Efficient conversion of carbon dioxide at atmospheric pressure to 2-oxazolidinones promoted by bifunctional Cu(ii)-substituted polyoxometalate-based ionic liquids

Article abstract of DOI:10.1039/c5gc02311d

Copper(ii) substituted polyoxometalate-based ionic liquids e.g. [(ⁿC₇H₁₅)₄N]₆[α-SiW₁₁O₃₉Cu] were successfully developed as halogen-free bifunctional catalysts for the carboxylati

Full text of DOI:10.1039/c5gc02311d

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PAPER
Efficient conversion of carbon dioxide at atmospheric pressure
to 2-oxazolidinones promoted by bifunctional Cu(II)-substituted
polyoxometalate-based ionic liquids†
Received 00th January 20xx,
Accepted 00th January 20xx
MeiꢀYan Wang, QingꢀWen Song, Ran Ma, JiaꢀNing Xie and LiangꢀNian He*
DOI: 10.1039/x0xx00000x
Copper (II) substituted polyoxometalateꢀbased ionic liquid e.g. [(nC7H15)4N]6[αꢀSiW11O39Cu] was successfully developed as
a halogenꢀfree bifunctional catalyst for the carboxylative cyclization of propargylic amines with CO2. Such a CO2 fixation
protocol proceeded smoothly at atmospheric pressure under solventꢀfree conditions, featuring as an environmentally benign
and low energyꢀinput manner. Notably, various of propargylic amines could react smoothly to afford 2ꢀoxazolidinones as
target products in high to quantitative yields. Furthermore, dual activation of both propargylic amine and CO2 by
[(nC7H15)4N]6[αꢀSiW11O39Cu] was studied through NMR technique and control experiments.
www.rsc.org/
Introduction
tetrahydrofuran as solvent.13 Subsequently, numerous catalytic
systems including super bases,14 silver,15 ꢀBuOI,16 and
t Nꢀ
Carbon dioxide chemistry has drawn much attention in the last
two decades as CO2 is an abundant, nontoxic, nonꢀflammable,
easily available, and renewable C1 resource. Various useful
chemicals, such as dimethyl carbonate,1 urethanes,2 formic
acid,3 methanol,4 cyclic carbonates,5 polycarbonates,6 and
others have been prepared by using CO2 as a feedstock.
However, compared with traditional C1 sources (e.g., carbon
monoxide and phosgene), its thermodynamically stable and
kinetically inert are still the main obstacles in developing
practical processes to convert CO2 into useful chemicals.
Therefore, the exploration of efficient catalysts would be
crucial to realize CO2 conversion.
heterocyclic carbineꢀAu complexes17 have been developed.
Very recently, Han and coꢀworkers reported an effective protic
ionic liquids as both nonꢀmetal catalyst and solvent for the
a
carboxylative cyclization of propargylic amines with CO2.12
They demonstrated that the activation of amino group is crucial
and the intramolecular cyclization is the rateꢀdetermining step.
Despite the significant advances in the past few decades, the
example of CO2 utilization at atmospheric pressure is limited.
Therefore, development of alternative methodologies for the
synthesis of 2ꢀoxazolidinones using CO2 under mild conditions
is still highly desirable.
2ꢀOxazolidinones are important heterocyclic chemicals
playing a significant role as chemical intermediates7 and chiral
auxiliaries8 in organic synthesis, and as antibacterial drugs9 in
pharmaceutical chemistry. Therefore, many efforts have been
dedicated to synthesize these useful heterocycles, such as
catalytic asymmetric intermolecular aminopalladation10 and
formal [3+2] cycloaddition reaction.11 Recently, the
employment of CO2 as C1 building block to construct
oxazolidinone motifs has attracted considerable attention.12 One
of the most promising examples of CO2 fixation to access 2ꢀ
oxazolidinones is the carboxylative cyclization of propargylic
amines with CO2 (Scheme 1), which stands for an important
clean and atom economic reaction. As early as in 1964,
Scheme 1 Carboxylative cyclization of propargylic amines with CO2.
Polyoxometalate (POM), as a class of large cluster of metalꢀ
oxide units, has been widely used in many fields due to their
excellent properties.18 For example, behaving the oxygenꢀrich
structure, heteropoly acid anions have rich negative charge on
the O atom and strong nucleophilicity, leading to being able to
activate CO2 molecule via the formation of the CO2ꢀaddult.19,20
Recently, polyoxometalateꢀbased ionic liquids have received
considerable interest in epoxidation,21 deep desulfurization of
fuels,22 esterification,23 and so on.24 Notably, excellent POMꢀ
based catalysis has also been applied in the cycloaddition of
epoxides and CO2,25 direct conversion of styrene into styrene
carbonate,26 and reduction of CO2.19
Dimroth and Pasedach developed
a practicable copperꢀ
promoted carboxylative cyclization protocol with benzene or
State Key Laboratory and Institute of ElementoꢀOrganic Chemistry, Collaborative
Innovation Center of Chemical Science and Engineering, Nankai University,
Tianjin 300071, P. R. China. Eꢀmail: heln@nankai.edu.cn.
Fax: (+86) 22ꢀ23503878; Tel: (+86) 22ꢀ23503878
† Electronic supplementary information (ESI) available: General procedures,
spectral data or other electronic format. See DOI: 10.1039/x0xx00000x
On the other hand, copper salts are widely employed as
activators of the C≡C bond in organic synthesis.27 We
envisioned that the POM anion could activate both the N–H
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bond of propargylic amine and CO2 leading to the generation of 2ꢀoxazolidinones.29 In addition, bulky tetraalkylammonium cation
the carbamate intermediate, the C≡C bond in which is activated increases the solubility of the polyoxometalate compared with
by the Cu(II) species, thus promotes the intramolecular potassium cation, leading to higher catalytic activity.
nucleophilic cyclization to afford 2ꢀoxazolidinones. As
Table 1 POMꢀpromoted reaction of CO2 with propargylic amine 1aa
expected, [(nC7H15)4N]6[αꢀSiW11O39Cu] could be served as a
wellꢀdefined singleꢀcomponent bifunctional catalyst for
simultaneously activating propargylic amines as well as CO2
molecule (Scheme 2), and thus rendered the reaction to
efficiently proceed at low CO2 pressure. Furthermore, the
cation and anion of [(nC7H15)4N]6[αꢀSiW11O39Cu] have
Entry
1
Cat./%
Conv./%
0
Yieldb/%
synergistic effects in catalyzing the reaction.
ꢀ
0
2
(nC7H15)4NBr
0
0
3
K8[αꢀSiW11O39]
0
0
4
K6[SiW11O39Cu]
45
43
67
68
96
66
18
16
45
43
95
Scheme 2 Interaction of [(nC7H15)4N]6[
αꢀSiW11O39Cu] with CO2 and propargylic
amine.
5
CuCl2
78
6 c
CuCl2+(nC7H15)4NBr
[(nC7H15)4N]6[αꢀSiW11O39Cu]
[(nC7H15)4N]6[αꢀSiW11O39Co]
[(nC7H15)4N]6[αꢀSiW11O39Fe]
[(nC7H15)4N]6[αꢀSiW11O39Ni]
[(nC7H15)4N]6[αꢀSiW11O39Zn]
[(nC7H15)4N]6[αꢀSiW11O39Mn]
[(nC4H9)4N]6[αꢀSiW11O39Cu]
91
7
>99
70
Results and discussion
8
A series of transitionꢀmetalꢀsubstituted polyoxometalateꢀbased ionic
liquids [(nC7H15)4N]6[αꢀSiW11O39M] (M = Cu(II), Co(II), Fe(II),
Ni(II), Zn(II), Mn(II)) were synthesized according to the published
procedures (see Supporting Information).20a,28 The carboxylative
cyclization of Nꢀbenzylpropꢀ2ꢀynꢀ1ꢀamine (1a) was initially chosen
as the model reaction under a CO2 balloon in the absence of any
solvent at 60 °C as summarized in Table 1. The reaction without a
catalyst was carried out only to recover the starting material
quantitatively (entry 1). (nC7H15)4NBr and K8[αꢀSiW11O39] were
found to be ineffective (entries 2ꢀ3). Interestingly, K6[αꢀ
SiW11O39Cu], CuCl2, a mixture of CuCl2 and (nC7H15)4NBr showed
moderate activity (entries 4ꢀ6), thus indicating the promotion effect
of Cu(II) as expected. It was also worth mentioning that K8[αꢀ
SiW11O39] allowed the reaction to produce the carbamate rather than
2ꢀoxazolidinone 2a (entry 3, see Supporting Information, Scheme
S1), also supporting the activation of both propargylic amine and
CO2 by POM anion. Those inspired us to investigate the catalysis of
[(nC7H15)4N]6[αꢀSiW11O39Cu]. Gratifyingly, 96% yield of 3ꢀbenzylꢀ
5ꢀmethyleneoxazolidinꢀ2ꢀone (2a) was obtained under the given
conditions (entry 7). In this context, several transition metalꢀ
substituted polyoxometalateꢀbased ionic liquids [(nC7H15)4N]6[αꢀ
SiW11O39M] [M = Co(II), Fe(II), Ni(II), Zn(II), Mn(II)] were also
screened. Among the tested [(nC7H15)4N]6[αꢀSiW11O39M],
[(nC7H15)4N]6[αꢀSiW11O39Cu] showed much higher catalytic activity
than Co(II), Fe(II), Ni(II), Zn(II), Mn(II) counterparts under the
identical reaction conditions (entry 7 vs. 8ꢀ12), indicating efficient
activation ability of Cu(II) in the [αꢀSiW11O39Cu]6ꢀ on the C≡C
9
18
10
11
12
13
18
45
47
>99
[(nC16H33)(CH3)3N+]6[αꢀ
14
94
79
86
73
SiW11O39Cu]
[(nC7H15)4N]6[αꢀSiW11O39Cu]
15d
a
Unless otherwise specified, the reactions were performed with 1a (145.2
mg, 1.0 mmol), catalyst (molar percentage to 1a, 2.5 mol%, CO2 balloon, 60
oC, 20 h. b Determined by 1H NMR technique, using 1,1,2,2ꢀtetrachloroethane
as internal standard. a mixture of CuCl2 (2.5 mol%) + (nC7H15)4NBr (15
c
mol%), d 25 oC.
Moreover, owing to efficient catalytic activity of
[(nC7H15)4N]6[
αꢀSiW11O39Cu], the reaction could also
proceeded well even at ambient temperature (entry 15).
The carboxylative cyclization for a variety of propargylic
amines was then undertaken to explore the scope of this wellꢀ
developed [(nC7H15)4N]6[
αꢀSiW11O39Cu] catalytic system. As
shown in Table 2, both terminal and internal propargylic
amines performed smoothly to give the corresponding 2ꢀ
oxazolidinones in excellent yields (entries 1ꢀ7). In general,
substituents at the propargylic position of propargylic amines
have remarkable effect on the reaction outcome, where the
geminal dialkyl inhibited the reaction, probably due to the steric
hindrance (entry 8). Notably, paraꢀsubstituent at benzene ring
of the terminal position increased the reactivity for the
carboxylative cyclization reaction for obviously shortened
reaction time (entries 6, 7 vs. 3).
bond
.
On the other hand, the (nC7H15)4N+ was found to be favorable for
this reaction in comparison with potassium cation (entry 7 vs. 4). In
addition, other bulky tetraalkylammonium cations such as
(nC4H9)4N+ and (nC16H33)(CH3)3N+ also gave good results (entries 13,
14). This is understandable because the bulky tetraalkylammonium
cation can not only stabilize the carbamate intermediate, but enhance
its solubility and Oꢀnucleophilicity, and thus promote subsequent
intramolecular nucleophilic cyclization resulting in the formation of
2 | J. Name., 2012, 00, 1-3
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Table 2 Substrate scopea
supports the CO2 activation by the [
α
ꢀSiW11O39Cu]6ꢀ,31 whilst
the signal at 124.7 ppm is due to the physical absorption of CO2.
Entry
1
Substrate
Product
Yielde/%
96
1a
1b
2a
2b
2
3
92
95
nBu
Fig. 1. 1H NMR investigation. (a) [(nC7H15)4N]6[
αꢀSiW11O39Cu] (50 mg, 0.01
HN
mmol) in 0.3 mL of CDCl3. (b) 1a (55 mg, 0.4 mmol) in 0.3 mL of CDCl3; (c) 1a
(55 mg, 0.4 mmol), [(nC7H15)4N]6[
of CDCl3.
αꢀSiW11O39Cu] (50 mg, 0.01 mmol) in 0.3 mL
Ph
1c
2c
4b
94
93
1d
2d
HN
5
Ph
2e
Ph
1e
Fig. 2. 13C NMR study. [(nC7H15)4N]6[
αꢀSiW11O39Cu] (containing a small amount
of toluene) in CDCl3 at atmospheric CO2 (25 oC).
6b,c
92
On the basis of experimental and NMR studies, a plausible
mechanism for the [(nC7H15)4N]6[
αꢀSiW11O39Cu] promoted
2f
1f
fixation of CO2 with propargylic amine is proposed as
illustrated in Scheme 3, taking the carboxylative cyclization of
1a as an example. Propargylic amine and CO2 are activated by
7b,d
99
0
2g
1g
[(nC7H15)4N]6[
αꢀSiW11O39Cu] in the form of species I. Then,
the activated propargylic amine and CO2 are further converted
into the carbamate II under the participation of another
molecular propargylic amine which obtains a proton to
converted into the ammonium cation [1a+H]+. Compared with
8b
1h
2h
a
1a+H]+, the bulky tetraheptylammonium cation (Q) can not
only stabilize the carbamate anion, but also enhance the Oꢀ
Unless otherwise stated, all the reactions were carried out with 1 mmol of
propargylic amine, [(nC7H15)4N]6[αꢀSiW11O39Cu] (130.0 mg, 0.025 mmol),
CO2 (99.999%, balloon), 60 oC, 20 h. b 0.3 mL EtOH as solvent. c 2 h. d 10 h. e
Determined by 1H NMR technique.
[
+
nucleophilicity, so it could exchange with [1a+H
] to form
favorable carbamate III. Subsequently, in aid of activation of
C≡C bond by Cu(II), intramolecular nucleophilic cyclization of
III gives the intermediate IV. Finally, protoꢀdemetallation with
the help of proton carrier [1a+H]+ affords the product 2a along
To further verify our initial assumption that both the
propargylic amine and CO2 could be activated by
[(nC7H15)4N]6[
[(nC7H15)4N]6[
α
α
ꢀSiW11O39Cu],
the
interaction
of
with the regeneration of [(nC7H15)4N]6[
αꢀSiW11O39Cu].
ꢀSiW11O39Cu] with CO2 and 1a was monitored
respectively by 1H and 13C NMR technique as depicted in Fig. 1
and 2. In the 1H NMR spectrum, the NꢀH signal of 1a appeared
Conclusions
at
when [(nC7H15)4N]6[
thus illustrating that the propargylic amine is activated by
[(nC7H15)4N]6[
ꢀSiW11O39Cu] through the formation of
N−H
O hydrogen bonding.30 Two new signals appeared at
157.9 and 124.7 ppm when CO2 was bubbled into a dry
solution of [(nC7H15)4N]6[
ꢀSiW11O39Cu] and CDCl3 (Fig. 2).
δ
= 1.68 ppm (Fig. 1b). However, this signal disappeared
α
ꢀSiW11O39Cu] was added to 1a (Fig. 1c),
In summary, we have described a costꢀcompetitive catalytic
process promoted by robust bifunctional [(nC7H15)4N]6[
α
ꢀ
α
SiW11O39Cu] which can simultaneously activate both CO2 and
propargylic amine for efficient chemical fixation of CO2 at
atmospheric pressure to produce 5ꢀalkylideneoxazolidinꢀ2ꢀones
at room temperature in excellent yields. This protocol also
features a simple process with low energy consumption and
avoidance of complicated preparation of the catalyst. Such
findings may be of great interest to develop costꢀeffective,
…
δ =
α
The newlyꢀappeared peak at 157.9 ppm assigned to the
carbonyl carbon of the monodentate carbonate presumably
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halogenꢀfree and efficient bifunctional catalysts for the balloon (99.999%). Upon completion, product yield was
preparation of the CO2ꢀbased products under mild reaction determined by 1H NMR technique using 1,1,2,2ꢀ
conditions.
tetrachloroethane as an internal standard. Then the reaction
mixture was diluted with dichlormethane (2 mL). The organic
phase was collected and then purified by column
chromatography on silica gel using petroleum ether/ethyl
acetate as an eluent to afford the desired product. All the
products were characterized by NMR and MS and compared
O
O
Bn
N
Bn
O
C
HN
1a
+
Q6[a-SiW11O39Cu]
Q = (nC7H15)4N+
O
2a
e
,32
with the data available in the literature.12
1a
[1a+H]+
3-benzyl-5-methyleneoxazolidin-2-one
(2a)
crystalline solid, m.p. 53ꢀ54 C; H NMR (400 MHz, CDCl3)
7.40ꢀ7.27 (m, 5H), 4.72 (dd, = 5.6 Hz, = 2.8 Hz, 1H), 4.47 (s,
2H), 4.20 (dd, = 5.2 Hz, = 2.4 Hz, 1H), 4.02 (t, = 2.4 Hz,
2H) ppm. 13C NMR (101 MHz, CDCl3)
155.6, 148.8, 134.8,
.
White
o
1
δ
O
O
C
O
J
J
O
Q6[a-SiW11O39Cu]
J
J
J
N
Bn
δ
H
Bn
N
Q6[a-SiW11O39Cu]
128.98, 128.9, 128.2, 128.1, 86.7, 47.8, 47.1 ppm. GCꢀMS (EI,
70 eV) m/z (%) = 189 (19), 92 (52), 91 (100), 65 (16).
IV
I
3-butyl-5-methyleneoxazolidin-2-one (2b). Pale yellow oil;
Q+
O
1a
1H NMR (400 MHz, CDCl3)
J
δ
4.65 (d,
= 2.4 Hz, 2H), 3.24 (t,
2H), 1.52ꢀ1.44 (m, 2H), 1.33ꢀ1.24 (m, 2H), 0.88 (t,
3H) ppm. 13C NMR (101 MHz, CDCl3)
J = 2.4 Hz, 1H), 4.24 (d,
O
N
Bn
H2N Bn
= 2.4 Hz, 2H), 4.12 (d,
J
J
J
= 7.2 Hz,
= 7.2 Hz,
III
[1a+H]+
Q5[a-SiW11O39Cu]-
[1a+H]+
δ
155.4, 149.1, 86.1,
[1a+H]+
47.6, 43.3, 29.1, 19.6, 13.5 ppm. GCꢀMS (EI, 70 eV) m/z (%) =
O
155 (90), 113 (27), 112 (100), 98 (11), 84 (37).
[1a+H]+
O
(
Z
)-5-benzylidene-3-butyl-4-ethyloxazolidin-2-one
Pale yellow oil; 1H NMR (400 MHz, CDCl3)
7.62 (d,
Hz, 2H), 7.35 (dd, = 7.2 Hz, = 12.8 Hz, 2H), 7.22 (dd,
6.8 Hz, = 12.8 Hz, 1H), 5.48 (s, 1H), 4.56 (s, 1H), 3.66ꢀ3.56
(2c)
= 7.6
J =
.
N
Bn
δ
J
J
J
Q6[a-SiW11O39Cu]
II
J
Scheme 3. Plausible mechanism for the [(nC7H15)4N]6[
αꢀSiW11O39Cu]ꢀcatalyzed
(m, 1H), 3.06ꢀ2.98 (m, 1H), 1.97ꢀ1.93 (m, 1H), 1.78ꢀ1.75 (m,
1H), 1.62ꢀ1.54 (m, 2H), 1.41ꢀ1.34 (m, 2H), 0.99ꢀ0.87 (m, 6H)
carboxylative cyclization of propargylic amines and CO2
ppm. 13C NMR (101 MHz, CDCl3)
δ 155.3, 146.7, 133.7, 128.3,
126.7, 102.3, 59.0, 41.1, 29.2, 24.9, 19.9, 13.7, 6.5 ppm. GCꢀ
MS (EI, 70 eV) m/z (%) = 259 (14), 230 (100), 174 (51), 118
(26), 90 (22).
Experimental section
Transitionꢀmetalꢀsubstituted
liquids were synthesized according to the previous reports.20
Taking the synthesis of [(nC7H15)4N]6[
ꢀSiW11O39Cu] as an
polyoxometalateꢀbased
ionic
(Z)-5-benzylidene-3-butyl-4-phenyloxazolidin-2-one (2d).
a
,28
o
White crystalline solid, m.p. 103ꢀ104 C; 1H NMR (400 MHz,
α
CDCl3) 7.56 (d, = 7.6 Hz, 2H), 7.46 (d, = 6.0 Hz, 3H),
δ
J
J
example: 25 mL of 20 mM aqueous K8[αꢀSiW11O39] solution
and 50 mL of a 10 mM aqueous CuCl2 solution were mixed and
stirred for 15 min. Then the solution was treated with
tetraheptylammonium bromide (2.47 g, 3 mmol) dissolved in
60 mL toluene. After the two phases was allowed to settle for
10 minutes, the organic layer was decanted and washed seven
times with 20 mL water portions. The wet toluene was removed
by heating to 40 °C under vacuum. Then 30 mL dry toluene
was added and evaporated under reduced pressure to remove
7.37ꢀ7.29 (m, 4H), 7.21 (m, 1H), 5.41 (s, 1H), 5.28 (s, 1H),
3.58ꢀ3.50 (m, 1H), 2.89ꢀ2.82 (m, 1H), 1.52ꢀ1.45 (m, 2H), 1.37ꢀ
1.26 (m, 2H), 0.91 (t,
MHz, CDCl3) 155.1, 147.8, 137.4, 133.5, 129.46, 129.42,
J
= 7.2 Hz, 6H) ppm. 13C NMR (101
δ
128.5, 128.4, 127.9, 127.0, 104.6, 63.9, 41.7, 29.0, 19.9, 13.7
ppm. GCꢀMS (EI, 70 eV) m/z (%) = 333 (22), 208 (56), 207
(70), 180 (100), 179 (44).
(Z)-5-benzylidene-3-cyclohexyl-4-phenyloxazolidin-2-one
o
(2e). White crystalline solid, m.p. 121ꢀ123 C; 1H NMR (400
MHz, CDCl3) 7.53 (d, = 8 Hz, 2H), 7.44ꢀ7.38 (m, 5H), 7.30
(t, = 7.6 Hz, 2H), 7.19 (t, = 7.6 Hz, 1H), 5.42 (s, 1H), 5.18
(s, 1H), 3.56 (t, = 7.2 Hz, 1H), 1.81ꢀ1.56 (m, 6H), 1.29ꢀ0.96
(m, 4H) ppm. 13C NMR (101 MHz, CDCl3)
154.7, 148.4,
the traces of water. The [(nC7H15)4N]6[
αꢀSiW11O39Cu] was
δ
J
obtained as a blue viscous liquid. IR (neat, KBr): 2955, 2927,
2856, 1638, 1618, 1465, 1383, 1265, 949, 898, 798, 739 cmꢀ1.
J
J
J
Anal. Calcd for [(nC7H15)4N]6[
α
ꢀSiW11O39Cu] (MW = 5202): C
38.78, H 6.98, N 1.62, Found: C 38.19, H 6.80, N 1.66.
General procedure for the synthesis
alkylideneoxazolidinꢀ2ꢀones: ꢀSiW11O39Cu]
[(nC7H15)4N]6[
δ
139.6, 133.6, 129.2, 128.4, 128.3, 127.8, 126.8, 104.2, 63.2,
54.7, 31.2, 30.0, 25.7, 25.1 ppm. GCꢀMS (EI, 70 eV) m/z (%) =
307 (33), 262 (10), 208 (29), 207 (28), 180 (100), 179 (66).
of
5ꢀ
α
(130.0 mg, 0.025 mmol) and propargylic amine (1 mmol) were
added to a 10 mL Schlenk tube equipped with a magnetic stir
bar. The flask was capped and sealed. Then a gasꢀexchanging
process was conducted using the “freezeꢀpumpꢀthaw” method.
The reaction mixture was stirred at 60 °C for 20 h under CO2
(Z)-5-(4-bromobenzylidene)-3-butyl-4-phenyloxazolidin-
o
1
2-one (2f). White crystalline solid, m.p. 119ꢀ120 C; H NMR
(400 MHz, CDCl3) 7.42ꢀ7.31 (m, 9H), 5.36 (s, 1H), 5.18 (s,
1H), 3.54ꢀ3.47 (m, 1H), 2.85ꢀ2.78 (m, 1H), 1.46ꢀ1.41 (m, 2H),
1.29ꢀ1.24 (m, 2H), 0.87 (t,
= 7.2 Hz, 3H) ppm. 13C NMR (101
δ
J
4 | J. Name., 2012, 00, 1-3
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DOI: 10.1039/C5GC02311D
Journal Name
MHz, CDCl3)
ARTICLE
Diao, R.ꢀG. Li, W. Li and L.ꢀN. He, Green Chem., 2014, 16,
1633ꢀ1638; ( ) B.ꢀS. Wang, E. H. M. Elageed, D.ꢀW. Zhang,
S.ꢀJ. Yang, S. Wu, G.ꢀR. Zhang, G.ꢀH. Gao, Chemcatchem
2014, 6, 278ꢀ283; ( ) D. Adhikari, A. W. Miller, M.ꢀH. Baik,
δ
154.9, 148.5, 137.1, 132.5, 131.6, 129.9, 129.6,
f
129.5, 127.9, 120.7, 103.5, 64.0, 41.7, 29.0, 19.9, 13.7 ppm.
GCꢀMS (EI, 70 eV) m/z (%) = 387 (33), 385 (33), 288 (17), 286
(17), 261 (14), 259 (14), 178 (100), 179 (91).
,
g
S. T. Nguyen, Chem. Sci., 2015, 6, 1293ꢀ1300.
(Z)-3-butyl-5-(4-methylbenzylidene)-4-phenyloxazolidin-
13 P. Dimroth and H. Pasedach, DE Pat., 1164411, 1964.
2-one (2g). White crystalline solid, m.p. 125ꢀ126 C; 1H NMR
(400 MHz, CDCl3) 7.42ꢀ7.40 (m, 5H), 7.33 (d, = 7.2 Hz,
2H), 7.11ꢀ7.09 (d, = 7.2 Hz, 2H), 5.37 (s, 1H), 5.22 (s, 1H),
3.54ꢀ3.47 (m, 1H), 2.85ꢀ2.78 (m, 1H), 2.31 (s,1H), 1.51ꢀ1.40
(m, 2H), 1.33ꢀ1.23 (m, 2H), 0.87 (t,
= 7.2 Hz, 3H) ppm. 13
NMR (101 MHz, CDCl3) 155.2, 147.0, 137.5, 136.8, 130.7,
o
14 (
Dalmonego, J. Chem. Soc., Perkin Trans. 1, 1998, 1541ꢀ
1546; ( ) M. Costa, G. P. Chiusoli and M. Rizzardi, Chem.
Commun., 1996, 32, 1699ꢀ1700; ( ) R. Nicholls, S. Kaufhold
and B. N. Nguyen, Catal. Sci. Technol., 2014, 4, 3458ꢀ3462.
15 ( ) S. Yoshida, K. Fukui, S. Kikuchi and T. Yamada, Chem.
Lett., 2009, 38, 786ꢀ787; ( ) S. Kikuchi, S. Yoshida, Y.
Sugawara, W. Yamada, H.ꢀM. Cheng, K. Fukui, K. Sekine, I.
Iwakura, T. Ikeno and T. Yamada, Bul. Chem. Soc. Jpn.
2011, 84, 698ꢀ717; ( ) M. Yoshida, T. Mizuguchi and K.
Shishido, Chem. Eur. J., 2012, 18, 15578ꢀ15581.
a) M. Costa, G. Paolo Chiusoli, D. Taffurelli and G.
δ
J
b
J
c
J
C
a
b
δ
129.4, 129.2, 128.3, 127.9, 104.6, 63.9, 41.7, 29.0, 21.3, 19.9,
13.7 ppm. GCꢀMS (EI, 70 eV) m/z (%) = 321 (44), 207 (24),
194 (100), 179 (64), 132 (19).
,
c
16 Y. Takeda, S. Okumura, S. Tone, I. Sasaki and S. Minakata,
Org. Lett., 2012, 14, 4874ꢀ4877.
17 S. Hase, Y. Kayaki and T. Ikariya, Organometallics, 2013,
32, 5285ꢀ5288.
Acknowledgements
We are grateful to the National Natural Science Foundation of
China, the Specialized Research Fund for the Doctoral Program
of Higher Education (20130031110013), the MOE Innovation
Team (IRT13022) of China, and the “111” Project of Ministry
of Education of China (project No. B06005) for financial
support.
18 (
Archer and E. P. Giannelis, J. Am. Chem. Soc., 2004, 126,
15358ꢀ15359; ( ) S.ꢀS. Wang and G.ꢀY. Yang, Chem. Rev.
2015, 115, 4893ꢀ4962.
19 M. Girardi, S. Blanchard, S. Griveau, P. Simon, M.
a) A. B. Bourlinos, K. Raman, R. Herrera, Q. Zhang, L. A.
b
,
Fontecave, F. Bedioui and A. Proust, Eur. J. Inorg. Chem.
2015, 2015, 3642ꢀ3648.
,
20 (a) S. H. Szczepankiewicz, C. M. Ippolito, B. P. Santora, T. J.
Vande Ven, G. A. Ippolito, L. Fronckowiak, F. Wiatrowski,
T. Power and M. Kozik, Inorg. Chem., 1998, 37, 4344ꢀ4352.
References
(
b
) G.ꢀG. Gao, F.ꢀY. Li, L. Xu, X.ꢀZ. Liu and Y.ꢀY. Yang, J.
Am. Chem. Soc., 2008, 130, 10838ꢀ10839.
21 ( ) N. S. Antonova, J. J. Carbó, U. Kortz, O. A. Kholdeeva
and J. M. Poblet, J. Am. Chem. Soc., 2010, 132, 7488ꢀ7497;
) Y. Leng, J. Zhao, P. Jiang and J. Wang, ACS Appl. Mater.
1
(
a
) M. He, Y. Sun, B. Han, Angew. Chem., Int. Ed., 2013, 52,
9620ꢀ9633; (b) P. Tundo and M. Selva, Acc. Chem. Res.
2002, 35, 706ꢀ716; ( ) M. Honda, M. Tamura, Y. Nakagawa
and K. Tomishige, Catal. Sci. Technol., 2014, 4, 2830ꢀ2845;
) A.ꢀH. Liu, Y.ꢀN. Li and L.ꢀN. He, Pure Appl. Chem.,
,
a
c
(
b
(d
Inter., 2014, 6, 5947ꢀ5954.
2012, 84, 581ꢀ602.
M. Yoshida, N. Hara and S. Okuyama, Chem. Commun.
2000, 36, 151ꢀ152.
R. Tanaka, M. Yamashita and K. Nozaki, J. Am. Chem. Soc.
2009, 131, 14168ꢀ14169.
22 W.ꢀL. Huang, W.ꢀS. Zhu, H.ꢀM. Li, H. Shi, G. Zhu, H. Liu
and G.ꢀY. Chen, Ind. Eng. Chem. Res., 2010, 49, 8998ꢀ9003.
23 Y. Leng, J. Wang, D.ꢀR. Zhu, X.ꢀQ. Ren, H.ꢀQ. Ge and L.
Shen, Angew. Chem., Int. Ed., 2009, 48, 168ꢀ171.
2
3
4
5
,
,
24 (a) T. Yamase, Chem. Rev., 1998, 98, 307ꢀ326; (b) S.
S. Wesselbaum, T. vomStein, J. Klankermayer and W.
Leitner, Angew. Chem., Int. Ed., 2012, 51, 7499ꢀ7502.
Herrmann, M. Kostrzewa, A. Wierschem and C. Streb,
Angew. Chem., Int. Ed., 2014, 53, 13596ꢀ13599.
(a
) M. Honda, M. Tamura, K. Nakao, K. Suzuki, Y.
Nakagawa and K. Tomishige, ACS Catal., 2014, 4, 1893ꢀ
1896; ( ) Q.ꢀW. Song, W.ꢀQ. Chen, R. Ma, A. Yu, Q.ꢀY. Li,
Y. Chang and L.ꢀN. He, ChemSusChem, 2015, 8, 821ꢀ827; (
25 (
a
) M. Sankar, N. H. Tarte and P. Manikandan, Appl. Catal.
, 2004, 276, 217ꢀ222; ( ) H. Yasuda, L.ꢀN. He, T. Sakakura
and C. Hu, J. Catal., 2005, 233, 119ꢀ122; ( ) J. Langanke, L.
A
b
b
c
c
)
Greiner and W. Leitner, Green Chem., 2013, 15, 1173ꢀ1182.
26 J.ꢀL. Wang, J.ꢀQ. Wang, L.ꢀN. He, X.ꢀY. Dou and F. Wu,
Green Chem., 2008, 10, 1218ꢀ1223.
27 M. Meldal and C. W. Tornøe, Chem. Rev., 2008, 108, 2952ꢀ
3015.
B. A. Vara, T. J. Struble, W. Wang, M. C. Dobish and J. N.
Johnston, J. Am. Chem. Soc., 2015, 137, 7302ꢀ7305.
D. J. Darensbourg, A. I. Moncada, W. Choi and J. H.
Reibenspies, J. Am. Chem. Soc., 2008, 130, 6523ꢀ6533.
L. Aurelio, R. T. C. Brownlee and A. B. Hughes, Chem. Rev.
2004, 104, 5823ꢀ5846.
C. W. Y. Chung and P. H. Toy, Tetrahedron: Asymmetry
2004, 15, 387ꢀ399.
T. A. Mukhtar and G. D. Wright, Chem. Rev., 2005, 105,
6
7
8
9
,
,
28 (
999ꢀ1002; (
Dalton Trans., 1989, 1483ꢀ1489.
29 ( ) T. Ema, Y. Miyazaki, S. Koyama, Y. Yano, T. Sakai,
Chem. Commun., 2012, 48, 4489ꢀ4491; ( ) T. Ema, Y.
a
) A. Tézé and G. Hervé, J. Inorg. Nucl. Chem., 1977, 39,
b
) D. E. Katsoulis and M. T. Pope, J. Chem. Soc.,
a
b
529ꢀ542.
Miyazaki, J. Shimonishi, C. Maeda, J.ꢀy. Hasegawa, J. Am.
Chem. Soc., 2014, 136, 15270ꢀ15279.
10 L. E. Overman and T. P. Remarchuk, J. Am. Chem. Soc.
2002, 124, 12ꢀ13.
11 Y. Fukata, K. Asano and S. Matsubara, J. Am. Chem. Soc.
2013, 135, 12160ꢀ12163.
,
,
30 (
a) C. P. Pradeep, D.ꢀL. Long, G. N. Newton, Y.ꢀF. Song and
L. Cronin, Angew. Chem., Int. Ed., 2008, 47, 4388ꢀ4391; (
b
)
T. Akutagawa, F. Kudo, R. Tsunashima, S.ꢀi. Noro, L. Cronin
12 (
B.ꢀX. Han, Angew. Chem., Int. Ed., 2015, 54, 5399ꢀ5403; (
A. W. Miller and S. T. Nguyen, Org. Lett., 2004, 6, 2301ꢀ
2304; ( ) Z.ꢀZ. Yang, Y.ꢀN. Li, Y.ꢀY. Wei and L.ꢀN. He,
Green Chem., 2011, 13, 2351ꢀ2353; ( ) R. Juarez, P.
Concepcion, A. Corma and H. Garcia, Chem. Commun., 2010,
46, 4181ꢀ4183; ( ) Q.ꢀW. Song, B. Yu, X.ꢀD. Li, R. Ma, Z.ꢀF.
a) J.ꢀY. Hu, J. Ma, Q.ꢀG. Zhu, Z.ꢀF. Zhang, C.ꢀY. Wu and
and T. Nakamura, Inorg. Chem., 2011, 50, 6711ꢀ6718.
b
)
31 (
2015, 17, 474ꢀ479; (
Angew. Chem., Int. Ed., 2012, 51, 6700ꢀ6703.
a) C.ꢀX. Guo, B. Yu, J.ꢀN. Xie and L.ꢀN. He, Green Chem.
,
b
) T. Kimura, K. Kamata and N. Mizuno,
c
d
32 W.ꢀJ. Yoo and C.ꢀJ. Li, Adv. Synth. Catal., 2008, 350, 1503ꢀ
1506.
e
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Green Chemistry
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DOI: 10.1039/C5GC02311D
Cu(II)-substituted polyoxometalate-based ionic liquids were successfully developed
as halogen-free bifunctional catalysts for carboxylative cyclization of atmospheric
CO2 with propargylic amines.