Iridium-Catalyzed Vinylation of Carbazole Derivatives with Vinyl Acetate

Article abstract of DOI:10.1055/s-0036-1588927

We report a practical method for the synthesis of vinylcarbazoles via iridium-catalyzed vinylation of carbazoles with vinyl acetate as the vinyl source. This simple and efficient reaction using an iridium catalyst provides a convenient method for producing monomers for the synthesis of poly(N-vinylcarbazole)s, which are used in electroluminescent devices.

Full text of DOI:10.1055/s-0036-1588927

SYNLETT
0
9
3
6
-
5
2
1
4
1
4
3
7
-
2
0
9
6
© Georg Thieme Verlag Stuttgart · New York
2017, 28, A–E
letter
A
J. Kimura et al.
Letter
Synlett
Iridium-Catalyzed Vinylation of Carbazole Derivatives with Vinyl
Acetate
Jungo Kimura
Seiya Nakamichi
Shinji Ogawa
H
N
N
cat.[IrCl(cod)]2
O
+
Yasushi Obora*
Na2CO3
toluene
100 °C
R
R
O
R
R
Department of Chemistry and Materials Engineering, Faculty of
Chemistry, Materials and Bioengineering, Kansai University,
Suita, Osaka 564-8680, Japan
R = H, Cl, Br, t-Bu
yield 60–94%
vinyl acetate
Ir-catalyzed vinylation of carbazole
obora@kansai-u.ac.jp
Easily accesible vinyl acetate as vinyl source
One-step reaction
Received: 02.11.2016
Accepted after revision: 02.12.2016
Published online: 10.01.2017
reaction of carbazoles and pressurized acetylene in the
presence of a base.5 In addition, a two-step transition-met-
al-free synthesis of vinylcarbazoles was recently reported.6
DOI: 10.1055/s-0036-1588927; Art ID: st-2016-u0742-l
Abstract We report a practical method for the synthesis of vinylcarba-
zoles via iridium-catalyzed vinylation of carbazoles with vinyl acetate as
the vinyl source. This simple and efficient reaction using an iridium cat-
alyst provides a convenient method for producing monomers for the
synthesis of poly(N-vinylcarbazole)s, which are used in electrolumines-
cent devices.
Voskoboynikov (a)
Miura (b)
cat. Pd(dba)2
+
Br
R
+
cat. Pd(OAc)2
Ag2CO3
+
R
P(tBu)3
carbazole
carbazole
N
Key words vinylation, N-vinylcarbazole, iridium catalyst, vinyl acetate,
carbazole
Alami (d)
Su (c)
cat. Pd2(dba)3⋅CHCl3
cat. Pd(MeCN)2Cl2
CuCl2/O2
N-Vinylcarbazole derivatives are used as monomers for
the synthesis of poly(N-vinylcarbazole)s, which are widely
used in organic electroluminescent devices (OEL) and pho-
torefractive materials.1 Azole frameworks containing carba-
zoles are also key building blocks in organic chemistry and
medicinal chemistry.2 N-Vinylcarbazoles, which have both
conjugated portions and vinyl groups, are useful com-
pounds, and methods for their synthesis are receiving much
attention.
Traditionally, vinylcarbazole has been synthesized using
the Clemo–Perkin method, that is, base-mediated dehalo-
genation of N-2-chloroethylcarbazole obtained by chlorina-
tion of carbazole with 2-chloroethyl-p-toluenesulfonate.3
This method requires an excess of 2-chloroethyl-p-toluene-
sulfonate and long reaction times. Transition-metal-cata-
lyzed cross-coupling reactions of azole derivatives and vinyl
halides are also well-known strategies for synthesizing vi-
nylazoles, including vinylcarbazoles (Scheme 1, a).4 Howev-
er, these methods are generally multistep and afford stoi-
chiometric amounts of halogen salts as byproducts. Vinyl-
carbazoles have been synthesized industrially by the
PhI, NaOtBu
NHTs
N
R
+
R
carbazole
carbazole
+
R
R
Scheme 1 Conceptual overview of previously reported transition-
metal-catalyzed carbazole vinylations
Alternative reactions for the synthesis of vinylazole de-
rivatives using transition-metal catalysts have been investi-
gated.7–10 In particular, the dehydrogenative coupling of
azole derivatives with alkenyl compounds instead of vinyl
halides has been actively investigated. Miura and co-workers
described a palladium-mediated aza-Wacker reaction of
carbazoles and alkenes with Ag2CO3 as the oxidant (Scheme
1, b).11 Su and co-workers reported a versatile palladium-
catalyzed direct alkenylation of indoles in the presence of
CuCl2 or other additives, with oxygen gas as the oxidant
(Scheme 1, c).12 Alami and co-workers developed ligand-
free palladium-catalyzed oxidative coupling reactions of N-
tosylhydrazones and indole derivatives (Scheme 1, d).13 The
synthesis of N-substituted π-conjugated carbazoles such as
N-vinylarylcarbazoles have also been reported.14
© Georg Thieme Verlag Stuttgart · New York — Synlett 2017, 28, A–E

B
J. Kimura et al.
Letter
Synlett
Carbazole is easily obtained by coal-tar distillation.1a
Several methods for carbazole preparation have been re-
ported.15 Carbazoles can be prepared by intramolecular C–
H bond amination reactions of substituted N,N-biaryl
amines,16 dehydrogenative C–C bond formation of N,N-bi-
aryl amines,17 and one-pot synthesis by sequential C–C/C–N
bond formation.18 Vinylcarbazole synthesis using a vinyl
halide as the vinyl source is a multistep process.2c,4 Reaction
systems for vinylcarbazole synthesis that are simple, safe,
manageable, and use cheap and readily available substrates
are needed.
Vinyl acetate is an attractive vinyl source because it is
an inexpensive, easy-to-handle, halogen-free feedstock of
low toxicity. Vinyl acetate has therefore been widely used
for the synthesis of styrene derivatives.19 Recently, vinyla-
tion of sulfonamides with vinyl acetate was achieved using
palladium/carbene catalytic systems;20 however, the study
did not cover carbazole derivatives. Reports of transition-
metal-catalyzed N-vinylcarbazole synthesis are rare. Palla-
dium and copper co-catalyzed vinylation of carbazoles with
vinyl acetate as the vinyl source has been reported.21 The
use of Pd(OAc)2 and Cu(OAc)2 as catalysts gave N-vinylcar-
bazoles in moderate yields.
Alternatively, iridium complexes are widely used in or-
ganic synthesis because of their high catalytic activities.22
Our group has reported a wide range of organic reactions
catalyzed by iridium complexes.23–25 We synthesized vinyl
ethers via iridium-catalyzed vinylation of alcohols with vi-
nyl acetate as the vinyl source.26 In light of recent develop-
ment in iridium-catalyzed reaction, further investigation
on new vinylations using vinyl acetate is highly desirable.
Here, we report a practical method for vinylcarbazole syn-
thesis via iridium-catalyzed vinylation of carbazoles with
vinyl acetate as the vinyl source. This simple vinylation
method using vinyl acetate did not produce halogen salts as
wastes.
Table 1 Iridium-Catalyzed Vinylation of Carbazole (1a) with Vinyl Ace-
tate (2)a
H
N
[Ir] (cat.)
base
O
N
+
toluene
100 °C, 15 h
O
1a
2
3a
Entry
Ir catalyst
[IrCl(cod)]2
Base
Yield (%)b
1
2
Na2CO3
Na2CO3
Na2CO3
Na2CO3
Na2CO3
Na2CO3
Na2CO3
MeCO2Na
Cs2CO3
KOt-Bu
Na2CO3
none
96 (94)c
86
[Ir(cod)2]BF4
[Ir(OH)(cod)]2
[IrCl(coe)2]2
IrCl3·3H2O
[Cp*IrCl2]2
[RhCl(cod)]2
[IrCl(cod)]2
[IrCl(cod)]2
[IrCl(cod)]2
[IrCl(cod)]2
[IrCl(cod)]2
none
3
47
4
24
5
2
6
n.d.d
44
7
8
86
9
31
10
11f
12
13
14g
8e
54
2
Na2CO3
Na2CO3
n.d.d
61
[IrCl(cod)]2
a Conditions: 1a (1 mmol) was allowed to react 2 with (5 mmol) in the pres-
ence of Ir catalyst (0.01 mmol) and base (1.2 mmol) in toluene (1 mL) at
100 °C for 15 h.
b GC yields based on 1a. The isolated yield is given in parentheses.
c Isolated yield.
d Not detected by GC.
e N-Acetylcarbazole was observed.
f Na2CO3 (0.1 mmol) was used.
g 2 (1 mmol) was used.
Cl(cod)]2, which is an analogue of [IrCl(cod)]2, was less ef-
fective than the iridium catalyst (Table 1, entry 7). Na2CO3
was the most appropriate base, and weak bases such as Me-
COONa were also suitable for this reaction (Table 1, entries
1 and 8). When Cs2CO3 or KOt-Bu was used as the base, GC
analysis showed that intractable mixtures were obtained;
N-acetylcarbazole was detected (Table 1, entries 9 and 10).
Excess base was generally necessary to obtain the product
in high yield, but a catalytic amount of Na2CO3 (0.1 mmol)
afforded the product in moderate yield (Table 1, entries 1
and 11). We suggest that the base has two roles, that is, pro-
moting catalyst–ligand exchange and neutralizing acetic ac-
id, which is a byproduct of the reaction. The reaction was
sluggish in the absence of a base (Table 1, entry 12). When
no iridium catalyst was used, the reaction did not progress
because little conversion of the carbazole substrate oc-
curred (Table 1, entry 13). These results indicate that the
iridium catalyst and base both play significant roles in this
reaction. When 1 mmol of vinyl acetate was used, the reac-
tion proceeded, but the yield was low (Table 1, entry 14).
We optimized the reaction conditions using carbazole
(1a) and vinyl acetate (2) as model substrates; the results
are shown in Table 1. We first examined [IrCl(cod)]2 (cod =
1,5-cyclooctadiene) as the catalyst because we previously
reported its use in organic reactions.26 The reaction of 1a (1
mmol) with 2 (5 mmol, 0.46 mL) in the presence of [Ir-
Cl(cod)]2 (0.01 mmol, 1 mol%) as the catalyst and Na2CO3
(1.2 mmol) as a base at 100 °C for 15 hours in toluene gave
N-vinylcarbazole in 96% yield and 94% isolated yield (Table
1, entry 1).
We then investigated the use of other iridium complex-
es. The cationic complex [Ir(cod)2]BF4 also promoted the re-
action and afforded the product in good yield (Table 1, en-
try 2). The product was obtained in moderate yield when
[Ir(OH)(cod)]2 was used instead of [IrCl(cod)]2 (Table 1, en-
try 3). [IrCl(coe)2]2 was less effective under the reaction
conditions used (Table 1, entry 4). IrCl3·H2O and [Cp*IrCl2]2
were inert in the reaction (Table 1, entries 5 and 6). [Rh-
© Georg Thieme Verlag Stuttgart · New York — Synlett 2017, 28, A–E

C
J. Kimura et al.
Letter
Synlett
This suggests that excess vinyl acetate is needed in this re-
action system. Screening showed that toluene was the best
solvent; n-octane was also suitable (84% yield), but 1,4-di-
oxane was less suitable as a solvent for the vinylation reac-
tion (31% yield). The polar solvent N,N-dimethylformamide
gave N-acetylcarbazole instead of N-vinylcarbazole (3a).
The desired vinylation product was obtained in moderate
yield under solvent-free conditions (67% yield). When the
temperature was increased, the yield decreased, probably
because polymerization occurred.
We then investigated the scope of carbazoles that can be
used in this reaction (Table 2).27 It has been reported that
halogen-substituted poly(N-vinylcarbazole)s have different
electronic structures, resulting in different photophysical
properties.28 We therefore initially examined 3,6-dichloro-
carbazole (1b) with a halogen substituent. The vinylation of
3,6-dichlorocarbazole (1b) proceeded smoothly and the
N-vinylated product (3b) was obtained in excellent yield
(Table 2, entry 1). The scaffolds used in carbazole synthesis
are important in studies of the photoconductivity of
poly(N-vinylcarbazole)s because they enable modification
of the polymer properties by introducing other structures
such as long π-conjugated moieties into the carbazole;29
bromo substituents are useful because they can be easily
transformed via metal-catalyzed coupling reactions. 3,6-Di-
bromocarbazole (1c) underwent vinylation without loss of
the bromo substituent, and vinylation of 2,7-dibromocar-
bazole (1d) also proceeded in good yield (Table 2, entries 2
and 3). A carbazole bearing an electron-withdrawing tert-
butyl group was tolerated. The product was a mixture of the
desired vinylcarbazole and the substrate, 3,6-di-tert-butyl-
carbazole (1e); the yield was moderate.
Table 2 Iridium-Catalyzed Reactions of Carbazole Derivatives with Vinyl Acetate (2)a
Entry
Carbazole derivatives
Product
Yield (%)
94
H
N
N
1
1a
3a
H
N
N
2
84
Cl
1b
Cl
Cl
3b
Cl
H
N
N
3
71
61
71
Br
Br
Br
Br
1c
3c
H
N
N
Br
Br
4
Br
Br
1d
3d
H
N
N
5b
tBu
1e
tBu
tBu
3e
tBu
© Georg Thieme Verlag Stuttgart · New York — Synlett 2017, 28, A–E

D
J. Kimura et al.
Letter
Synlett
Table 2 (continued)
Entry
Carbazole derivatives
Product
Yield (%)
60
H
N
N
6
1f
3f
H
N
N
7
n.d.c
n.d.c
1g
3g
H
N
N
8d
1a
3h
a Conditions: Carbazole derivatives (1 mmol) was allowed to react 2 with (5 mmol) in the presence of [IrCl(cod)]2 (0.01 mmol) and base (1.2 mmol) in toluene (1
mL) at 100 °C for 15 h.
b Ir catalyst (0.03 mmol) was used.
c Not detected by GC.
d Isopropenyl acetate (5 mmol) was used.
Next, we examined azole derivatives other than carba-
zoles. The vinylation of 2,3-dimethylindole (1f) gave the
corresponding product 3f in good yield (Table 2, entry 6).
The reactions using 3-methylindole and indole proceeded.
The yield gradually decreased with decreasing number of
methyl groups in the indole. 2,5-Dimethylpyrrole (1g) did
not react with vinyl acetate in this catalytic system (Table 2,
entry 7). Phenoxazine, phenothiazine, diphenylamine, and
morpholine did not give the desired products. These reac-
tion trends can be attributed to the N–H acidity; the pKa
values in DMSO of carbazole, indole, and pyrrole are 19.9,
21.0, and 23.0, respectively.30 However, the use of amides
such as succinimide, phthalimide, and p-toluenesulfon-
amide were totally inactive toward vinylation under these
conditions. Our group reported an iridium-catalyzed reac-
tion with isopropenyl acetate as the vinyl source for car-
bonyl compound synthesis.26 However, the use of isoprope-
nyl acetate did not afford any vinylated product at all under
these conditions (Table 2, entry 8).
The reaction mechanism was not clear, but we think
that the pathways are similar to those previously reported
for vinylation of alcohols.26a First, an iridium–carbazole
species is generated from iridium, the carbazole, and the
base. Vinylcarbazole is formed by vinyl acetate insertion
followed by β-OAc elimination. The iridium–carbazole spe-
cies is regenerated by ligand exchange.
In conclusion, we have developed a simple and efficient
reaction, the iridium-catalyzed vinylation of carbazole de-
rivatives with vinyl acetate, which is a commercially avail-
able and halogen-free vinyl source. The reaction proceeds
in one step and gives the desired product in good yield. This
reaction provides a convenient method for monomer syn-
thesis for poly(N-vinylcarbazole)s.
Further investigations of the detailed reaction mecha-
nism and scope and application of this reaction are current-
ly in progress.
Acknowledgment
This work was supported by a Grant-in-Aid for Scientific Research
(KAKENHI).
Supporting Information
Supporting information for this article is available online at
http://dx.doi.org/10.1055/s-0036-1588927.
S
u
p
p
ortiInfogrmoaitn
S
u
p
p
o
nrtogI
f
rmoaitn
References and Notes
(1) (a) Grazulevicicius, J. V.; Strohriegl, P.; Pielichowski, J.;
Pielichowski, K. Prog. Polym. Sci. 2003, 28, 1297. (b) Hu, B.; Yang,
Z.; Karasz, F. E. J. Appl. Phys. 1994, 76, 2419. (c) Sanetra, J.; Barta,
P.; Niziol, S.; Chrzaszcz, R.; Pielichowski, J. Synth. Met. 1998, 94,
123. (d) Sanetra, J.; Annatys, P.; Chrzaszcz, R.; Pielichowski, J.;
Barta, P.; Niziol, S.; Sahraoui, B. Synth. Met. 1999, 101, 82.
(e) Angiuli, M.; Ciardelli, F.; Colligiani, A.; Greco, F.; Romano, A.;
Ruggeri, G.; Tombari, E. Appl. Opt. 2006, 30, 7928. (f) Kawakami,
T.; Sonoda, N. Appl. Phys. Lett. 1993, 62, 2167. (g) Mizuno, Y.;
Takasu, I.; Uchikoga, S.; Enomoto, S.; Sawabe, T.; Amano, A.;
© Georg Thieme Verlag Stuttgart · New York — Synlett 2017, 28, A–E

E
J. Kimura et al.
Letter
Synlett
Wada, A.; Sugizaki, T.; Yoshida, J.; Ono, T.; Adachi, C. J. Phys.
Chem. C. 2012, 116, 20681.
2009, 74, 3152. (f) Chakrabarty, S.; Chatterjee, I.; Tebben, L.;
Studer, A. Angew. Chem. Int. Ed. 2013, 52, 2968.
(2) (a) Knolker, H.-J.; Reddy, K. R. Chem. Rev. 2002, 102, 4303.
(b) Schmidt, A. W.; Reddy, K. R.; Knolker, H.-J. Chem. Rev. 2012,
112, 3193. (c) Li, H.; Boonnak, N.; Padwa, A. J. Org. Chem. 2011,
76, 9488. (d) Maki, Y.; Mori, H.; Endo, T. Macromolecules 2007,
40, 6119. (e) Oishi, S.; Watanabe, T.; Sawada, J.; Asai, A.; Ohno,
H.; Fujii, N. J. Med. Chem. 2010, 53, 5054. (f) Takeuchi, T.; Oishi,
S.; Watanabe, T.; Ohno, H.; Sawada, J.; Matsuno, K.; Asai, A.;
Asada, N.; Kitaura, K.; Fujii, N. J. Med. Chem. 2011, 54, 4839.
(3) (a) Clemo, G. R.; Perkin, W. H. J. Chem. Soc. 1924, 125, 1804.
(b) Pielichowski, J.; Kyziol, J. J. Polym. Sci. Pol. Lett. 1974, 12, 257.
(c) Pielichowski, J.; Kyziol, J. J. Polym. Sci. Pol. Lett. 1985, 23, 387.
(4) (a) Lebedev, A. Y.; Izmer, V. V.; Kazyul’kin, D. N.; Beletskaya, I.
P.; Voskoboynikov, A. Z. Org. Lett. 2002, 4, 623. (b) Liao, Q.;
Wang, Y.; Zhang, L.; Xi, C. J. Org. Chem. 2009, 74, 6371. (c) Li, H.;
Boonnak, N.; Padwa, A. Tetrahedron Lett. 2011, 52, 2062.
(5) Davidge, H. J. Appl. Chem. 1959, 9, 241.
(19) (a) Yu, J.-Y.; Kuwano, R. Angew. Chem. Int. Ed. 2009, 48, 7217.
(b) Lindh, J.; Savmarker, J.; Nilsson, P.; Sjoberg, P. J. R.; Larhed,
M. Chem. Eur. J. 2009, 15, 4630. (c) Otley, K. D.; Ellman, J. A. Org.
Lett. 2015, 17, 1332. (d) Mei, S.-T.; Jiang, K.; Wang, N.-J.; Shuai,
L.; Yuan, Y.; Wei, Y. Eur. J. Org. Chem. 2015, 6135.
(20) Xu, J.; Fu, Y.; Xiao, B.; Gong, T.; Guo, Q. Tetrahedron Lett. 2010,
51, 5476.
(21) Yonehara, K.; Okuka, S. JP 2010184923, 2010.
(22) (a) Suzuki, T. Chem. Rev. 2011, 111, 1825. (b) Obora, Y. ACS Catal.
2014, 4, 3972. (c) Huang, F.; Liu, Z.; Yu, Z. Angew. Chem. Int. Ed.
2016, 55, 862.
(23) (a) Ogawa, S.; Obora, Y. Chem. Commun. 2014, 50, 2491.
(b) Obora, Y.; Ogawa, S.; Yamamoto, N. J. Org. Chem. 2012, 77,
9429. (c) Obora, Y.; Anno, Y.; Okamoto, R.; Matsu-ura, T.; Ishii,
Y. Angew. Chem. Int. Ed. 2011, 50, 8618. (d) Matsu-ura, T.;
Sakaguchi, S.; Obora, Y. T.; Ishii, Y. J. Org. Chem. 2006, 71, 8308.
(e) Koda, K.; Matsu-ura, T.; Obora, Y. T.; Ishii, Y. Chem. Lett.
2009, 38, 838. (f) Yamamoto, N.; Obora, Y.; Ishii, Y. Chem. Lett.
2009, 38, 1106. (g) Izumi, A.; Obora, Y.; Sakaguchi, S.; Ishii, Y.
Tetrahedron Lett. 2006, 47, 9199. (h) Taguchi, K.; Nakagawa, H.;
Hirabayashi, T.; Sakaguchi, S.; Ishii, Y. J. Am. Chem. Soc. 2004,
126, 72. (i) Morita, M.; Obora, Y.; Ishii, Y. Chem. Commun. 2007,
2850.
(24) (a) Hirabayashi, T.; Sakaguchi, S.; Ishii, Y. Adv. Synth. Catal. 2005,
347, 872. (b) Sakaguchi, S.; Mizuta, T.; Ishii, Y. Org. Lett. 2006,
12, 2459. (c) Obora, Y.; Hatanaka, S.; Ishii, Y. Org. Lett. 2009, 11,
3510. (d) Hatanaka, S.; Obora, Y.; Ishii, Y. Chem. Eur. J. 2010, 16,
1883. (e) Mizuta, T.; Sakaguchi, S.; Ishii, Y. J. Org. Chem. 2005,
70, 2195.
(25) (a) Aramoto, H.; Obora, Y.; Ishii, Y. J. Org. Chem. 2009, 74, 628.
(b) Taguchi, K.; Sakaguchi, S.; Ishii, Y. Tetrahedron Lett. 2005, 46,
4539. (c) Nakagawa, H.; Sakaguchi, S.; Ishii, Y. Chem. Commun.
2003, 502.
(26) (a) Okimoto, Y.; Sakaguchi, S.; Ishii, Y. J. Am. Chem. Soc. 2002,
124, 1590. (b) Obora, Y.; Ishii, Y. Org. Synth. 2012, 89, 307.
(c) Morita, M.; Sakaguchi, S.; Ishii, Y. J. Org. Chem. 2006, 71,
6285. (d) Hirabayashi, T.; Sakaguchi, S.; Ishii, Y. Org. Synth. 2005,
82, 55. (e) Nagasawa, H.; Okimoto, Y.; Sakaguchi, S.; Ishii, Y. Tet-
rahedron Lett. 2003, 44, 103.
(6) Inoue, N.; Yamada, Y. JP 2015101572, 2015.
(7) Ondrus, A. E.; Movassaghi, M. J. Org. Chem. 2005, 70, 8683.
(8) Zhang, Y.; Donahue, J. P.; Li, C.-J. Org. Lett. 2007, 9, 627.
(9) Das, U. K.; Bhattacharjee, M. Chem. Eur. J. 2012, 18, 5180.
(10) Lam, P. Y. S.; Vincent, G.; Bonne, D.; Clark, C. G. Tetrahedron. Lett.
2003, 44, 4927.
(11) Takeda, D.; Hirano, K.; Satoh, T.; Miura, M. Org. Lett. 2013, 15,
1242.
(12) Wu, G.; Su, W. Org. Lett. 2013, 15, 5278.
(13) (a) Roche, M.; Bignon, J.; Brion, J.-D.; Hamze, A.; Alami, M. J. Org.
Chem. 2014, 79, 7583. (b) Roche, M.; Frison, G.; Brion, J.-D.;
Provot, O.; Hamze, A.; Alami, M. J. Org. Chem. 2013, 78, 8485.
(14) (a) Adhikari, R. M.; Shah, B. K.; Palayangoda, S. S.; Neckers, D. C.
Langmuir 2009, 25, 2402. (b) Adhikari, R. M.; Mondal, R.; Shah,
B. K.; Neckers, D. J. Org. Chem. 2007, 72, 4727. (c) Wan, Y.; Yan,
L.; Zhao, Z.; Ma, X.; Guo, Q.; Jia, M.; Lu, P.; Ramous-Ortiz, G.;
Maldonado, J. L.; Rodriguez, M.; Xia, A. J. Phys. Chem. B 2010,
114, 11737. (d) Yang, Z.; Chi, Z.; Yu, T.; Zhang, X.; Chen, M.; Xu,
B.; Liu, S.; Zhang, Y.; Xu, J. J. Mater. Chem. 2009, 19, 5541.
(e) Panthi, K.; Adhikari, R. M.; Kinstle, T. H. J. Phys. Chem. A
2010, 114, 4550.
(15) (a) Knolker, H.-J.; Reddy, K. R. Chem. Rev. 2002, 102, 4303.
(b) Schmidt, A. W.; Reddy, K. R.; Knolker, H.-J. Chem. Rev. 2012,
112, 3193. (c) Knolker, H.-J. Chem. Lett. 2009, 38, 8.
(27) Experimental Procedure of the Reaction of 1d with 2 (Table
2, Entry 4)
(16) (a) Choi, S.; Chatterjee, T.; Choi, W. J.; You, Y.; Cho, E. J. ACS
Catal. 2015, 5, 4796. (b) Suzuki, C.; Hirano, K.; Satoh, T.; Miura,
M. Org. Lett. 2015, 17, 1597. (c) Takamatsu, K.; Hirano, K.; Satoh,
T.; Miura, M. Org. Lett. 2014, 16, 2892. (d) Cho, S. H.; Yoon, J.;
Chang, S. J. Am. Chem. Soc. 2011, 133, 5996. (e) Tsang, W. C. P.;
Zheng, N.; Bucwald, S. L. J. Am. Chem. Soc. 2005, 127, 14560.
(f) Tsang, W. C. P.; Zheng, N.; Buchwald, S. L. J. Am. Chem. Soc.
2005, 127, 14560.
(17) (a) Gensch, T.; Ronnefahrt, M.; Czerwonka, R.; Jager, A.; Kataeva,
O.; Bauer, I.; Knolker, H.-J. Chem. Eur. J. 2012, 18, 770.
(b) Gruner, K. K.; Knolker, H.-J. Org. Biomol. Chem. 2008, 6, 3902.
(c) Forke, R.; Jager, A.; Knolker, H.-J. Org. Biomol. Chem. 2008, 6,
2481. (d) Kumar, V. P.; Gruner, K. K.; Kataeva, O.; Knolker, H.-J.
Angew. Chem. Int. Ed. 2013, 52, 11073. (e) Hesse, R.; Gruner, K.
K.; Kataeva, O.; Schmidt, A. E.; Knolker, H.-J. Chem. Eur. J. 2013,
19, 14098.
A mixture of [IrCl(cod)]2 (6.7 mg, 0.01 mmol), Na2CO3 (127 mg,
1.2 mmol), 1d (325 mg, 1 mmol), and 2 (430 mg, 5 mmol) in
toluene (1 mL) was stirred at 100 °C for 15 h under Ar. The
product 3d was isolated by column chromatography (230–400
mesh silica gel neutralized with 5% Et3N in n-hexane) in 61%
yield (214 mg).
Compound 3d: white solid, mp 101–105 °C. 1H NMR (CDCl3): δ
= 7.79–7.70 (m, 4 H), 7.37–7.34 (m, 2 H), 7.04 (dd, J = 15.6, 9.2
Hz, 1 H), 5.50 (dd, J = 15.6, 0.9 Hz, 1 H), 5.21 (dd, J = 9.2, 0.9 Hz, 1
H). 13C NMR (CDCl3): δ = 140.3 (C), 128.8 (CH), 124.3 (CH), 122.3
(C), 121.4 (CH), 120.3 (C), 113.8 (CH), 105.4 (CH2). IR (KBr):
3400, 3080, 2920, 2850, 1590, 1450, 1320, 1060, 790 cm–1. GC–
MS (EI): m/z (%) = 350 (100) [M] +, 191 (94), 349 (51), 352 (49),
164 (32). HRMS(EI): m/z calcd for C14H9Br2N [M]+: 348.9102;
found: 348.9092.
(18) (a) Goo, D.-Y.; Woo, S. K. Org. Biomol. Chem. 2016, 14, 122.
(b) Bedford, R. B.; Betham, M. J. Org. Chem. 2006, 71, 9403.
(c) Ackermann, L.; Althammer, A. Angew. Chem. Int. Ed. 2007, 46,
1627. (d) Jean, D. J. S.; Poon, S. F.; Schwarzbach, J. L. Org. Lett.
2007, 9, 4894. (e) Laha, J. K.; Petrou, P.; Cuny, G. D. J. Org. Chem.
(28) Dobruchowska, E.; Glowacki, I.; Ulanski, J.; Sanetra, J.;
Pielichowski, J. Chem. Phys. 1994, 76, 2419.
(29) Pawluc, P.; Franczyk, A.; Walkowiak, J.; Herczycho, G.; Kubicki,
M.; Marciniec, B. Org. Lett. 2011, 13, 1976.
(30) Bordwell, F. G. Acc. Chem. Res. 1988, 21, 456.
© Georg Thieme Verlag Stuttgart · New York — Synlett 2017, 28, A–E