DDQ-Catalyzed Direct C(sp3)-H Amination of Alkylheteroarenes: Synthesis of Biheteroarenes under Aerobic and Metal-Free Conditions

Article abstract of DOI:10.1021/acscatal.7b04434

A strategy for oxidative Csp³-H/N-H cross-coupling is presented. This reaction successfully utilizes 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) and tert-butyl nitrite (TBN) as co-catalysts to construct the biomedical applicable biheteroarene

Full text of DOI:10.1021/acscatal.7b04434

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Letter
DDQ-Catalyzed Direct C(sp3)–H Amination of Alkylhet-eroarenes:
Synthesis of Biheteroarenes under Aerobic and Metal-free Conditions
Chunlan Song, Xin Dong, Hong Yi, Chien-Wei Chiang, and Aiwen Lei
ACS Catal., Just Accepted Manuscript • DOI: 10.1021/acscatal.7b04434 • Publication Date (Web): 03 Feb 2018
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ACS Catalysis
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DDQ-Catalyzed Direct C(sp3)–H Amination of Alkylhet-
eroarenes: Synthesis of Biheteroarenes under Aerobic and
Metal-free Conditions
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Chunlan Song†, Xin Dong†, Hong Yi†, Chien-Wei Chiang*† and Aiwen Lei*†‡
† College of Chemistry and Molecular Sciences, Institute for Advanced Studies (IAS), Wuhan University, Wuhan
430072, P. R. China
‡ National Research Center for Carbohydrate Synthesis, Jiangxi Normal University, Nanchang 330022, P. R. China
ABSTRACT: A strategy for the oxidative Csp3-H/N-H cross-coupling is presented. This reaction successfully utilizes DDQ
and TBN as the co-catalysts to construct the biomedical applicable biheteroarenes under aerobic conditions. Notably, this
amination reaction is successful with a wide range of alkylheteroarenes and could be used as a functionalization tactic for
pharmaceutical research and other areas. Furthermore, preliminary mechanistic studies indicate that the C-N bond
formation proceeds through the nucleophilic attack of azole to the carbon cation.
KEYWORDS: C(sp3)-H amination, C(sp3)-H/N-H cross-coupling, metal-free, biheteroarenes, alkylheterarenes, azoles
Biheteroarenes, possess a privileged structural cores in
organic functional materials, ligands, and biological
activities.1 The construction of biheteroarenes through the
C–H activation with two heteroaromatic units establishd
one of the most important subjects in organic chemistry.2
Notably, thiophene, an important molecular scaffold, is
frequently found in numerous natural products and func-
tional materials.3 Moreover, aminated alkylthiophenes by
utilizing azoles as the amination reagents are often em-
ployed as the building blocks in pharmaceuticals, such as
glucagon receptor antagonists, inhibitors of KV 1.5 and
inhibitors of ITK kinase (Scheme 1).4 Therefore, to discov-
er a sustainable way for the preparation of these valuable
aminated alkylthiophenes is important in organic synthe-
sis.
since it avoided the prefunctionalization steps of the
substrates.5 Nevertheless, due to the high bond energy
and low acidity, direct amination to accomplish the
C(sp3)–H to C–N bond formation regioselectively is still a
challenge.6 Recently, some C(sp3)-H bond amination
methods have been reported as attractive ways, such as
transition-metal catalysis,7 photo-catalysis,8 electro-
catalysis,9 iodine-catalysis.10 In contrast, developing met-
al-free, cheaper and catalytic amount of reagents’ systems
are of great importance. On the other hand, the amina-
tion products of alkylheteroarenes were useful for the
biological and pharmaceutical applications, such as ami-
nated alkylthiophenes, alkylfurans and alkylindoles. Un-
fortunately, the above catalysis methods lack of the ami-
nated reactions of these alkylheteroarenes. Our strategy
successfully utilized DDQ and TBN as the co-catalysts to
construct the biomedical applicable biheteroarenes under
aerobic condition with low cost and high efficiency
(Scheme 2).
H
DDQ, TBN, O2
N
X
N
N
Y
X
Y
N
X= S, O, N
Alkylheteroarenes
Y= N, CH
up to 99% yield
Scheme 1. Important molecules containing aminated
alkylthiophenes
Scheme 2. Strategy for amination of Csp3–H bonds
Over the past decade, C(sp2)-H/N-H direct cross-
coupling has been developed as one of the most
straightforward ways for the construction of C-N bonds
2,3-Dichloro-5,6-dicyano-p-benzoquinone (DDQ) is
known for facilitating
transformations, relying on its one-electron reduction
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a
number of C-H bond

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Page 2 of 6
c
potential and hydrogen abstraction capacity.11 In order to
achieve the C(sp3)-H amination of alkylheteroarenes, we
assumed that the reaction could be triggered by hydrogen
atom transfer (HAT) between alkylheteroarene 1 and
DDQ, and then generated the alkyl radical (I).
Subsequent oxidation led to the alkyl cation (II), which
reacted with pyrazole 2 to furnish the corresponding
amination product 3. Meanwhile, DDQH- could be
protonated to form the hydroquinone DDQH2. According
to previous works of Hu and our group, DDQH2 could be
oxidized to DDQ by NO2, which was generated from tert-
butyl nitrite (TBN) (Scheme 3).12
using biphenyl as an internal standard. N.D. implies that no
product could be detected by GC-MS and GC. d A nitrogen
balloon was used.
1
2
3
4
5
6
7
8
TBN catalysis system, the desired product 3a could be
obtained in 99% yield (Table 1, Entry 1). When other qui-
nones such as benzoquinone and tetra-chloro-
benzoquinone were used as the catalyst, no desired prod-
uct could be observed (Table 1, Entry 2-3). Due to the
lower redox potential, benzoquinone and tetra-chloro-
benzoquinone could not oxidize the substrate.13 As we
tried to decrease the loading of 2-ethylthiophene or cata-
lyst, the yield of this transformation showed slightly de-
crease (Table 1, Entry 4-5). Other common oxidants, such
as tert-butyl hydroperoxide, diacetoxyiodobenzene, sodi-
um periodate and potassium persulfate couldn’t promote
this reaction (Table 1, entries 6-9). Control experiments
showed that no desired product could be detected with-
out DDQ (Table 1, Entry 10). Besides, only a small amount
of product could be observed in the absence of TBN since
DDQ could not be regenerated (Table 1, Entry 11).
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With the optimized protocols in hand, the substrate
Table 2. Substrate scope of alkylheteroarenesa
R2
20 mol% DDQ,
20 mol%TBN, air
H
R1
R2
X
N
R1
N
Scheme 3. Our strategy for DDQ-catalyzed direct
C(sp3)–H amination of alkylheteroarenes
N
3 mL DCE, r.t., 12 h
X
N
Y
Y
1
2
3
1.8 eq.
0.3 mmol
We began to choose 2-ethylthiophene and 4-chloro-1H-
pyrazole as the substrates to perform the C–N formation
reaction. Fortunately, with the combination of DDQ and
O
S
S
S
N
N
N
N
N
N
Table 1. Conditions screening a
Cl
Cl
Cl
3c 77%b
3a 84%
3b 84%
OAc
COOMe
S
S
S
1
N
N
N
N
N
2
N
N
Cl
3d 90%b
Cl
3f 55%b
3e 79%b
Yield (%)b
(N1:N2= 3.2:1)
Entry Variation from the standard conditions
1
2
none
99
N.D. c
N.D.
73
Cl
S
S
N
N
S
1
N
N
benzoquinone instead of DDQ
tetra-chloro-benzoquinone instead of DDQ
15 mol% DDQ, 15 mol% TBN were used
1.5 eq. thiophene was used
N
2
N
3
Cl
Cl
N
3i 86%b
3h 63%b
4
3g
99%
(N1:N2= 1:1)
5
83
6 d
7 d
0.3 mmol TBHP was used as the oxidant
N.D.
N.D.
S
1
O
1
O
N
N
N
N
2
0.3 mmol PhI(OAc)2 was used as the oxi-
dant
N
2
N
N
N
8 d
9 d
10
11
0.3 mmol NaIO4 was used as the oxidant
N.D.
N.D.
N.D.
15
Cl
3j 71%b
3k 96%b
3l 64%
(N1:N2= 1.2:1)
(N1:N2= 1:1.5)
0.3 mmol K2S2O8 was used as the oxidant
N
no DDQ
no TBN
N
O
N
N
Cl
N
N
Cl
a
N
N
Standard conditions: reactions were performed with 1a
Cl
(0.54 mmol), 2a (0.3 mmol), DDQ (20 mol %, 0.06 mmol),
and TBN (20 mol %, 0.06 mmol) in 3 mL 1,2-dichloroethane
with an air balloon for 12 h. b GC yields were determined by
MeO
3m 41%
3n 99%
3o 90%
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a
Standard conditions as shown in table 1. Isolated yields
our delight, the current catalytic system was suitable for a
were shown. b 80 oC.
1
2
3
4
5
6
7
8
wide range of nitrogen sources. Multifarious benzotria-
zoles were well transferred into the corresponding prod-
ucts with two or three isomers, including different elec-
tron-donating or electron-withdrawing substituted ben-
zotriazoles (6a-6l). 5-Methyl-benzotriazole and 5-tert-
butylbenzotriazole gave the desired products in good
yields (6b-6c). Furthermore, the halide substituted prod-
ucts of benzotriazoles (6d-6f) could provide a handle of
further synthetic manipulations and no effect on halogen
group could be observed. A series of strong electron-
deficient substituted benzotriazoles such as trifluorome-
thyl, ester, nitro and cyanide groups were performed un-
der the standard conditions with up to 99% yield (6g-6j).
Then the presence of α-substituted or di-substituted ben-
zotriazoles were also well-tolerated (6k-6l). It was worth
noting that 4-phenyltriazole was suitable in this system,
achieving the C(sp3)-H amination product in good yield
(6m). What’s more, pyrazol and it’s derivatives also had
good reactivities and afforded the desired products in
high yields (6n-6s).
scope of this amination method was screened next (Table
2). Firstly, alkyl group in linear, alkenyl-containing, and
ester-containing alkylthiophenes could all be transferred
into aminated products as shown in Table 2. Amination of
linear system such as methyl and electron-donating
groups gave the corresponding products with good effi-
ciency, as illustrated by 3b-3d. Alkenyl substituent could
be tolerated in this transformation in 79% yield (3e). No-
tably, the electron-deficient alkylthiophene also afforded
the desired product in slightly diminished yield (3f). Me-
thyl- or chloro- substituted alkylthiophenes were reached
as well (3g-3h). Additionally, the amination product of 2-
ethyl-5-methylthiophene showed high selectivity between
methyl and ethyl group (3g). Moreover, 2-
ethylbenzo[b]thiophene and 3-ethylthiophene also could
be converted to the products (3i-3j). What’s more, other
alkylheteroarenes such as furans and indoles were toler-
ated with good efficiency (3k-3o). This synthesis pathway
could deliver an alternative option to synthesize the im-
portant molecules which contain the thiophenes, furans
or indoles.
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Table 4. Scope of nitrogen sources a
20 mol% DDQ,
H
20 mol%TBN, air
N
S
By utilizing this protocol, alkylarenes could also pro-
vide good efficiencies (Table 3). Moderate to good yields
were obtained with ethyl benzene derivatives (5a-5b). 2-
Ethylnaphthalene and diphenylmethane were given the
desired products in good yields (5c-5d). Cyclical sub-
strates could be reached as well such as fluorene and in-
dane (5e-5f).
N
N
S
3 mL DCE, r.t., 12 h
N
Y
Y
1a
1.8 eq.
2
6
0.3 mmol
tBu
1
1
N
3
1
N
N
N
N
N
2
2
N
2 N
N
3
6a 86%
(N1:N2= 1:1.7)
6b 70%
(N1:N2:N3= 1.6:1.3:1)
6c 75%
(N1:N2:N3= 1.6:1.2:1)
Table 3. Substrate scope of alkylarenes a
1
CF3
R= F, 6d 89% (N1:N2:N3= 1.7:1.3:1)
R= Cl, 6e 83% (N1:N2:N3= 1:1:1)
R= Br, 6f 99% (N1:N2:N3= 1.3:1:1)
N
N
1
R
N
N
N
3
2
2
N
3
6g 97%
(N1:N2:N3= 1.3:1.7;1)
1
2 N
3
1
1
COOMe
NO2
CN
N
N
N
N
N
N
N
2 N
3
2
3
6h 90%
6i 99%
6j 99%
(N1:N2:N3= 1:1.1:1.1)
(N1:N2:N3= 1.7:1.6:1)
(N1:N2:N3= 1.4:1.3:1)
1
1
N
Cl
Cl
1
N
N
N
2
N
N
2
2 N
N
3
N
Ph
3
6k 84%
(N1:N2:N3= 5.3:1:5)
6l 79%
(N1:N2= 1:1.9)
6m 69%
(N1:N2:N3= 3.3:2.6:1)
1
R= H, 6o 50%c
N
N
2
N
Ph
N
N
R= Br, 6p 90%
R= I, 6q 80%
N
I
Ph
R
6s 62%
(N1:N2= 2:1)
6n 83%b
R= NO2, 6r 80%
a
Standard conditions as shown in table 1. Isolated yields
a
Standard conditions as shown in table 1. Isolated yields
were shown. The ratio of the isomer was determined by NMR.
b Reaction was performed with 1a (0.6 mmol), 2 (0.3 mmol),
DDQ (30 mol %, 0.09 mmol), and TBN (30 mol %, 0.09
mmol) in 3 mL 1,2-dichloroethane with an air-balloon for 24
were shown. b 80 C. c Reaction was performed with 4 (0.9
o
mmol), 2 (0.3 mmol), DDQ (30 mol %, 0.09 mmol), and TBN
(30 mol %, 0.09 mmol) in 3 mL 1,2-dichloroethane with an
air-balloon at 100 oC for 24 h.
c
h. Reactions were performed with a solution of the 1a (0.54
mmol), DDQ (20 mol%, 0.06 mmol) and tert-butyl nitrite (20
mol%, 0.06 mmol) in 3 mL 1,2-dichloroethane with an air-
balloon for 12 h. Pyrazole (0.3 mmol) was dissolved in 0.2 ml
Consequently, nitrogen-containing heteroarenes were
also explored for the amination reactions (Table 4). To
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Page 4 of 6
DCE, then the solution was added to the reaction system for
1
four times when the reaction performed for 0, 2, 5, 8 h.
2
3
4
5
6
7
8
9
To further explore the utilities of this method for
constructing aminated alkylthiophene, we tried to expand
the reaction to gram scale. Reaction selectivity and yield
could still be well-obtained (Figure 1). Obviously, this
DDQ catalyzed oxidative system showed a great potential
according to the demand for metal-free, atom-economical
and sustainable chemistry.
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Figure 1. Gram scale reaction
As demonstrated, aminated alkylthiophenes, as synthe-
sized by the catalytic method reported herein, was uti-
lized in the synthesis of glucagon receptor antagonists
(Scheme 4). The coupling of compound A with B in pres-
ence of 30 mol% of DDQ and TBN produced aminated
alkylthiophene C in 85% yield. Then compound C under-
went acetylation with nBuLi and DMF to give the acetyl-
biheterocyclic compound D. A two-step manipulation
involving the oxidation and esteration furnished com-
pound E, a precursor of glucagon receptor antagonists in
good yield.
Figure 2. Mechanism studies for DDQ-catalyzed di-
rect C(sp3)–H amination of alkylheteroarenes, (a)
radical-inhibiting experiments; (b) nucleophile trap-
ping experiments.
a
0.225
0.200
0.175
0.150
0.125
0.100
0.075
0.050
0.025
0.000
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
[2-Ethylthiophene] per mol L-1
b
0.40
0.35
0.30
0.25
0.20
0.15
0.10
0.05
0.00
Scheme 4. The synthesis of Glucagon Receptor An-
tagonists
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
[DDQ] per mol L-1
In addition, to get insight into the reaction process, the
radical-inhibition studies were carried out. By adding 2
equiv. of 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) or
2,6-di-tert-butyl-4-methylphenol (BHT) as the radical
scavengers, the reaction processes were completely sup-
pressed, which revealed that a radical process was in-
volved in this reaction (Figure 2a). Moreover, methanol
and acetic acid were introduced to trap the in-situ gener-
ated alkyl cation. As a result, the alkoxide-bound adducts
were obtained, indicating that this transformation pro-
ceeded through a cation procedure (Figure 2b). Further-
more, kinetic studies of this reaction by detecting the
initial reaction rate with different loading of 2-
ethylthiophene and DDQ demonstrated that the sub-
strate and DDQ both followed the first-order dependen-
cies (Figure 3).
Figure 3. Kinetic plots of the reactions with different
concentrations of (a) 2-ethylthiophene 1a and (b)
DDQ catalyst.
In conclusion, we have developed a direct C(sp3)–H
amination of alkylheteroarenes by introducing a catalytic
amount of DDQ and electron mediator TBN under aero-
bic conditions. Broad alkylheteroarenes could be selec-
tively transformed into biheteroarenes in excellent yields,
with H2O as the only byproduct. Utilizing the aerobic and
metal-free strategy, a precursor of glucagon receptor an-
tagonists was able to be synthesized with good efficiency.
Additionally, in comparison with previous reports, this
protocol can successfully diminish the usage of metals
and equivalent oxidants.
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(6) (a) He, J.; Wasa, M.; Chan, K. S. L.; Shao, Q.; Yu, J.-Q.
Chem. Rev. 2017, 117, 8754-8786. (b) Park, Y.; Kim, Y.; Chang, S.
Chem. Rev. 2017, 117, 9247-9301.
ASSOCIATED CONTENT
Supporting Information
1
2
3
4
5
6
7
8
9
The Supporting Information is available free of charge on the
(7) (a) Gou, Q.; Liu, G.; Liu, Z.-N.; Qin, J. Chem. Eur. J. 2015, 21,
15491-15495. (b) He, G.; Zhao, Y.; Zhang, S.; Lu, C.; Chen, G. J. Am.
Chem. Soc. 2012, 134, 3-6. (c) He, J.; Shigenari, T.; Yu, J.-Q. Angew.
Chem. Int. Ed. 2015, 54, 6545-6549. (d) Nadres, E. T.; Daugulis, O.
J. Am. Chem. Soc. 2012, 134, 7-10. (e) Pan, J.; Su, M.; Buchwald, S.
L. Angew. Chem. Int. Ed. 2011, 50, 8647-8651. (f) Wang, A.;
Venditto, N. J.; Darcy, J. W.; Emmert, M. H. Organometallics
2017, 36, 1259-1268. (g) Zeng, L.; Tang, S.; Wang, D.; Deng, Y.;
Chen, J.-L.; Lee, J.-F.; Lei, A. Org. Lett. 2017, 19, 2170−2173.
(8) (a) Pandey, G.; Laha, R. Angew. Chem. Int. Ed. 2015, 54,
14875-14879. (b) Pandey, G.; Laha, R.; Singh, D. J. Org. Chem.
2016, 81, 7161-7171.
ACS Publications website at DOI: ***.
General information, experimental procedure,
mechanism studies, detailed descriptions for prod-
ucts, copies of product, references and NMR spectra
(PDF).
AUTHOR INFORMATION
Corresponding Author
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*E-mail: cwchiang@whu.edu.cn.
*E-mail: aiwenlei@whu.edu.cn.
(9) Hayashi, R.; Shimizu, A.; Song, Y.; Ashikari, Y.; Nokami, T.;
Yoshida, J.-i. Chem. Eur. J. 2017, 23, 61-64.
ORCID
(10) (a) Fan, R.; Li, W.; Pu, D.; Zhang, L. Org. Lett. 2009, 11,
1425-1428. (b) Kim, H. J.; Kim, J.; Cho, S. H.; Chang, S. J. Am.
Chem. Soc. 2011, 133, 16382-16385. (c) Xue, Q.; Xie, J.; Li, H.;
Cheng, Y.; Zhu, C. Chem. Commun. 2013, 49, 3700-3702. (d) Zhu,
C.; Liang, Y.; Hong, X.; Sun, H.; Sun, W.-Y.; Houk, K. N.; Shi, Z. J.
Am. Chem. Soc. 2015, 137, 7564-7567. (e) Lv, Y.; Li, Y.; Xiong, T.;
Lu, Y.; Liu, Q.; Zhang, Q. Chem. Commun. 2014, 50, 2367-2369.
(11) Wendlandt, A. E.; Stahl, S. S. Angew. Chem. Int. Ed. 2015,
54, 14638-14658.
(12) (a) Ohkubo, K.; Fujimoto, A.; Fukuzumi, S. J. Am. Chem.
Soc. 2013, 135, 5368-5371. (b) Shen, Z.; Dai, J.; Xiong, J.; He, X.; Mo,
W.; Hu, B.; Sun, N.; Hu, X. Adv. Synth. Catal. 2011, 353, 3031-3038.
(c) Shen, Z.; Sheng, L.; Zhang, X.; Mo, W.; Hu, B.; Sun, N.; Hu, X.
Tetrahedron Lett. 2013, 54, 1579-1583. (d) Song, C.; Yi, H.; Dou, B.;
Li, Y.; Singh, A. K.; Lei, A. Chem. Commun. 2017, 53, 3689-3692.
(13) (a) Jones, G.; Haney, W. A.; Phan, X. T. J. Am. Chem. Soc.
1988, 110, 1922-1929. (b) Fukuzumi, S.; Ohkubo, K.; Tokuda, Y.;
Suenobu, T J. Am. Chem. Soc. 2000, 122, 4286-4294. (c) Amatore,
C.; Cammoun, C.; Jutand, A. Adv. Synth. Catal. 2007, 349, 292-
296.
Aiwen Lei: 0000-0001-8417-3061
Chien-Wei Chiang: 0000-0001-9399-8284
Notes
The authors declare no competing financial interest.
ACKNOWLEDGMENT
This work was supported by the National Natural Science
Foundation of China (21390402, 21520102003). The Program
of Introducing Talents of Discipline to Universities of China
(111 Program) is also appreciated.
REFERENCES
(1) (a) Yang, Y.; Lan, J.; You, J. Chem. Rev. 2017, 117, 8787-8863.
(b) Correa, A.; Cornella, J.; Martin, R. Angew. Chem. Int. Ed. 2013,
52, 1878-1880. (c) Hassan, J.; Sévignon, M.; Gozzi, C.; Schulz, E.;
Lemaire, M. Chem. Rev. 2002, 102, 1359-1470.
(2) (a) Cho, S. H.; Kim, J. Y.; Kwak, J.; Chang, S. Chem. Soc. Rev.
2011, 40, 5068-5083. (b) Yeung, C. S.; Dong, V. M. Chem. Rev.
2011, 111, 1215-1292. (c) Liu, C.; Zhang, H.; Shi, W.; Lei, A. Chem.
Rev. 2011, 111, 1780-1824. (d) Liu, C.; Yuan, J.; Gao, M.; Tang, S.; Li,
W.; Shi, R.; Lei, A. Chem. Rev. 2015, 115, 12138-12204.
(3) Roncali, J. Chem. Rev. 1992, 92, 711-738.
(4) (a) Gilbert, E. J.; Michael, M. W.; Stamford, A. W.; Green-
lee, W. J. U.S. (2013), US 8470773 B2 20130625. (b) Vaccaro, W.;
Huynh, T.; Lloyd, J.; Atwal, K.; Finlay, H. J.; Levesque, P.; Conder,
M. L.; Jenkins-West, T.; Shi, H.; Sun, L. Bioorg. Med. Chem. Lett.
2008, 18, 6381-6385. (c) Brookfield, F.; Burch, J.; Goldsmith, R. A.;
Hu, B.; Lau, K. H. L.; Mackinnon, C. H.; Ortwine, D. F.; Pei, Z.;
Wu, G.; Yuen, P.; Zhang, Y. PCT Int. Appl. (2014), WO
2014023258 A1 20140213.
(5) (a) Kim, H.; Shin, K.; Chang, S. J. Am. Chem. Soc. 2014, 136,
5904-5907. (b) Wu, L.; Fleischer, I.; Jackstell, R.; Beller, M. J. Am.
Chem. Soc. 2013, 135, 3989−3996. (c) Fang, X.; Jackstell, R.; Beller,
M. Angew. Chem. Int. Ed. 2013, 52, 14089–14093. (d) Niu, L.; Yi, H.;
Wang, S.; Liu, T.; Liu, J.; Lei, A. Nat. Commun. 2017, 8, 14226-
14232. (e) Sorribes, I.; Junge, K.; Beller, M. Chem. Eur. J. 2014, 20,
7878–7883. (f) Hu, X.-Q.; Chen, J.-R.; Wei, Q.; Liu, F.-L.; Deng,
Q.-H.; Beauchemin, A. M.; Xiao, W.-J. Angew. Chem. Int. Ed.
2014, 53, 12163-12167. (g) Yi, H.; Niu, L.; Song, C.; Li, Y.; Dou, B.;
Singh, A. K.; Lei, A. Angew. Chem. Int. Ed. 2017, 56, 1120 –1124. (h)
Yi, H.; Zhang, G.; Wang, H.; Huang, Z.; Wang, J.; Singh, A. K.; Lei,
A. Chem. Rev. 2017, 117, 9016–9085. (i) Jiao, J.; Murakami, K.;
Itami, K. ACS Catal. 2016, 6, 610-633. (j) Hu, X.-Q.; Qi, X.; Chen,
J.-R.; Zhao, Q.-Q.; Wei, Q.; Lan, Y.; Xiao, W.-J. Nat. Commun.
2016, 7, 11188−111200. (k) Zhao, H.; Wang, M.; Su, W.; Hong, M.
Adv. Synth. Catal. 2010, 352, 1301-1306.
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