami, J. Am. Chem. Soc.
2019, 141, 3.
[10] For selected examples: a) D. C. Harrowven, I. L. Guy, L.
Nanson, Angew. Chem. Int. Ed. 2006, 45, 2242; Angew. Chem.
2006, 118, 2300; b) Z. Liu, R. C. Larock, Angew. Chem. Int. Ed.
2007, 46, 2535; Angew. Chem. 2007, 119, 2587; c) A. Matsumoto,
L. Ilies, E. Nakamura, J. Am. Chem. Soc. 2011, 133, 6557;
d) W. C. Fu, Z. Wang, W. T. K. Chan, Z. Lin, F. Y. Kwong,
Angew. Chem. Int. Ed. 2017, 56, 7166; Angew. Chem. 2017, 129,
7272; e) T. Kitamura, K. Gondo, J. Oyamada, J. Am. Chem. Soc.
2017, 139, 8416; f) H. Kitano, W. Matsuoka, H. Ito, K. Itami,
Chem. Sci. 2018, 9, 7556; g) J. Yin, J. You, Angew. Chem. Int. Ed.
[20] D. J. Cꢁrdenas, B. Martꢃn-Matute, A. M. Echavarren, J. Am.
Chem. Soc. 2006, 128, 5033.
Manuscript received: August 23, 2019
Accepted manuscript online: September 6, 2019
Version of record online: && &&, &&&&
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Communications
À
C H Activation
D. Wei, M.-Y. Li, B.-B. Zhu, X.-D. Yang,
F. Zhang,* C.-G. Feng,*
G.-Q. Lin*
&&&& — &&&&
Sequential Cross-Coupling/Annulation of
ortho-Vinyl Bromobenzenes with
Aromatic Bromides for the Synthesis of
Polycyclic Aromatic Compounds
Palladium catalysis: A sequential cross-
coupling/annulation of ortho-vinyl bro-
mobenzenes with aromatic bromides is
realized in a direct and modular approach
to access polycyclic aromatic com-
species is proposed as the key inter-
mediate. High chemo- and regioselectiv-
ity, broad substrate scope, and excellent
functional group tolerance are observed
for this transformation.
pounds. A C(vinyl), C(aryl)-palladacycle
6
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