C-Te Cross-Coupling of Diaryl Ditellurides with Arylboronic Acids by Using Copper(I) Thiophene-2-carboxylate under Mild Conditions

Article abstract of DOI:10.1055/s-0037-1610324

We describe the successful cross-coupling of diaryl ditellurides with arylboronic acids by using copper(I) thiophene-2-carboxylate (CuTC) under mild conditions. Although other studies have reported that highly polar solvents (such as DMSO) or bases are required, this reaction was completed by using CuTC and common solvents under neutral conditions at room temperature. This cross-coupling reaction was performed with diaryl ditellurides and arylboronic acids bearing various groups, affording the corresponding diaryl tellurides in good to excellent yields.

Full text of DOI:10.1055/s-0037-1610324

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©
Georg Thieme Verlag Stuttgart · New York
2018, 29, A–E
letter
A
en
Synlett
S. Koguchi et al.
Letter
C–Te Cross-Coupling of Diaryl Ditellurides with Arylboronic
Acids by Using Copper(I) Thiophene-2-carboxylate under Mild
Conditions
Shinichi Koguchi*
O
Yuga Shibuya
S
O– Cu+
Yusuke Igarashi
R
B(OH)2
Te
Haruka Takemura
Te
Te
R'
R
R'
R
CH2Cl2
24 h, rt
Department of Chemistry, School of Science, Tokai University,
4
-1-1 Kitakaname, Hiratsuka, Kanagawa 259-1292, Japan
1
8 samples
koguchi@tokai-u.jp
Up to 94% yield
This reaction proceeds at room temperature.
No base or acid is required.
General-purpose solvents such as THF and methylene chloride can be used.
Tellurium coupling proceeds selectively.
Received: 28.08.2018
Accepted after revision: 15.10.2018
Published online: 15.11.2018
genides by the cross-coupling of arylboronic acids and sym-
metrical diaryl dichalcogenides have been reported. The
first C–Te and C–Se cross-coupling reactions of boronic
DOI: 10.1055/s-0037-1610324; Art ID: st-2018-u0562-l
acids with diaryl dichalcogenides by using CuI (and a bipyr-
Abstract We describe the successful cross-coupling of diaryl ditellu-
rides with arylboronic acids by using copper(I) thiophene-2-carboxylate
idine ligand) was reported by Taniguchi.4 His synthetic
method used aqueous DMSO as the solvent and required a
temperature of 100 °C. Wang and co-workers reported C–Te
and C–Se coupling reactions that used InBr or Fe (FeCl or
(
CuTC) under mild conditions. Although other studies have reported
that highly polar solvents (such as DMSO) or bases are required, this re-
action was completed by using CuTC and common solvents under neu-
tral conditions at room temperature. This cross-coupling reaction was
performed with diaryl ditellurides and arylboronic acids bearing various
groups, affording the corresponding diaryl tellurides in good to excel-
lent yields.
3
2
5
FeCl ), but these reactions required a high temperature of
3
130 °C. Kumar and Kumar recently succeeded in cross-
coupling arylboronic acids; however, their method required
6
NaBH as a reducing agent. A Cu(OAc) -catalyzed reaction
4
2
Key words C–Te coupling, copper catalysis, diaryl ditellurides, aryl-
boronic acids, diaryl tellurides
of diaryl tellurides with aryl trifluoroborates was reported
by Stefani and co-workers. More recently, a cross-coupling
7a
reaction of diaryl ditellurides and arylboronic acids by us-
7
b
Chalcogenide compounds have become attractive tar-
gets for synthesis because of their unique chemistry and
the resulting useful biological activities. Therefore, many
ing a silver catalyst was reported by Alves and co-workers.
However, these two reactions also required high tempera-
tures. All the developed methods have various disadvantag-
es, such as high reaction temperatures, expensive catalysts,
difficult removal steps, highly polar solvents, or an acidic or
basic (not neutral) additive. Additionally, few examples of
cross-coupling reactions specific to tellurium compounds
have been reported, as most of the reported examples in-
volve cross-coupling reactions between selenium or telluri-
um and other atomic groups.
In this study, we focused on copper(I) thiophene-2-
carboxylate (CuTC), which can be easily synthesized from
thiophene-2-carboxylic acid and Cu O (commercially avail-
able). CuTC is a good reagent for Ullmann coupling reac-
tions; however, its use in cross-coupling reactions of diaryl
dichalcogenides with arylboronic acids has not been re-
ported.
1
classes of organotellurium compounds have been prepared
and studied, and tellurides are certainly the most useful
and promising of these compounds in view of their useful-
2
3
ness in organic synthesis. In recent years, Oba et al. syn-
thesized symmetrical diaryl telluroxides and symmetrical
diaryl tellurones by oxidizing symmetrical diaryl tellurides.
In addition, the oxidation of alcohols and thiols by tellur-
3b
oxides or tellurones has been reported. However, only
symmetric telluroxides and tellurones were used in these
oxidation reactions. We were interested in performing oxi-
dation reactions by using asymmetric diaryl telluroxides or
asymmetric diaryl tellurones. Therefore, we examined effi-
cient methods for synthesizing asymmetric diaryl tellu-
rides.
2
To synthesize asymmetric diaryl tellurides, we chose a
readily available arylboronic acids and a conveniently syn-
thesizable symmetrical diaryl ditellurides as substrates.
Several methods for synthesizing asymmetric diaryl chalco-
Initially, we investigated the C–Te coupling of a diaryl
ditelluride with an arylboronic acid in several solvents. A
mixture of di(4-tolyl) ditelluride (0.5 mmol) and phenyl-
boronic acid (1.2 mmol) in the appropriate solvent (3 mL)
©
Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–E

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Synlett
S. Koguchi et al.
Letter
was stirred at room temperature for 30 minutes, and then
CuTC (1.2 mmol) was added. The reaction mixture was then
stirred at room temperate before the product was purified
and isolated
when diaryl ditellurides with bulky substituents, such as
dimesityl ditelluride or bis(2,4,6-triisopropylphenyl) ditel-
luride, were used (entries 9–12). The reaction mixtures
shown in entries 9 and 10 were heated, with the aim of im-
proving the yield; however, these reactions remained inef-
fective. (In entry 9, the yield at r.t. was 46% and the yield
upon heating was 45%; in entry 10, the yield at r.t. was 62%
and the yield upon heating was 64%.) When we used (4-
formylphenyl)boronic acid as a substrate, the yield de-
creased (entries 14–18); however, when the temperature
for these reactions was changed from room temperature to
reflux conditions, the yields of the reactions improved.
Finally, we examined the preparation of diaryl selenides us-
ing diaryl diselenides and arylboronic acids in this reaction
system; however, the intended diaryl selenides were not
obtained. In other words, this reaction system is unique for
the synthesis of diaryl tellurides by reacting diaryl ditellu-
rides and boronic acids.
The following experiment was conducted to clarify the
selectivity toward tellurium and selenium in this reaction.
Diphenyl ditelluride (1 equiv), diphenyl diselenide (1
equiv), and (4-methoxyphenyl)boronic acid (1 equiv) were
stirred in dichloromethane at room temperature for 30
minutes. CuTC (1 equiv) was then added and the mixture
was stirred at room temperature for 24 hours. (Scheme 1).
As a result, 1-methoxy-4-(phenyltelluro)benzene, the cou-
pling product of the ditelluride and the boronic acid, was
obtained in an isolated yield of 89%. Further, the unreacted
selenium compound (diphenyl diselenide) was recovered in
yield of 73%. This confirmed that this reaction is specific to
tellurium compounds.
When chloroform (CHCl ) or dichloromethane (CH Cl )
3
2
2
was used as the solvent, the product was obtained in good
yield (Table 1, entries 1 and 2). In particular, when dichloro-
methane was used, the yield of the product was 94%. The
yield was lower when a halogen-free solvent [tetrahydro-
furan (THF), ethyl acetate (EtOAc), or methanol (MeOH)]
was used (entries 4, 5, and 9). In the highly polar solvents
N,N-dimethylformamide (DMF) and dimethyl sulfoxide
(DMSO), the yield was further reduced (entries 7 and 8). We
then tested the ionic liquid 1-butyl-3-methylimidazolium
hexafluorophosphate ([bmim]PF ) as a solvent, with the
6
aim of recycling the reaction system; however, the coupling
reaction did not proceed in this solvent. A shorter reaction
time was examined in dichloromethane, the most suitable
solvent for this reaction, but the yield of the reaction was
poor (entry 3). Dichloromethane was therefore the most
suitable solvent for the C–Te coupling reaction of bis(4-
tolyl) ditelluride and phenylboronic in the presence of CuTC
with a reaction time of 24 hours.
Table 1 Optimization of the Reaction Conditionsa
Te)2
B(OH)2
Te
CuTC
solvent, rt
b
Entry
Solvent
CHCl
Time (h)
Yield (%)
1
2
3
4
5
6
7
8
9
3
24
24
6
77
94
58
40
25
15
13
7
CH
CH
2
Cl
2
2
Te
Te)2
2
Cl
O
THF
24
24
24
24
24
24
24
19
B(OH)2
89%
EtOAc
NMP
CuTC
O
CH2Cl2
Se)2
Se)2
24 h, rt
DMF
DMSO
MeOH
[bmim]PF
73%
34
n.r.c
Scheme 1
10
6
a
Reaction conditions: di(4-tolyl) ditelluride (0.5 mmol), PhB(OH)
1.2 mmol), CuTC (1.2 mmol), solvent (3 mL), r.t.
Isolated yield.
2
(
In summary, we have reported the C–Te cross-coupling
of diaryl ditellurides with arylboronic acids by using cop-
per(I) thiophene-2-carboxylate as a catalyst.8 The devel-
oped process is advantageous because the reaction pro-
ceeds at room temperature, a variety of organic solvents
can be used, and good yields are obtained. Moreover, this
reaction system is specific to the C–Te cross-coupling of di-
aryl ditellurides with arylboronic acids.
b
c
n.r. = no reaction.
We then examined the preparation of various substitut-
ed diaryl chalcogenides by using various diaryl dichalco-
genides and arylboronic acids in this reaction system. As a
result, a variety of diaryl tellurides were synthesized in rel-
atively good yields (Table 2). However, the yields decreased
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Synlett
S. Koguchi et al.
Letter
Table 2 C–Te Cross-Coupling of Diaryl Ditellurides with Arylboronic Acids in the Presence of CuTC a
Te)2
B(OH)2
Te
CuTC
R
R'
R
R'
CH2Cl2
24 h, rt
Entry
1
Dichalcogenide
Boronic acid
Product
Yield (%)b
Te
(4-TolTe)
2
PhB(OH)
PhB(OH)
2
2
94
82
1
Te
2
3
4
5
(PhTe)
2
2
OMe
Te
(4-TolTe)
(4-TolTe)
(2-TolTe)
2
2
2
2-MeOC
4-MeOC
6
H
4
B(OH)
2
2
88
74
84
3
Te
6
H
4
B(OH)
4
OMe
Te
PhB(OH)
2
5
OMe
Te
6
7
(2-TolTe)
(2-TolTe)
2
2
2-MeOC
4-MeOC
6
H
4
4
B(OH)
2
2
86
69
6
Te
6
H
B(OH)
OMe
Te
8
9
(MesTe)
(MesTe)
(MesTe)
2
2
2
PhB(OH)
2
82
8
OMe
Te
2-MeOC
4-MeOC
6
H
4
B(OH)
2
46 (45)c
62 (64)c
61
9
Te
1
0
1
6
H
4
B(OH)
2
OMe
10
Te
1
(2,4,6-i-PrC
6
H
2
Te)
2
PhB(OH)
2
H
11
O
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Synlett
S. Koguchi et al.
Letter
Table 2 (continued)
Entry
Dichalcogenide
Boronic acid
Product
Yield (%)b
i-Pr
OMe
Te
12
(2,4,6-i-PrC
6
H
2
Te)
2
2-MeOC
4-MeOC
6
H
4
B(OH)
2
56
i-Pr
i-Pr
12
i-Pr
Te
13
14
15
16
17
(2,4,6-i-PrC
6
H
2
Te)
2
6
H
4
B(OH)
2
88
i-Pr
i-Pr
OMe
13
Te
(PhTe)
2
4-HCOC
4-HCOC
4-HCOC
4-HCOC
6
6
6
6
H
H
H
H
4
4
4
4
B(OH)
B(OH)
B(OH)
B(OH)
2
2
2
2
H
31 (69)c
26 (82)c
22 (75)c
35 (57)c
14
O
i-Pr
Te
(2-TolTe)
(4-TolTe)
2
i-Pr
i-Pr
15
Te
2
H
16
O
Te
(MesTe)
2
H
17
O
i-Pr
Te
1
8
(2,4,6-i-PrC
6
H
2
Te)
2
4-HCOC
4-HCOC
6
H
4
B(OH)
2
40 (56)c
H
i-Pr
i-Pr
18
O
Se
Se
1
9
0
(PhSe)
(PhSe)
2
2
6
H
4
B(OH)
2
H
n.r.d
n.r.
O
2
PhB(OH)
2
a
b
c
2 2
Reaction conditions: diaryl dichalcogenide (0.5 mmol), arylboronic acid (1.2 mmol), CuTC (1.2 mmol), CH Cl (3 mL), r.t., 24 h.
Isolated yield.
Reflux conditions.
n.r. = no reaction.
d
Acknowledgment
Funding Information
I would particularly like to thank Dr. Yoshiki Oda for his valuable sup-
port on this work.
This work was supported by Tokai University General Research Orga-
nization Grant.()
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S. Koguchi et al.
Letter
Supporting Information
(4) Taniguchi, N. J. Org. Chem. 2007, 72, 1241.
(
5) (a) Ren, K.; Wang, M.; Wang, L. Org. Biomol. Chem. 2009, 7, 4858.
b) Wang, M.; Ren, K.; Wang, L. Adv. Synth. Catal. 2009, 351,
586.
Supporting information for this article is available online at
https://doi.org/10.1055/s-0037-1610324.
(
1
S
u
p
p
orit
n
g Inform ati
o
n
S
u
p
p
orti
n
g Inform ati
o
n
(6) Kumar, A.; Kumar, S. Tetrahedron 2014, 70, 1763.
(
7) (a) Alves, S.; Pena, J.; Vieira, A.; Botteselle, G.; Guadagnin, R.;
Stefani, H. J. Braz. Chem. Soc. 2009, 20, 988. (b) Goldani, B.;
Sacramento, M.; Lenardão, E.; Schumacher, R.; Barcellos, T.;
Alves, D. New J. Chem. 2018, 42, 15603.
References and Notes
(1) (a) Nogueira, C. W.; Zeni, G.; Rocha, J. B. Chem. Rev. 2004, 104,
6255. (b) Mugesh, G.; du Mont, W.-W.; Sies, H. Chem. Rev. 2001,
(8) Diaryl Tellurides 1–10; General Procedure
101, 2125. (c) Parnham, M. J.; Graf, E. Prog. Drug Res. 1991, 36, 9.
The appropriate diaryl ditelluride (0.5 mmol) and arylboronic
acid (1.2 mmol) were stirred in CH Cl (3 ml) at r.t. for 30 min.
(
2) (a) Zeni, G.; Braga, A. L.; Stefani, H. A. Acc. Chem. Res. 2003, 36,
31. (b) Zeni, G.; Lüdtke, D. S.; Panatieri, R. B.; Braga, A. L. Chem.
2
2
7
CuTC (1.2 mmol) was then added and the mixture was stirred at
r.t. for 24 h. The mixture was concentrated, and the product was
purified by column chromatography.
Rev. 2006, 106, 1032. (c) Petragnani, N.; Stefani, H. A. Tetrahe-
dron 2005, 61, 1613. (d) Comasseto, J. V.; Ling, L. W.; Petragnani,
N.; Stefani, H. A. Synthesis 1997, 1997, 373.
1-Phenyl-4-(phenyltelluro)benzene (1)
(
3) (a) Oba, M.; Nishiyama, K.; Koguchi, S.; Shimada, S.; Ando, W.
Organometallics 2013, 32, 6620. (b) Oba, M.; Tanaka, K.;
Nishiyama, K.; Ando, W. J. Org. Chem. 2011, 76, 4173. (c) Oba,
M.; Okada, Y.; Endo, M.; Tanaka, K.; Nishiyama, K.; Shimada, S.;
Ando, W. Inorg. Chem. 2010, 49, 10680. (d) Okada, Y.; Oba, M.;
Arai, A.; Tanaka, K.; Nishiyama, K.; Ando, W. Inorg. Chem. 2010,
Yellow oil; yield: 274.5 mg (0.93 mmol; 94%); R = 0.35 (hexane).
f
1
H NMR (500 MHz, CDCl ): δ = 2.25 (s, 3 H), 6.95–7.56 (m, 9 H).
C NMR (125 MHz, CDCl ): δ = 21.3, 110.3, 115.3, 127.6, 129.5
3
13
3
(
2 C), 130.5 (2 C), 137.3 (2 C), 138.1, 138.8 (2 C). HRMS (APCI):
+
m/z [M + H] calcd for C13H13Te: 299.0079; found: 299.02484.
49, 383. (e) Oba, M.; Okada, Y.; Nishiyama, K.; Ando, W. Org.
Lett. 2009, 11, 1879.
©
Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–E