Palladium-catalyzed direct C2 arylation of N-substituted indoles with 1-aryltriazenes

Article abstract of DOI:10.1002/asia.201402274

A novel and efficient palladium-catalyzed C2 arylation of N-substituted indoles with 1-aryltriazenes for the synthesis of 2-arylindoles was developed. In the presence of BF₃?OEt₂ and palladium(II) acetate (Pd(OAc)₂), N-substituted indoles reacted with 1-aryltriazenes in N,N-dimethylacetamide (DMAC) to afford the corresponding aryl-indole-type products in good to excellent yields.

Full text of DOI:10.1002/asia.201402274

FULL PAPER
DOI: 10.1002/asia.201402274
Palladium-Catalyzed Direct C2 Arylation of N-Substituted Indoles with 1-
Aryltriazenes
Can Liu,[a] Tao Miao,[a] Lei Zhang,[a] Pinhua Li,[a] Yicheng Zhang,[a] and Lei Wang*[a, b]
Abstract: A novel and efficient palladium-catalyzed C2 arylation of N-substituted
indoles with 1-aryltriazenes for the synthesis of 2-arylindoles was developed. In
the presence of BF3·OEt2 and palladium(II) acetate (Pd(OAc)2), N-substituted in-
doles reacted with 1-aryltriazenes in N,N-dimethylacetamide (DMAC) to afford
Keywords: arylation
coupling · heterocycles · homoge-
neous catalysis · palladium
·
cross-
G
the corresponding aryl–indole-type products in good to excellent yields.
Introduction
a series of different functionalities after treatment with the
appropriate reagents.[11] In addition, they also have been em-
ployed as electrophilic partners in transition-metal-catalyzed
carbon–carbon cross-coupling reactions. For example, Sen-
gupta et al. disclosed that aromatic triazenes were good cou-
pling partners in Heck-type reactions.[12] Subsequently,
Brꢀse et al. extended their methodology to solid-phase or-
ganic synthesis.[13] Tamao et al. developed a palladium-cata-
lyzed cross-coupling reaction of 1-aryltriazenes with arylbor-
onic acids and aryltrifluorosilanes under mild reaction con-
ditions.[14] However, the application of 1-aryltriazenes in the
The arylation of indoles has been and continues to be
a focus of research efforts for synthetic organic chemists be-
cause the arylated indoles are important building blocks in
natural products, pharmaceuticals, and synthetic functional
materials.[1] Over the past several years, the transition-
ꢀ
metal-catalyzed direct C H arylation of indoles with activat-
ed arenes has been successfully achieved, which provides an
efficient approach for the straightforward synthesis of aryl–
indole units without the need for prior functionalization of
indoles (i.e., halogenation or stoichiometric metalation).[2]
A
reaction of direct C H arylation of heteroaromatics is still
ꢀ
variety of arylating agents, including organic halides,[3] orga-
noboranes,[4] hypervalent iodines,[5] arylsiloxanes,[6] aromatic
carboxylic acids,[7] and arenes[8] have been explored in the
direct arylation reaction of indoles. More recently, we and
others reported that arylsulfinic acids (salts) were good cou-
pling partners in the direct C-arylation of indoles in the
presence of palladium catalyst.[9] Despite remarkable advan-
ces in this type of transformation, the establishment of new
and efficient synthetic methods for the preparation of aryl–
indoles with high selectivity at the 2-position (not at the 3-
position) from readily available and simple aryl sources is
highly desirable from both scientific and practical stand-
points.
unexplored. Herein, we wish to report a new and practical
method for the synthesis of 2-arylindoles through palladium-
catalyzed C2 arylation of N-substituted indoles with 1-aryl-
triazenes in the presence of boron trifluoride, thereby pro-
viding the desired aryl–indole-type products in good to ex-
cellent yields (Scheme 1).
Aromatic triazenes, which are very useful and versatile in-
termediates in organic synthesis, can be readily prepared
from the corresponding arylamines by means of a simple
one-step procedure.[10] They also can be converted into
Scheme 1. Pd-catalyzed C2 arylation of indoles with 1-aryltriazenes.
Results and Discussion
In our initial study, N-methylindole (1a) and 1-(p-tolyl)tria-
zene (2a) were chosen as model substrates to survey the re-
action parameters. It was found that the catalysts, additives,
and solvents play a critical role in the model reaction.
Boron trifluoride (BF3) is an efficient reagent to enhance
the reactivity of aryltriazenes in palladium-catalyzed cross-
coupling reactions.[14a] We also attempted this arylated reac-
tion using boron trifluoride as an additive to promote the
reaction. As shown in Table 1, when palladium(II) acetate
[a] C. Liu, T. Miao, L. Zhang, Prof. P. Li, Y. Zhang, Prof. L. Wang
Department of Chemistry, Huaibei Normal University
Huaibei, Anhui 235000 (P.R. China)
Fax : (+86)561-3090518
E-mail: leiwang@chnu.edu.cn
[b] Prof. L. Wang
State Key Laboratory of Organometallic Chemistry
Shanghai Institute of Organic Chemistry
Shanghai 200032 (P.R. China)
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/asia.201402274.
(PdACHTNUTGRNENUG(OAc)2) was used as a catalyst with BF3·OEt2 as an addi-
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Lei Wang et al.
Table 1. Palladium-catalyzed direct C2 arylation of N-methylindole with
1-(p-tolyl)triazene under various conditions.[a]
AHCTUNGTREN(GNUN PPh3)2Cl2]) gave inferior results (Table 1, entries 17–20).
When the catalyst loading was reduced from 2.5 to
1.0 mol%, the reaction afforded the desired product in 48%
yield (Table 1, entry 21). However, N-methylindole (1a) did
not react with 1-(p-tolyl)triazene (2a) in the absence of
either the palladium catalyst or the Lewis acid additive. It
was indicated that PdACHTUNGTRNEGNU(OAc)2 and BF3·OEt2 were essential
Entry
Pd catalyst
Pd(OAc)2
Pd(OAc)2
(OAc)2
(OAc)2
(OAc)2
(OAc)2
(OAc)2
(OAc)2
(OAc)2
(OAc)2
(OAc)2
(OAc)2
(OAc)2
(OAc)2
(OAc)2
(PPh3)4]
[Pd2A(dba)3]
PdCl2
(CH3CN)2Cl2]
[Pd(PPh3)2Cl2]
Additive
Solvent
Yield [%][b]
for the direct C2 arylation of N-substituted indoles with 1-
aryltriazenes (Table 1, entries 22 and 23). Although aryldia-
zonium salts, as a precursor of 1-aryltriazenes, have been
widely used as aryl reagents in organic synthesis, only 30%
yield of 3a was obtained when p-tolyldiazonium tetrafluoro-
borate was employed in the reaction with 1a under standard
reaction conditions (Table 1, entry 24).
1
2
3
4
5
6
7
8
G
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
FeCl3
DMF
DMAC
NMP
DMSO
CH3OH
CH3CO2H
CH3CN
toluene
dioxane
THF
60
92
80
ACHTUNGTRENNUNG
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
Pd
E
N
64
E
NR[c]
NR
11
ACHTUNGTRENNUNG
ACHTUNGTRENNUNG
A
trace
NR
NR
NR
NR
NR
NR
NR
73
60
50
47
27
With the optimized reaction conditions (2.5 mol% of Pd-
AHCTUNGTERN(GNUN OAc)2, BF3·OEt2 (1 equiv), DMAC, 808C, 12 h) in hand,
9
ACHTUNGTRENNUNG
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
ACHTUNGTRENNUNG
this Pd-catalyzed direct C2 arylation of indole was then ex-
tended to a wide array of 1-aryltriazenes and various indoles
to explore the scope and limitation of the reaction. As can
be seen from Scheme 2, the reactions of N-methylindole
(1a) with a wide range of 1-aryltriazenes proceeded well
and generated the desired products in good to excellent
yields. 1-Aryltriazenes with electron-rich groups, including
methyl, ethyl, isopropyl, methoxy, and ethoxy on the ben-
zene rings reacted with 1a efficiently and afforded the de-
sired products 3a–j in 81–95% yields. In contrast, the elec-
tron-deficient 1-aryltriazenes presented relatively lower re-
activity, and the corresponding arylated products 3k and 3l
were obtained in 74 and 65% yields, respectively. It is nota-
ble that the steric-hindrance effect was not clear when
ortho-substituted 1-aryltriazene was used as one of the sub-
strates in the reaction (3d, 82% yield).[4b,5a] Meanwhile, tria-
zenes that bear cyclic side chains, such as five-membered
pyrrolidine and six-membered piperidine, were also good
substrates for this arylation reaction and generated the
product 3a in 87 and 82% yields.
The substrate scope with respect to indoles was also inves-
tigated. A series of functional groups, such as methyl, me-
thoxy, fluoro, chloro, bromo, and ester were tolerated under
the optimal reaction conditions, and the desired products
3m–u were obtained in 57–85% yields. It should be noted
that N-ethylindole, N-propylindole, N-butylindole, and N-
benzylindole also reacted with 1-aryltriazenes efficiently,
and the corresponding products 3v–y were obtained in 77–
87% yields. Furthermore, some steric bulk indoles, such as
1,3-dimethylindole, 1-ethyl-3-methylindole, and 1-butyl-3-
methylindole were arylated with 2a smoothly to generate
3z, 3aa, and 3ab in 95, 89, and 87% yields, respectively.
Although the mechanism of this reaction has not been
clear up to now, on the basis of previous literature[3a,l,9,14a]
and the above observations, we propose a possible pathway
as shown in Scheme 3. In the presence of BF3·OEt2, the
formed triazene–BF3 complex A is followed by the genera-
tion of arenediazonium salt B.[11b] Then, oxidative addition
U
CH2Cl2
DCE
ACHTUNGTRENNUNG
N
DMAC
DMAC
DMAC
DMAC
DMAC
DMAC
DMAC
DMAC
DMAC
DMAC
DMAC
DMAC
R
CuCl2
AlCl3
A
[Pd
A
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
BF3·OEt2
–
R
G
[Pd
A
G
Pd
N
48[d]
NR
NR
30[e]
–
Pd
Pd
ACHTUNGTRENNUNG
A
BF3·OEt2
[a] Reaction conditions: 1a (0.50 mmol), 2a (0.60 mmol), Pd catalyst
(2.5 mol%), additive (0.50 mmol), solvent (2.0 mL), 808C, 12 h. [b] Iso-
lated yield. [c] NR=no reaction. [d] 1.0 mol% PdACTHNURTGNENG(U OAc)2 was used. [e] p-
Tolyldiazonium tetrafluoroborate was used as substrate instead of 2a.
tive and DMF as a solvent, the reaction of 1a with 2a gener-
ated the corresponding arylated product, 3a, in 60% yield
(Table 1, entry 1). Much to our pleasure, 92% isolated yield
of 3a was obtained when N,N-dimethylacetamide (DMAC)
was used as solvent instead of DMF (Table 1, entry 2). Fur-
ther screening of solvents revealed that DMAC was the best
solvent, and other polar solvents, such as N-methyl-2-pyrro-
lidone (NMP) and DMSO were also effective and provided
3a in good yields, but ethanol and acetic acid were harmful
to this arylation (Table 1, entries 3–6). Several low-polar sol-
vents including acetonitrile, toluene, dioxane, dichloro-
ethane (DCE), dichloromethane, and tetrahydrofuran
(THF) were also examined; all of them were improper sol-
vents and the model reaction was almost prohibited
(Table 1, entries 7–12). The effect of a Lewis acid was inves-
tigated on the model reaction by using FeCl3, CuCl2, and
AlCl3 in place of BF3·OEt2, and the results showed that no
desired product 3a was obtained (Table 1, entries 13–15).
Among the palladium species tested, [Pd
good activity, and 3a was isolated in 73% yield (Table 1,
entry 16), whereas other palladium catalysts (i.e., [Pd2A(dba)3]
(CH3CN)2Cl2], [Pd-
ACHTUNGTRENN(NUG PPh3)4] exhibited
ꢀ
of the Ar N bond in an arenediazonium salt (B) with in situ
U
generated Pd0 affords an arylpalladium cation C, which
reacts with 1a in the C2-position, thereby providing inter-
(dba=dibenzylideneacetone), PdCl2, [PdACHTGNUTRENNUNG
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Lei Wang et al.
Scheme 3. The proposed reaction mechanism.
Conclusion
In summary, we have developed a palladium-catalyzed effi-
cient method for the direct C2 arylation of indoles with 1-ar-
yltriazenes in the presence of BF3·OEt2. To the best of our
ꢀ
knowledge, this is the first C H arylation of indoles using 1-
aryltriazenes as the aryl source by means of a Pd-catalyzed
cross-coupling process. This new arylation provides an alter-
native means of access to a broad spectrum of C2 arylated
indoles in good to excellent yields. The investigation of a de-
tailed reaction mechanism and 1-aryltriazenes as coupling
species in other reactions is underway.
Experimental Section
General
All 1H and 13C NMR spectra were recorded with 400 MHz Bruker FT-
NMR spectrometers (400 or 100 MHz, respectively). All chemical shifts
are given as d values [ppm] with reference to tetramethylsilane (TMS) as
an internal standard. The chemicals and solvents were purchased from
commercial suppliers either from Aldrich, USA or the Shanghai Chemi-
cal Company, China. Products were purified by flash chromatography on
100–200 mesh silica gels (SiO2).
Typical procedure for synthetic aryltriazenes[11b]
A solution of primary arylamine (4.0 mmol) in HCl (aqueous, 37%,
2.0 mL) was cooled in an ice bath while a solution of NaNO2 (310 mg,
4.5 mmol) in cold water (8.0 mL) was added dropwise. The resulting solu-
tion of the diazonium salt was stirred at 08C for 30 min and then added
to a solution of diethylamine (1.46 g, 20.0 mmol) and K2CO3 (6.91 g,
50.0 mmol) in acetonitrile/water (1:2, 20.0 mL) in one portion. The reac-
tion mixture was allowed to warm to room temperature and stirred for
30 min. The aqueous phase was extracted with ethyl acetate (3ꢂ10 mL).
The organic phase was washed twice with brine, dried with MgSO4, and
concentrated under reduced pressure. The crude product was purified by
flash column chromatography over silica gel to give the corresponding ar-
yltriazene.
Scheme 2. Palladium-catalyzed direct C2 arylation of N-substituted in-
doles with 1-aryltriazenes.[a] Reaction conditions: a) 1 (0.50 mmol), 2
(0.60 mmol), PdACHTUNGTRENNUNG(OAc)2 (2.5 mol%), BF3·OEt2 (0.50 mmol), DMAC
(2.0 mL), 808C, 12 h. b) Yields of isolated products. c) 1-(Phenyldiaze-
nyl)pyrrolidine was used instead of 2a. d) 1-(Phenyldiazenyl)piperidine
was used instead of 2a.
Typical procedure for the C2 arylation of N-substituted indoles
A 10 mL sealable reaction tube with a Teflon-coated cap equipped with
a magnetic stir bar was charged with N-substituted indole (1, 0.50 mmol),
PdACTHNUTRGEN(NUG OAc)2 (0.0125 mmol), and DMAC (2.0 mL), then 1-aryltriazene (2,
mediate D. Finally, a reductive elimination from intermedi-
ate D produces the final coupling product 3 and Pd0 species,
thus finishing the catalytic cycle. However, we cannot rule
out the electrophilic substitution of the indole ring at the
C3-position followed by a C3!C2 migration.[3a,4d]
0.60 mmol) and BF3·OEt2 (0.50 mmol) were added by syringe. The reac-
tion mixture was stirred at 808C for 12 h. After the reaction was complet-
ed, it was cooled to room temperature, quenched with water, and extract-
ed with ethyl acetate. The organic phase was dried over MgSO4, filtered,
and concentrated under reduced pressure to yield the crude product,
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Lei Wang et al.
which was further purified by flash chromatography on silica gel with
ethyl acetate/petroleum ether (50:1!20:1) to provide the corresponding
product (3).
(t, J=7.3 Hz, 1H), 7.04 (d, J=8.2 Hz, 2H), 6.55 (s, 1H), 3.91 (s, 3H),
3.76 ppm (s, 3H); 13C NMR (100 MHz, CDCl3): d=159.5, 141.4, 138.1,
130.6, 128.0, 125.3, 121.4, 120.2, 119.7, 113.9, 109.5, 101.0, 55.3, 31.0 ppm.
1-Methyl-(p-tolyl)-1H-indole (3a)[4b]
2-(4-Ethoxyphenyl)-1-methyl-1H-indole (3j)
1
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.66 (d, J=7.8 Hz, 1H),
Colorless solid; H NMR (400 MHz, CDCl3): d=7.80 (d, J=7.6 Hz, 1H),
7.46 (d, J=8.5 Hz, 2H), 7.38 (d, J=8.2 Hz, 1H), 7.29–7.25 (m, 1H), 7.17
(t, J=7.4 Hz, 1H), 7.02 (d, J=8.5 Hz, 2H), 6.54 (s, 1H), 4.13 (q, J=
6.9 Hz, 2H), 3.76 (s, 3H), 1.49 ppm (t, J=6.9 Hz, 3H); 13C NMR
(100 MHz, CDCl3): d=158.8, 141.5, 138.1, 130.6, 128.0, 125.1, 121.3,
120.2, 119.7, 114.5, 109.5, 100.9, 63.5, 31.0, 14.8 ppm; HRMS (ESI): m/z
calcd for C17H18NO: 252.1388 [M+H]+; found: 252.1388.
7.56 (d, J=7.8 Hz, 2H), 7.50 (d, J=8.1 Hz, 1H), 7.43–7.39 (m, 3H), 7.32
(t, J=7.2 Hz, 1H), 6.71 (s, 1H), 3.85 (s, 3H), 2.58 ppm (s, 3H); 13C NMR
(100 MHz, CDCl3): d=141.6, 138.2, 137.6, 129.9, 129.2, 129.1, 127.9,
121.4, 120.3, 119.7, 109.5, 101.3, 34.0, 21.2 ppm.
1-Methyl-2-phenyl-1H-indole (3b)[4b]
Colorless solid; 1H NMR (400 MHz, CDCl3): d=7.70–7.68 (m, 1H),
7.56–7.50 (m, 4H), 7.45–7.40 (m, 2H), 7.31–7.29 (m, 1H), 7.20–7.18 (m,
1H), 6.62–6.60 (m, 1H), 3.79 ppm (s, 3H); 13C NMR (100 MHz, CDCl3):
d=141.6, 138.3, 132.8, 129.4, 128.5, 127.9, 127.8, 121.6, 120.5, 119.8, 109.6,
101.6, 31.1 ppm.
2-(4-Fluorophenyl)-1-methyl-1H-indole (3k)[4b]
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.68 (d, J=6.8 Hz, 1H),
7.53–7.49 (m, 2H), 7.40 (d, J=8.0 Hz, 1H), 7.30–7.29 (m, 1H), 7.22–7.18
(m, 3H), 6.58 (s, 1H), 3.76 ppm (s, 3H); 13C NMR (100 MHz, CDCl3):
d=162.6 (d, J=246.28 Hz), 140.4, 138.2, 131.0 (d, J=8.1 Hz), 128.9 (d,
J=3.4 Hz), 127.8, 121.7, 120.4, 119.9, 115.5 (d, J=21.4 Hz), 109.6, 101.7,
31.0 ppm.
1-Methyl-2-(m-tolyl)-1H-indole (3c)[4b]
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.67 (d, J=7.8 Hz, 1H),
2-(4-Chlorophenyl)-1-methyl-1H-indole (3l)[4b]
7.41–7.33 (m, 4H), 7.30–7.24 (m, 2H), 7.17 (t, J=7.4 Hz, 1H), 6.58 (s,
1H), 3.78 (s, 3H), 2.47 ppm (s, 3H); 13C NMR (100 MHz, CDCl3): d=
141.7, 138.3, 138.1, 132.7, 130.1, 128.6, 128.3, 128.0, 126.4, 121.5, 120.4,
119.8, 109.5, 101.5, 31.1, 21.5 ppm.
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.68 (d, J=7.8 Hz, 1H),
7.49–7.45 (m, 4H), 7.40 (d, J=8.2 Hz, 1H), 7.30 (t, J=7.6 Hz, 1H), 7.20
(t, J=7.2 Hz, 1H), 6.59 (s, 1H), 3.76 ppm (s, 3H); 13C NMR (100 MHz,
CDCl3): d=140.2, 138.4, 133.9, 131.3, 130.5, 128.7, 127.8, 121.9, 120.5,
120.0, 109.6, 102.0, 31.1 ppm.
1-Methyl-2-(o-tolyl)-1H-indole (3d)[4b]
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.69 (d, J=7.8 Hz, 1H),
7.41–7.37 (m, 3H), 7.35–7.29 (m, 3H), 7.19 (t, J=7.4 Hz, 1H), 6.48 (s,
1H), 3.55 (s, 3H), 2.45 ppm (s, 3H); 13C NMR (100 MHz, CDCl3): d=
140.5, 138.0, 137.3, 132.5, 131.1, 130.0, 128.6, 128.0, 125.5, 121.2, 120.3,
119.6, 109.4, 101.5, 30.3, 20.0 ppm.
1,5-Dimethyl-2-(p-tolyl)-1H-indole (3m)
Colorless solid; 1H NMR (400 MHz, CDCl3): d=7.50–7.47 (m, 3H),
7.36–7.31 (m, 3H), 7.15 (d, J=8.2 Hz, 1H), 3.54 (s, 1H), 3.78 (s, 3H),
2.56 (s, 3H), 2.50 ppm (s, 3H); 13C NMR (100 MHz, CDCl3): d=141.6,
137.6, 136.7, 130.0, 129.2, 129.1, 128.9, 128.2, 123.0, 120.0, 109.2, 100.7,
31.1, 21.4, 21.2 ppm; HRMS (ESI): m/z calcd for C17H18N: 236.1439
[M+H]+; found: 236.1435.
2-(4-Ethylphenyl)-1-methyl-1H-indole (3e)[15]
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.76 (d, J=7.4 Hz, 1H),
7.55 (d, J=6.4 Hz, 2H), 7.46 (d, J=8.0 Hz, 1H), 7.42–7.35 (m, 3H), 7.29–
7.25 (m, 1H), 6.67 (s, 1H), 3.84 (s, 3H), 2.84 (q, J=7.4 Hz, 2H), 1.43–
1.40 ppm (m, 3H); 13C NMR (100 MHz, CDCl3): d=144.0, 141.6, 138.2,
130.1, 129.3, 128.0, 127.9, 121.5, 120.3, 119.7, 109.5, 101.3, 31.1, 28.6,
15.5 ppm.
1,7-Dimethyl-2-(p-tolyl)-1H-indole (3n)[9b]
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.50 (d, J=7.7 Hz, 1H),
7.40 (d, J=7.8 Hz, 2H), 7.30 (d, J=7.8 Hz, 2H), 7.02 (t, J=7.4 Hz, 1H),
6.95 (d, J=6.8 Hz, 1H), 6.51 (s, 1H), 3.95 (s, 3H), 2.84 (s, 3H), 2.45 ppm
(s, 3H); 13C NMR (100 MHz, CDCl3): d=142.8, 137.7, 137.5, 130.1, 129.5,
129.1, 128.9, 124.5, 121.4, 120.0, 118.5, 102.1, 34.4, 21.3, 20.2 ppm.
2-(4-Isopropylphenyl)-1-methyl-1H-indole (3 f)
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.69 (d, J=7.8 Hz, 1H),
5-Methoxy-1-methyl-2-(p-tolyl)-1H-indole (3o)[9b]
7.50 (d, J=8.0 Hz, 2H), 7.42–7.37 (m, 3H), 7.30 (t, J=7.6 Hz, 1H), 7.20
(t, J=7.4 Hz, 1H), 6.60 (s, 1H), 3.80 (s, 3H), 3.09–2.98 (m, 1H),
1.37 ppm (d, J=6.9 Hz, 6H); 13C NMR (100 MHz, CDCl3): d=148.6,
141.7, 138.3, 130.3, 129.3, 128.0, 126.5, 121.5, 120.3, 119.7, 109.5, 101.3,
33.9, 31.1, 23.9 ppm; HRMS (ESI): m/z calcd for C18H20N: 250.1596
[M+H]+; found: 250.1593.
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.44 (d, J=7.8 Hz, 2H),
7.32–7.27 (m, 3H), 7.15 (s, 1H), 6.95 (d, J=8.8 Hz, 1H), 6.51 (s, 1H),
3.91 (s, 3H), 3.75 (s, 3H), 2.47 ppm (s, 3H); 13C NMR (100 MHz, CDCl3):
d=154.3, 142.2, 137.6, 133.7, 130.0,129.2, 129.1, 128.2, 111.6, 110.2, 102.1,
100.9, 55.9, 31.1, 21.2 ppm.
2-(3,4-Dimethylphenyl)-1-methyl-1H-indole (3g)
5-Methoxy-1-methyl-2-phenyl-1H-indole (3p)[4b]
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.72 (d, J=7.8 Hz, 1H),
Colorless solid; 1H NMR (400 MHz, CDCl3): d=7.57–7.50 (m, 4H),
7.46–7.43 (m, 1H), 7.31 (d, J=8.8 Hz, 1H), 7.17 (d, J=1.9 Hz, 1H), 6.99–
6.96 (m, 1H), 6.55 (s, 1H), 3.92 (s, 3H), 3.76 ppm (s, 3H); 13C NMR
(100 MHz, CDCl3): d=154.34, 142.08, 133.78, 132.86, 129.23, 128.43,
128.22, 127.74, 111.86, 110.29, 102.17, 101.26, 55.88, 31.22 ppm.
7.43 (d, J=8.2 Hz, 1H), 7.39 (s, 1H), 7.34–7.30 (m, 3H), 7.23 (t, J=
7.4 Hz, 1H), 6.62 (s, 1H), 3.81 (s, 3H), 2.42 ppm (s, 6H); 13C NMR
(100 MHz, CDCl3): d=141.7, 138.2, 136.7, 136.4, 130.6, 130.3, 129.7,
128.0, 126.7, 121.4, 120.3, 119.7, 109.5, 101.2, 31.0, 19.8, 19.5 ppm; HRMS
(ESI): m/z calcd for C17H18N [M+H]+: 236.1439; found: 236.1436.
5-Fluoro-1-methyl-2-(p-tolyl)-1H-indole (3q)
2-(3,5-Dimethylphenyl)-1-methyl-1H-indole (3h)[4b]
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.42 (d, J=7.9 Hz, 2H),
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.73 (d, J=7.8 Hz, 1H),
7.32–7.27 (m, 4H), 7.03–6.98 (m, 1H), 6.51 (s, 1H), 3.74 (s, 3H),
2.46 ppm (s, 3H); 13C NMR (100 MHz, CDCl3): d=158.1 (d, J=
232.66 Hz), 143.2, 138.0, 134.9, 129.6, 129.2 (d, J=3.87 Hz), 128.1 (d, J=
10.09 Hz), 100.1 (d, J=9.71 Hz), 109.8, 109.5, 105.1 (d, J=23.29 Hz),
101.2 (d, J=4.61 Hz), 31.3, 21.3 ppm; HRMS (ESI): m/z calcd for
C16H15FN: 236.1439 [M+H]+; found: 236.1435.
7.44 (d, J=8.2 Hz, 1H), 7.34 (t, J=7.3 Hz, 1H), 7.27–7.23 (m, 3H), 7.14
(s, 1H), 6.64 (s, 1H), 3.82 (s, 3H), 2.49 ppm (s, 6H); 13C NMR (100 MHz,
CDCl3): d=141.8, 138.3, 138.0, 132.7, 129.5, 128.0, 127.2, 121.4, 120.4,
119.7, 109.5, 101.4, 31.1, 21.3 ppm.
2-(4-Methoxyphenyl)-1-methyl-1H-indole (3i)[4b]
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.67 (d, J=7.7 Hz, 1H),
7.48 (d, J=8.2 Hz, 2H), 7.39 (d, J=8.1 Hz, 1H), 7.30–7.26 (m, 1H), 7.18
4
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Lei Wang et al.
6-Fluoro-1-methyl-2-(p-tolyl)-1H-indole (3r)[9b]
1,3-Dimethyl-2-(p-tolyl)-1H-indole (3z)[9b]
1
Colorless solid; 1H NMR (400 MHz, CDCl3): d=7.60–7.54 (m, 1H), 7.44
(d, J=7.6 Hz, 2H), 7.33 (d, J=7.6 Hz, 2H), 7.08 (d, J=9.9 Hz, 1H), 6.96
(t, J=9.1 Hz, 1H), 6.56 (s, 1H), 3.73 (s, 3H), 2.49 ppm (s, 3H); 13C NMR
(100 MHz, CDCl3): d=159.6 (d, J=235.85 Hz), 142.1 (d, J=3.77 Hz),
138.3 (d, J=15.49 Hz), 137.8, 129.6, 129.2, 129.1, 124.3, 121.0 (d, J=
9.94 Hz), 108.4 (d, J=24.23 Hz), 101.2, 96.0 (d, J=26.02 Hz), 31.2,
21.2 ppm.
Colorless solid; H NMR (400 MHz, CDCl3): d=7.71 (d, J=7.8 Hz, 1H),
7.43–7.39 (m, 5H), 7.35 (t, J=7.5 Hz, 1H), 7.28–7.24 (m, 1H), 3.69 (s,
3H), 2.54 (s, 3H), 2.39 ppm (s, 3H); 13C NMR (100 MHz, CDCl3): d=
137.7, 137.5, 137.1, 130.5, 129.1, 129.0, 128.4, 121.5, 119.0, 118.7, 109.1,
108.2, 30.8, 21.3, 9.5 ppm.
1-Ethyl-3-methyl-2-(p-tolyl)-1H-indole (3aa)
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.67 (d, J=7.8 Hz, 1H),
5-Chloro-1-methyl-2-(p-tolyl)-1H-indole (3s)
7.43 (d, J=8.1 Hz, 1H), 7.36 (s, 4H), 7.31 (t, J=7.8 Hz, 1H), 7.22 (t, J=
7.4 Hz, 1H), 4.14 (q, J=7.1 Hz, 2H), 2.51 (s, 3H), 2.32 (s, 3H), 1.28 ppm
(t, J=7.1 Hz, 3H); 13C NMR (100 MHz, CDCl3): d=137.6, 137.2, 135.9,
130.4, 129.4, 129.1, 128.7, 121.4, 118.9, 118.8, 109.4, 108.5, 38.6, 21.3, 15.3,
9.2 ppm; HRMS (ESI): m/z calcd for C18H20N: 250.1596 [M+H]+; found:
250.1598.
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.60 (s, 1H), 7.41 (d, J=
7.8 Hz, 2H), 7.32–7.29 (m, 3H), 7.20 (d, J=8.6 Hz, 1H), 6.49 (s, 1H),
3.74 (s, 3H), 2.45 ppm (s, 3H); 13C NMR (100 MHz, CDCl3): d=142.9,
138.1, 136.6, 129.4, 129.3, 129.2, 128.9, 125.4, 121.6, 119.6, 110.5, 100.8,
31.2, 21.3 ppm; HRMS (ESI): m/z calcd for C16H15ClN: 256.0893
[M+H]+; found: 256.0891.
1-Butyl-3-methyl-2-(p-tolyl)-1H-indole (3ab)
5-Bromo-1-methyl-2-(p-tolyl)-1H-indole (3t)[9b]
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.65 (d, J=7.8 Hz, 1H),
7.41 (d, J=8.1 Hz, 1H), 7.34 (s, 4H), 7.30–7.27 (m, 1H), 7.20 (t, J=
7.4 Hz, 1H), 4.08 (t, J=7.4 Hz, 2H), 2.50 (s, 3H), 2.30 (s, 3H), 1.68–1.61
(m, 2H), 1.25–1.15 (m, 2H), 0.83 ppm (t, J=7.3 Hz, 3H); 13C NMR
(100 MHz, CDCl3): d=137.5, 137.5, 136.2, 130.4, 129.4, 129.0, 128.5,
121.3, 118.8, 118.7, 109.6, 108.4, 43.6, 32.1, 21.3, 20.0, 13.7, 9.3 ppm;
HRMS (ESI): m/z calcd for C20H24N: 278.1909 [M+H]+; found:
278.1910.
Colorless solid; 1H NMR (400 MHz, CDCl3): d=7.77–7.76 (m, 1H), 7.41
(d, J=7.9 Hz, 2H), 7.34–7.30 (m, 3H), 7.23 (d, J=8.7 Hz, 1H), 6.49 (s,
1H), 3.73 (s, 3H), 2.46 ppm (s, 3H); 13C NMR (100 MHz, CDCl3): d=
142.8, 138.0, 136.9, 129.6, 129.3, 129.3, 129.2, 124.2, 122.7, 112.9, 110.9,
100.7, 31.2, 21.3 ppm.
Methyl 2-(4-methoxyphenyl)-1-methyl-1H-indole-4-carboxylate (3u)
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.55 (d, J=7.2 Hz, 1H),
7.49 (d, J=8.2 Hz, 1H), 7.30–7.25 (m, 3H), 7.11 (s, 1H), 6.94 (d, J=
8.2 Hz, 2H), 3.83 (s, 6H), 3.26 ppm (s, 3H); 13C NMR (100 MHz,
CDCl3): d=169.4, 157.9, 137.7, 129.45, 129.40, 129.3, 124.7, 123.6, 121.8,
121.0, 117.0, 113.5, 112.8, 55.3, 51.3, 32.9 ppm; HRMS (ESI): m/z calcd
for C18H18NO3: 296.1287 [M+H]+; found: 296.1284.
Acknowledgements
This work was financially supported by the National Science Foundation
of China (grant nos. 21372095, 21172092).
1-Ethyl-2-(p-tolyl)-1H-indole (3v)[9b]
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.68 (d, J=7.8 Hz, 1H),
7.45–7.43 (m, 3H), 7.32 (d, J=7.8 Hz, 2H), 7.29–7.25 (m, 1H), 7.18 (t,
J=7.4 Hz, 1H), 6.55 (s, 1H), 4.23 (q, J=7.2 Hz, 2H), 2.47 (s, 3H),
1.36 ppm (t, J=7.2 Hz, 3H); 13C NMR (100 MHz, CDCl3): d=141.1,
137.8, 137.0, 130.2, 129.2, 129.1, 128.3, 121.3, 120.5, 119.7, 109.8, 101.7,
38.7, 21.3, 15.4 ppm.
[1] a) R. H. Thomson, The Chemistry of Natural Products, Blackie, Son,
Glasgow, 1985; b) K. G. B. Torssell, Natural Product Chemistry,
Wiley, Chichester, 1983; c) K. Yamamura, S. Ono, H. Ogoshi, H.
Masuda, Y. Kuroda, Synlett 1989, 18–19; d) I. J. Ninomiya, Nat.
Prod. 1992, 55, 541–546; e) R. J. Sundberg, Indoles, Academic Press,
San Diego, CA, 1996; f) J. Roncali, Chem. Rev. 1992, 92, 711–738;
g) N. K. Garg, R. Sarpong, B. M. Stolz, J. Am. Chem. Soc. 2002, 124,
13179–13184; h) S. Cacchi, G. Fabrizi, Chem. Rev. 2005, 105, 2873–
2920; i) M. Somei, F. Yamada, Nat. Prod. Rep. 2005, 22, 73–103.
[2] a) S. S. Labadie, E. Teng, J. Org. Chem. 1994, 59, 4250–4254; b) E.
Vedejs, D. A. Barda, Org. Lett. 2000, 2, 1033–1035; c) B. Chauder,
A. Larkin, V. Snieckus, Org. Lett. 2002, 4, 815–817; d) X. Cai, V.
Snieckus, Org. Lett. 2004, 6, 2293–2295; e) I. Bennacef, C. N. Haile,
A. Schmidt, A. O. Koren, J. P. Seibyl, J. K. Staley, F. Bois, R. M.
Baldwin, G. Tamagnan, Bioorg. Med. Chem. 2006, 14, 7582–7591;
f) R. Dandu, M. Tao, K. A. Josef, E. R. Bacon, R. L. Hudkins, J.
Heterocycl. Chem. 2007, 44, 437–440; g) Y. B. Liu, G. W. Gribble,
Tetrahedron Lett. 2000, 41, 8717–8721; h) C. A. Merlic, Y. You,
D. M. McInnes, A. L. Zechman, M. M. Miller, Q. Deng, Tetrahedron
2001, 57, 5199–5212; i) C. G. Hartung, A. Fecher, B. Chapell, V.
Snieckus, Org. Lett. 2003, 5, 1899–1902; j) J. Joucla, L. Djakovitch,
Adv. Synth. Catal. 2009, 351, 673–714.
[3] a) B. S. Lane, M. A. Brown, D. Sames, J. Am. Chem. Soc. 2005, 127,
8050–8057; b) E. T. Nadres, A. Lazareva, O. Daugulis, J. Org.
Chem. 2011, 76, 471–483; c) C. Bressy, D. Alberico, M. Lautens, J.
Am. Chem. Soc. 2005, 127, 13148–13149; d) B. S. Lane, D. Sames,
Org. Lett. 2004, 6, 2897–2990; e) X. Wang, B. S. Lane, D. Sames, J.
Am. Chem. Soc. 2005, 127, 4996–4997; f) F. Bellina, S. Cauteruccio,
R. Rossi, Eur. J. Org. Chem. 2006, 1379–1382; g) B. B. Tourꢃ, B. S.
Lane, D. Sames, Org. Lett. 2006, 8, 1979–1982; h) X. Wang, D. V.
Gribkov, D. Sames, J. Org. Chem. 2007, 72, 1476–1479; i) Z. Zhang,
Z. Hu, Z. Yu, P. Lei, H. Chi, Y. Wang, R. He, Tetrahedron Lett.
2007, 48, 2415–2419; j) F. Bellina, C. Calandri, S. Cauteruccio, R.
1-Propyl-2-(p-tolyl)-1H-indole (3w)
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.70 (d, J=7.8 Hz, 1H),
7.46–7.44 (m, 3H), 7.35–7.29 (m, 3H), 7.20 (t, J=7.3 Hz, 1H), 6.57 (s,
1H), 4.17 (t, J=7.8 Hz, 2H), 2.50 (s, 3H), 1.85–1.75 (m, 2H), 0.85 ppm
(t, J=7.3 Hz, 3H); 13C NMR (100 MHz, CDCl3): d=141.6, 137.69, 137.3,
130.4, 129.3, 129.1,128.2, 121.3, 120.4, 119.6, 110.0, 101.7, 45.5, 23.3, 21.3,
11.3 ppm; HRMS (ESI): m/z calcd for C18H20N: 250.1596 [M+H]+;
found: 250.1592.
1-Butyl-2-(p-tolyl)-1H-indole (3x)
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.73 (d, J=7.7 Hz, 1H),
7.49–7.46 (m, 3H), 7.37–7.30 (m, 3H), 7.23 (t, J=7.3 Hz, 1H), 6.59 (s,
1H), 4.23 (t, J=7.4 Hz, 2H), 2.52 (s, 3H), 1.82–1.74 (m, 2H), 1.33–1.24
(m, 2H), 0.91 ppm (t, J=7.4 Hz, 3H); 13C NMR (100 MHz, CDCl3): d=
141.4, 137.7, 137.3, 130.3, 129.3, 129.1, 128.2, 121.2, 120.4, 119.6, 109.9,
101.7, 43.7, 32.1, 21.3, 20.0, 13.6 ppm; HRMS (ESI): m/z calcd for
C19H22N: 264.1752 [M+H]+; found: 264.1749.
1-Benzyl-2-(p-tolyl)-1H-indole (3y)
1
Colorless solid; H NMR (400 MHz, CDCl3): d=7.52 (d, J=4.8 Hz, 1H),
7.43 (d, J=7.6 Hz, 2H), 7.38–7.32 (m, 3H), 7.29–7.24 (m, 5H), 7.13 (d,
J=7.1 Hz, 2H), 6.73 (s, 1H), 5.44 (s, 2H), 2.47 ppm (s, 3H); 13C NMR
(100 MHz, CDCl3): d=141.9, 138.3, 137.9, 137.9, 129.7, 129.3, 129.1,
128.7, 128.3, 127.1, 125.9, 121.7, 120.4, 120.1, 110.5, 101.9, 47.6, 21.2 ppm;
HRMS (ESI): m/z calcd for C22H20N: 298.1596 [M+H]+; found:
298.1598.
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Rossi, Tetrahedron 2007, 63, 1970–1980; k) F. Bellina, F. Benelli, R.
Rossi, J. Org. Chem. 2008, 73, 5529–5535; l) N. Lebrasseur, I. Larro-
sa, J. Am. Chem. Soc. 2008, 130, 2926–2927; m) N. S. Nandurkar,
M. J. Bhanushali, M. D. Bhor, B. M. Bhanage, Tetrahedron Lett.
2008, 49, 1045–1048; n) G. Cusati, L. Djakovitch, Tetrahedron Lett.
2008, 49, 2499–2502; o) J. Roger, H. Doucet, Adv. Synth. Catal.
2009, 351, 1977–1990; p) B. Liꢃgault, I. Petrov, S. I. Gorelsky, K.
Fagnou, J. Org. Chem. 2010, 75, 1047–1060; q) F. Shibahara, E. Ya-
maguchi, T. Murai, Chem. Commun. 2010, 46, 2471–2473; r) L.
Wang, W. B. Yi, C. Cai, Chem. Commun. 2011, 47, 806–808; s) S.
Islam, I. Larrosa, Chem. Eur. J. 2013, 19, 15093–15096; t) H. Dong,
C. Limberakis, S. Liras, D. Price, K. James, Chem. Commun. 2012,
48, 11644–11646; u) G.-P. Lu, C. Cai, Synlett 2012, 2992–2996; v) L.
Joucla, N. Batail, L. Djakovitch, Adv. Synth. Catal. 2010, 352, 2929–
2936; w) Y. Akita, A. Inoue, K. Yamamoto, A. Ohta, T. Kurihara,
M. Shimizu, Heterocycles 1985, 23, 2327–2333; x) A. F. P. Biajoli,
E. T. Penha, C. R. D. Correia, RSC Adv. 2012, 2, 11930–11935.
[4] a) S. Kirchberg, R. Frçhlich, A. S. Studer, Angew. Chem. Int. Ed.
2009, 48, 4235–4238; Angew. Chem. 2009, 121, 4299–4302; b) S.-D.
Yang, C.-L. Sun, Z. Fang, B.-J. Li, Y. Li, Z.-J. Shi, Angew. Chem. Int.
Ed. 2008, 47, 1473–1476; Angew. Chem. 2008, 120, 1495–1498; c) Y.
Huang, T. Ma, P. Huang, D. Wu, Z. Lin, R. Cao, ChemCatChem
2013, 5, 1877–1883; d) J. Zhao, Y. Zhang, K. Cheng, J. Org. Chem.
2008, 73, 7428–7431.
4050–4053; d) Z. Liang, J. Zhao, Y. Zhang, J. Org. Chem. 2010, 75,
170–177; e) A. Garcꢄa-Rubia, B. Urones, R. Gꢅmez Arrayꢆs, J. C.
Carretero, Chem. Eur. J. 2010, 16, 9676–9685; f) D. G. Pintori, M. F.
Greaney, J. Am. Chem. Soc. 2011, 133, 1209–1211; g) S. Potavathri,
K. C. Pereira, S. I. Gorelsky, A. Pike, A. P. LeBris, B. DeBoef, J.
Am. Chem. Soc. 2010, 132, 14676–14681; h) T. Itahara, T. Sakaki-
bara, Synthesis 1978, 607–608; i) T. Itahara, Synthesis 1979, 151–
152; j) T. A. Dwight, N. R. Rue, D. Charyk, R. Josselyn, B. DeBoef,
Org. Lett. 2007, 9, 3137–3139.
[9] a) T. Miao, P. Li, G.-W. Wang, L. Wang, Chem. Asian J. 2013, 8,
3185–3190; b) M. Wu, J. Luo, F. Xiao, S. Zhang, G.-J. Deng, H.-A.
Luo, Adv. Synth. Catal. 2012, 354, 335–340.
[10] M. Dçbele, S. Vanderheiden, N. Jung, S. Brꢀse, Angew. Chem. Int.
Ed. 2010, 49, 5986–5988; Angew. Chem. 2010, 122, 6122–6125.
[11] a) D. B. Kimball, M. M. Haley, Angew. Chem. Int. Ed. 2002, 41,
3338–3351; Angew. Chem. 2002, 114, 3484–3498; b) C. Zhu, M,
Yamane, Org. Lett. 2012, 14, 4560–4563; c) A. Hafner, S. Brꢀse,
Adv. Synth. Catal. 2013, 355, 996–1000; d) C.-Y. Liu, P. Knochel,
Org. Lett. 2005, 7, 2543–2546; e) C.-Y. Liu, P. Knochel, J. Org.
Chem. 2007, 72, 7106–7115; f) J. Zhou, W. Yang, B. Wang, H. Ren,
Angew. Chem. Int. Ed. 2012, 51, 12293–12297; Angew. Chem. 2012,
124, 12459–12463.
[12] a) S. Bhattacharya, S. Majee, R. Mukherjee, S. Sengupta, Synth.
Commun. 1995, 25, 651–657; b) S. Sengupta, S. K. Sadhukkan, Tetra-
hedron Lett. 1998, 39, 715–718; c) S. Sengupta, S. K. Sadhukkan,
Org. Synth. 2002, 79, 52–56.
[13] S. Brꢀse, M. Schroen, Angew. Chem. Int. Ed. 1999, 38, 1071–1073;
Angew. Chem. 1999, 111, 1139–1142.
[5] a) N. R. Deprez, D. Kalyani, A. Krause, M. S. Sanford, J. Am.
Chem. Soc. 2006, 128, 4972–4973; b) R. J. Phipps, N. P. Grimster,
M. J. Gaunt, J. Am. Chem. Soc. 2008, 130, 8172–8174.
[6] Z.-J. Liang, B.-B. Yao, Y.-H. Zhang, Org. Lett. 2010, 12, 3185–3187.
[7] a) J. Cornella, P. F. Lu, I. Larrosa, Org. Lett. 2009, 11, 5506–5509;
b) J. Zhou, P. Hu, M. Zhang, S. Huang, M. Wang, W.-P. Su, Chem.
Eur. J. 2010, 16, 5876–5881.
[14] a) T. Saeki, E.-C. Son, K. Tamao, Org. Lett. 2004, 6, 617–619; b) T.
Saeki, T. Matsunaga, E.-C. Son, K. Tamao, Adv. Synth. Catal. 2004,
346, 1689–1692.
[8] a) D. R. Stuart, K. Fagnou, Science 2007, 316, 1172–1175; b) D. R.
Stuart, E. Villemure, K. Fagnou, J. Am. Chem. Soc. 2007, 129,
12072–12073; c) S. Potavathri, A. S. Dumas, T. A. Dwight, G. R.
Naumiec, J. M. Hammann, B. DeBoef, Tetrahedron Lett. 2008, 49,
[15] M. F. Ibad, D. S. Zinad, M. Hussain, A. Ali, A. Villinger, P. Langer,
Tetrahedron 2013, 69, 7492–7504.
Received: March 22, 2014
Published online: && &&, 0000
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FULL PAPER
ꢀ
C H Functionalization
Can Liu, Tao Miao, Lei Zhang,
Pinhua Li, Yicheng Zhang,
Lei Wang*
&&&& — &&&&
Palladium-Catalyzed Direct C2 Aryla-
tion of N-Substituted Indoles with 1-
Aryltriazenes
Seeing to C2: An efficient Pd-cata-
lyzed C2 arylation of N-substituted
indoles with 1-aryltriazenes for the
synthesis of 2-arylindoles has been
developed. In the presence of
N-substituted indoles reacted with 1-
aryltriazenes in N,N-dimethylaceta-
mide to afford the corresponding aryl–
indole-type products in good to excel-
lent yields.
BF3·OEt2 and palladium(II) acetate,
7
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These are not the final page numbers! ÞÞ