Bifunctional one-component catalysts for the addition of carbon dioxide to epoxides

Article abstract of DOI:10.1002/cctc.201402816

Several bifunctional ammonium salts were synthesized and employed as one-component catalysts for the conversion of CO₂ and epoxides to produce cyclic carbonates. These catalysts show superior activities compared to their monofunctional analogs. A turnover number of up to 693 and a turnover frequency of up 392h^-1 could be achieved for the best catalyst. Moreover, the effect of various solvents has been studied. All employed solvents and the product formed had a negative influence on substrate conversion. The scope and limitation of the reaction has been studied carefully for two general reaction protocols at 45 and 90-°C. In over 20 examples, the isolated yields after filtration were 90-%. In addition, we present the first organocatalyzed synthesis of a cyclohexene-based naturally occurring cyclic carbonate, and its molecular structure was determined by XRD. Furthermore, we demonstrate that the reaction can be performed even on a multigram scale and can be monitored by insitu FTIR spectroscopy. Couple up: Recyclable bifunctional ammonium salts are identified as one-component catalysts for the 100-% atom-economic coupling reaction of CO₂ and epoxides even at 45-°C. The alcohol moiety that donates a hydrogen bond accelerates the catalytic reaction remarkably. This metal and solvent-free process can be performed on a multigram scale and is applied to the synthesis of a naturally occurring cyclic carbonate.

Full text of DOI:10.1002/cctc.201402816

CHEMCATCHEM
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DOI: 10.1002/cctc.201402816
Bifunctional One-Component Catalysts for the Addition of
Carbon Dioxide to Epoxides
[
a]
Hendrik Bꢀttner, Kornelia Lau, Anke Spannenberg, and Thomas Werner*
Several bifunctional ammonium salts were synthesized and
employed as one-component catalysts for the conversion of
reaction has been studied carefully for two general reaction
protocols at 45 and 908C. In over 20 examples, the isolated
yields after filtration were 90%. In addition, we present the
first organocatalyzed synthesis of a cyclohexene-based natural-
ly occurring cyclic carbonate, and its molecular structure was
determined by XRD. Furthermore, we demonstrate that the re-
action can be performed even on a multigram scale and can
be monitored by in situ FTIR spectroscopy.
CO and epoxides to produce cyclic carbonates. These catalysts
2
show superior activities compared to their monofunctional an-
alogs. A turnover number of up to 693 and a turnover frequen-
À1
cy of up 392 h could be achieved for the best catalyst. More-
over, the effect of various solvents has been studied. All em-
ployed solvents and the product formed had a negative influ-
ence on substrate conversion. The scope and limitation of the
Introduction
The anthropogenic emission of greenhouse gases is connected
this context there have been several reports on the synergistic
effects of catalytic systems that contain a halide and an elec-
trophile. Particularly, in the presence of hydrogen-bond donors
closely to global climate change. Besides water, CO is by far
2
the largest part of the anthropogenic emission into the atmos-
[12]
[13]
[14]
[15]
phere. The chemical fixation of CO into valuable products has
such as alcohols,
phenols, carboxylic acids,
silanols,
2
[
1]
[16]
[17]
[18]
[19]
attracted much attention in recent years. CO can be utilized
chitosan,
cellulose,
b-cyclodextrin,
amino acids,
and
2
[20]
as an inexpensive, nontoxic, nonflammable, readily available,
abundant, and renewable C1 feedstock. The 100% atom-effi-
amino alcohols the addition of CO and epoxides to the cor-
2
responding cyclic carbonate was accelerated significantly.
[20a,21]
cient addition of CO and epoxides is well known and produ-
Based on our current efforts
toward the utilization of CO2
2
ces five-membered cyclic carbonates and polycarbonates, re-
as a C1 building block in the synthesis of cyclic carbonates, we
were interested to develop an active one-component catalyst.
Herein, we report the synthesis of bifunctional organocatalysts
based on an ammonium salt that bears an alcohol moiety in
the side chain. This represents a one-component catalyst that
shows a dual mode of activation. These catalysts produce
cyclic carbonates selectively under solvent-free conditions
even at 458C and on a multigram scale.
[
2]
spectively. Cyclic carbonates serve as green solvents and
have some outstanding properties such as a high boiling point
[
3]
and are odorless and low in toxicity. In addition, there are
several applications with commercial significance for cyclic car-
[
4]
bonates such as electrolytes in lithium batteries, as mono-
[
5]
mers in polymerization reactions, and as intermediates in the
[
6]
synthesis of fine chemicals. Although the synthesis of cyclic
carbonates from CO and oxiranes has been studied extensive-
2
ly, it is still a continuous challenge to develop active, readily
available, tunable, nontoxic, and selective catalytic systems.
Results and Discussion
[
7]
Commonly, Lewis acidic metal complexes and alkali metal
[
8]
[9]
[10]
The bifunctional organocatalysts were prepared easily by the
simple alkylation of amines 1 with haloalcohols 2 (Scheme 1).
The bench-stable bifunctional ammonium salts 3 were ob-
tained in a modular synthesis. The substituent R, the halide X,
and the distance between the alcohol moiety and the nitrogen
center could be varied easily by changing the amine 1 and al-
cohol 2 employed.
halides as well as imidazolium, phosphonium, and espe-
[
11]
cially ammonium salts have been employed. Usually, the ho-
mogeneous metal-based systems utilized are binary or two-
component (2 K) catalytic systems that comprise a catalyst and
[
2]
an additive/cocatalyst. In contrast, catalysts based on onium
salts are often one-component systems. However, catalytic ac-
tivity might be increased by the addition of a cocatalyst. In
[
a] H. Bꢀttner, K. Lau, Dr. A. Spannenberg, Dr. T. Werner
Leibniz-Institut fꢀr Katalyse e. V. an der Universitꢁt Rostock
Albert-Einstein-Straße 29a, 18059 Rostock (Germany)
Fax: (+49)381-1281-51326
E-mail: thomas.werner@catalysis.de
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/cctc.201402816.
Scheme 1. Synthesis of bifunctional ammonium salts 3.
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(
2-hydroxyethyl) ammonium salts 3h–j with chloride, bromide,
Table 1. Model reaction and screening results for catalysts 3 and 6.
and iodide counterions (entries 8–10). In comparison with their
ethyl-substituted equivalents, every butyl ammonium salt 3h–j
showed a higher catalytic activity. Amongst these, the iodide
organocatalyst 3j was the most active with a turnover number
(
TON) of 48, which provided quantitative conversion to 1,2-bu-
[
b]
Entry
1
Catalyst
Yield 5a [%]
TON
tylene carbonate (5a) with 96% yield (Entry 10). With regard to
the cation, the yield increased with the increasing steric de-
mands of the ammonium center. This could be either ex-
plained by the stronger nucleophilicity of the halide as the
electrostatic interaction of halide and ammonium center de-
creased with the bulkiness of the cation or simply by the in-
[
c]
3a
0
0
[
c]
2
3
4
5
6
7
8
9
3b
0
0
0
0
[
c]
3c
[22]
creasing solubility of the salt. Another crucial parameter was
the distance between the nitrogen center and the alcohol
moiety. If the chain that bears the alcohol function was extend-
ed to propyl in catalyst 3k, the yield decreased to 81% 5a
[
c]
3d
3e
3 f
0
0
0
0
(
entry 11). To emphasize the catalytic activity of the bifunction-
al ammonium catalysts 3, we tested simple monofunctional
ammonium salts 6a–c under the model reaction conditions
(entries 13–15). However, tetra-n-butyl ammonium salts 6a–
c revealed only fair yields of 5a up to 51%, which depended
significantly on the halide. The yield increased considerably
3
2
[
c]
3g
3h
3i
67
53
80
96
81
34
29
41
48
41
[
d]
À
À
À
from I to Br to Cl and followed the order of nucleophilicity.
Similar trends were observed if simple tetra-n-butyl phosphoni-
[
21b]
um salts were present as catalysts.
If bifunctional organoca-
À
À
À
10
3j
talysts 3 were employed, the order changes to Cl <Br <I ,
which can be explained by the stronger hydrogen bond inter-
actions of the alcohol moiety and the chloride compared to
that of the bromide and iodide. Notably, no product 5a was
observed in the absence of catalyst. The organocatalyst 3j was
identified as the most active catalyst and was chosen to opti-
mize the reaction conditions (Table 2).
11
3k
[
c,e]
12
13
14
15
[Bu
[Bu
[Bu
–
4
N]Cl
4
N]Br
4
N]I
6a
6b
51
24
19
0
27
12
10
0
[
c]
[
c]
6c
–
[
a] Yields were determined by GC with n-hexadecane as the internal stan-
Initially, the reaction time and its effect on the yield of cyclic
carbonate 5a were evaluated (Table 2, entries 1–3). A moderate
dard; [b] Average TON; [c] Catalysts were commercially available and
used as purchased; [d] 1.8 mol% catalyst; [e] 1.9 mol% catalyst.
Table 2. Optimization of reaction conditions with bifunctional organoca-
talyst 3j.
The conversion of 1,2-epoxybutane (4a) with CO to pro-
2
duce 1,2-butylene carbonate (5a) was chosen as a model reac-
tion to evaluate the bifunctional organocatalysts 3 (Table 1).
Often the addition of CO to epoxides is performed at reaction
2
temperatures ꢀ1008C and CO2 pressures ꢀ2.0 MPa if one-
[
2,3]
component catalysts are utilized. As our aim was to develop
catalysts that show high activities under mild conditions, we
[
c]
Entry Amount of 3j
mol%]
T
p(CO
2
)
t [h] Yield of 5a TON
TOF
À1
[
[8C] [MPa]
[%]
[h
]
performed our screening experiments at an initial CO pressure
2
of p(CO )=1.0 MPa at 908C.
1
2
3
4
5
6
7
8
1.9
2.0
2.0
5.0
2.2
2.4
2.3
2.0
2.0
2.0
0.1
0.1
90 1.0
90 1.0
90 1.0
45 1.0
60 1.0
80 1.0
100 1.0
90 0.2
90 0.5
90 2.0
150 2.0
150 2.0
0.5
1.0
2
68
88
96
89
44
87
>99
51
96
99
36
44
48
18
20
36
45
25
48
73
2
44
24
1
In the presence of 2-(hydroxyethyl)- and (carboxymethyl)tri-
methylammonium salts 3a–d and the triethylamine-based am-
monium salt 3e, no catalytic activity was observed (Table 1, en-
tries 1–5). The bromide catalyst 3 f showed only a slight con-
version to the desired product 5a (entry 6). This is remarkable
as choline-based catalysts have been utilized previously under
[b]
18
2
2
2
2
2
2
1
2
10
18
23
13
24
25
392
347
9
10
11
[
12e,14b]
harsh conditions or in the presence of a solvent.
Howev-
50
392
693
[
[
b]
b]
er, ammonium iodide 3g emphasized the impact of halides for
catalytic activity. Chloride and bromide salts 3e and 3 f
showed nearly no conversion, whereas catalyst 3g led to
a yield of 67% of cyclic carbonate 5a (entry 7). To further in-
vestigate the impact of the cation center, we tested tri-n-butyl-
39
69
1
2
[a] Yields were determined by GC with n-hexadecane as the internal stan-
dard; [b] Isolated yield; [c] Average TON and TOF for the corresponding
reaction time.
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yield of 68% on 5a was observed just after 0.5 h (entry 1). Nev-
ertheless, a reaction time of 2 h was necessary to obtain 96%
of 5a and full conversion of 4a (entry 3). Under the mild reac-
Table 4. Coupling reaction of CO
of bifunctional organocatalyst 3j.
2
and various epoxides 4 in the presence
[
13a]
tion conditions reported previously by Kleij et al.,
5a was
isolated in 89% yield by utilizing 5 mol% of 3j. The reaction
temperature had a significant effect on the yield of 5a (en-
tries 5–7). Reducing the temperature from 90 (entry 3) to 608C
caused a decrease of the yield of 5a to 44% (entry 4). Increas-
ing the temperature to 808C resulted in 87% of 5a, whereas
at 1008C >99% yield of 5a was obtained (entries 6–7). With
Entry
Product
Yield [%]
[
a]
[b]
908C
458C
regard to the impact of CO pressure, we varied the pressure
2
[
c]
1
2
3
4
5a
5b
5c
5d
91
92
95
95
89 (61 )
from 0.2 to 2.0 MPa (entries 8–10). At 0.2 MPa a significant de-
cline of the yield was observed, whereas a pressure of
ꢀ
0.5 MPa provided an excellent yield >96% of 5a. Notably,
>99
the reaction time and catalyst amount can be reduced (en-
À1
tries 11–12) to reach a TON up to 693 and a TOF of 347 h .
However, to retain good conversion and yield, higher reaction
temperatures are required.
93
89
In addition, the influence of several solvents was investigat-
ed at 908C, p(CO )=1.0 MPa, 1 h, and 2 mol% of 3j (Table 3).
2
[
a]
Table 3. Variation of solvents for the model reaction with catalyst 3j.
5
6
5e
5 f
94
93
98
99
Entry
Solvent
Yield of 5a [%]
1
2
3
4
5
6
7
8
9
–
66
17
45
46
32
3
MeOH
EtOH
n-butanol
tert-amyl alcohol
7
5g
93
93
CH
CH
2
Cl
CN
2
3
5
THF
1,4-dioxane
methyl ethyl ketone
1,2-butylene carbonate (5a)
37
20
38
–
[d]
8
9
5h
5i
9 (71
)
12
99
10
11
99
[
a] Reaction conditions: 1.0m 4a, 2 mol% 3j, 908C, p(CO
2
)=1.0 MPa,
1.0 h, n-hexadecane as the internal standard.
1
0
5j
5k
5l
94
90
91
94
90
99
Under neat conditions, a yield of 66% of 5a was obtained.
However, under these conditions, none of the employed sol-
11
vents led to an enhancement of the yield of 5a. Surprisingly, if
5
a was applied as solvent no reaction was observed (entry 11).
12
This experiment indicated a product inhibition for the catalytic
coupling reaction of epoxide 4a and CO if the bifunctional
2
catalyst 3j was employed.
In accordance with these experiments, the substrate scope
was evaluated under the optimized reaction conditions of
1
3
4
5m
5n
92
20
>99
9
08C, p(CO )=0.5 MPa, 2 h, 2 mol% 3j, and solvent-free condi-
2
[
e]
1
tions (Table 4). Terminal alkyl carbonates 5a–c and the aromat-
ic substituted carbonates 5d–e were obtained in excellent
yields (entries 1–5). A yield of 93% each for epichlorohydrin
[
[
1
a] Reaction conditions: 2 mol% 3j, 908C, p(CO
b] 5 mol% 3j, 458C, p(CO )=1.0 MPa 18 h; [c] 2 mol% 3j, 458C, p(CO
.0 MPa 18 h; [d] 2 mol% 3j, p(CO )=4.0 MPa, 1208C, 4 h; [e] 1008C,
)=5.0 MPa, yield determined by GC with n-hexadecane as the
2
)=0.5 MPa, 2 h;
(
4 f) and 1,2-epoxy-5-hexene (4g) demonstrate the high selec-
tivity in the presence of different functional groups (entries 6–
). The internal carbonate 5h was only obtained in a poor
yield of 9% (entry 7). Cyclohexene oxide (4h) is known to be
2
2
)=
2
7
16 h, p(CO
2
internal standard.
[14b,23]
a challenging substrate because of its steric hindrance.
The reaction was performed under harsher conditions of
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1
208C, p(CO )=4.0 MPa, and 4 h to give 71% of the desired
2
product 5h. Finally, we tested glycidyl ether and ester deriva-
tives 4i–m (entries 9–13). The corresponding products were
obtained in excellent yields, and even methyl methacrylate
substituted carbonate 5m, which is quite reactive towards
polymerization side reactions, was isolated in 92% yield. Epoxi-
dized methyl oleate 4n was also tested under our standard re-
action conditions for the synthesis of oleochemical carbonates
(entry 14). However, only a poor yield of 20% of the corre-
sponding cyclic carbonate 5n with a cis/trans ratio of 48:52
was determined. In all reactions, the cyclic carbonate was
formed exclusively and no side products were observed. Nota-
bly, the catalyst can be removed easily by filtration over SiO2
to obtain analytically pure carbonates 5. For substrates prone
to polymerization, for example, 4g and 4m, milder reaction
Figure 1. ORTEP view of the molecular structure of 5o (displacement ellip-
soids are drawn at the 30% probability level).
[
29]
[
24]
conditions might be of particular interest. Hence, we per-
formed the reaction at 458C. Although some further adjust-
ments with regard to the reaction conditions had to be made
to obtain comparable results, in some cases even higher yields
could be obtained (entries 2, 5, 6, 12, and 13). In this context,
the conversion of 4m to 5m is noteworthy as the isolated
yield for this potential polymeric building block increased from
92 to >99%, which indicates perfect chemoselectivity.
The structural motif of five-membered cyclic carbonates 5
[
25]
also appears in natural products. The cyclohexene-based car-
bonate 5o represents the simplest example of organic carbo-
nates from natural sources. This was identified in the crystal
structure of the Aureobacterium species (À)-g-lactamase, which
[26]
is assumed to originate from the host cell of Escherichia coli.
Kleij et al. were able to synthesize 5o in 73% yield with a cis/
trans ratio of 95:5 by employing an Al complex based on the
[27]
Scheme 3. Putative reaction mechanism for the coupling reaction of CO
and 4a over bifunctional organocatalyst 3j.
2
aminotriphenolate ligand with [NBu ]Br as the cocatalyst. Re-
4
[
28a]
[28b]
cently, Williams et al.
and Darensbourg et al.
prepared
polymers derived from the copolymerization of cyclohexene
oxide, 4o, and CO . We prepared cis-5o from the correspond-
ing epoxide in the presence of bifunctional organocatalyst 3j
Finally, an intramolecular substitution reaction produces 5a
under the liberation of the catalyst 3j.
2
(Scheme 2). To the best of our knowledge, this is the first orga-
Additionally, we were interested to scale up the coupling re-
nocatalyzed synthesis of 5o that utilizes CO as a C1 building
block.
action of CO and 4a with the bifunctional organocatalyst 3j.
Hence, a 100 cm steel autoclave was equipped with 36.0 g of
2
2
3
4
a and an attenuated total reflectance (ATR) FTIR spectroscopy
fiber probe to monitor the time-dependent course of reaction.
From the beginning of the reaction, the intensity of specific
cyclic carbonate bands at n˜ 1787 (C=O carbonate stretching
À1
band), 1164, and 1051 cm
increased tremendously and
reached their maxima after 160 min (Figure 2). With regard to
the substrate, the intensity of the epoxide vibration bands at
Scheme 2. Organocatalyzed synthesis of organic carbonate 5o.
À1
[31]
n˜ 902 and 831 cm (epoxide ring deformation bands)
de-
creased continuously until they reached a minimum after
160 min. Under these conditions a yield of 96% of 5a was iso-
lated, which corresponds to 55.7 g of 5a.
Finally, we examined the reusability of catalyst 3j under the
optimized reaction conditions. We were able to run at least six
cycles with 3j and obtained 96% of 5a in each of the first two
runs and 93% in the third cycle (Figure 3). After the fourth
cycle, the yield decreased slightly to 89% of 5a. In the sixth
cycle, a yield of 72% of 5a was still isolated. The product 5a
was removed by Kugelrohr distillation after every cycle. Finally,
Notably, only the cis isomer of 5o, confirmed by XRD, was
formed in 47% yield which confirms the high selectivity of cat-
alyst 3j (Figure 1).
In accordance with previous reports and based on our ex-
periments, a plausible mechanism proceeds in three steps
[
11e,13c,30]
(Scheme 3).
The epoxide 4a is activated by the hydro-
gen bonding of the catalyst (A). A nucleophilic substitution re-
action of the iodide forms an alcoholate (B). Nucleophilic addi-
tion of the alcoholate to CO forms the acyclic carbonate (C).
2
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carbonate (5a). The time-dependent course of the reaction
was monitored by in situ attenuated total reflectance FTIR
spectroscopy. The reusability of the catalyst 3j in the model re-
action was examined in six consecutive cycles. In the first four
runs, excellent yields up to 96% of 5a were obtained, and
after the sixth run a still good yield of 72% was isolated.
Experimental Section
All epoxides and commercially available catalysts were purchased
from Sigma Aldrich, Acros, or ABCR and used as received with no
further purification. CO (99.998%) was obtained from Linde AG.
2
2
Figure 2. Conversion of 4a with CO followed by in situ ATR FTIR spectros-
The conversion and yield were analyzed by GC by using an Agilent
7890A GC system and n-hexadecane as the internal standard. NMR
spectra were measured by using Bruker AV 300 and Bruker AV 400
spectrometers and referred to the residual signals of the deuterat-
ed solvents. IR spectra were recorded by using a Nicolet iS10 MIR
from Thermo Fisher Scientific. XRD data were collected by using
a Bruker Kappa APEX II Duo diffractometer. The structure was
solved by direct methods and refined by full-matrix least-squares
À1
copy. Reaction conditions: 2 mol% 3j, 908C, p(CO
2
)=1.0 MPa, a=1787 cm
À1
À1
(C=O carbonate stretching band), b=902 cm c=831 cm (epoxide ring
deformation bands).
2
[32]
procedures on F by using the SHELXTL software package XP.
Bruker AXS was used for graphical representation. In situ experi-
ments were conducted by using a fiber probe from Infrared Fiber
Sensors and Harrick FiberMate 2. Stainless-steel autoclaves from
Parr Instruments were used for high-pressure experiments.
General procedures
Preparation of bifunctional catalysts (GP1)
The bifunctional ammonium salts 3 were prepared by heating the
amine 1 and halohydrin 2 to 80–1208C for 16–24 h. The crude
product was washed with diethyl ether and dried under reduced
pressure at an appropriate temperature.
Figure 3. Isolated yields of 5a from recycled catalyst 3j.
catalyst 3j was analyzed. Not only 3j but also the decomposi-
tion product tri-n-butylamine were observed by NMR spectros-
copy and GC–MS, which was presumably formed as a result of
thermal stress under the distillation conditions.
Catalyst and parameter screening (GP2)
The reactor was charged with catalyst 3 or 6 (0.1–2.0 mol%) and
4
a (2.00 g, 27.7 mmol). The autoclave was sealed and charged
with 0.2–2.0 MPa CO at 238C until equilibrium was reached. Then
the reaction mixture was heated to 45–1508C and stirred for 0.5–
8.0 h. The reactor was cooled to ambient temperature, and CO2
Conclusions
2
Several bifunctional organocatalysts 3 based on ammonium
1
salts were prepared and tested in the conversion of CO with
was released slowly. The reaction mixture was analyzed by GC. The
conversion of 4a and the yield of 5a were determined using inter-
nal standard n-hexadecane.
2
1,2-butylene oxide (4a). They represent very efficient one-com-
ponent catalysts. The catalyst activity is influenced significantly
by the substituents at the nitrogen center and the halide. The
synergistic effect of the catalyst revealed a superior catalytic
activity compared to simple tetra-n-butyl ammonium salts 6,
Coupling reaction of CO and epoxide at 908C (GP3)
2
À1
Typically, the autoclave was charged with 0.02 equiv. of catalyst 3j
and 1.00 equiv. of epoxide 4. The reactor was purged once with
CO , pressurized with CO to 0.5 MPa, heated to 908C, and stirred
and a turnover frequency up to 347 h could be achieved for
catalyst 3 f. In the presence of the most active ammonium salt
2
2
3
j, several epoxides were converted under mild reaction condi-
for 2 h. Subsequently, the reactor was cooled to ambient tempera-
tions of 908C and p(CO )=0.5 MPa within 2 h under solvent-
2
ture with an ice bath, and CO was released slowly. The reaction
2
free conditions. The corresponding products were obtained in
excellent yields and could be isolated easily by filtration over
silica gel and subsequent distillation if necessary. Similar or
even better results were achieved under modified conditions
at 458C. The natural product 5o was obtained in 47% yield in
mixture was filtered over SiO (CH Cl ), and the volatiles were re-
moved under reduced pressure.
2
2
2
Coupling reaction of CO and epoxide at 458C (GP4)
2
1
00% cis selectivity if the organocatalyst 3j was employed.
Typically, the autoclave was charged with 0.05 equiv. of catalyst 3j
and 1.00 equiv. of epoxide 4. The reactor was purged once with
CO , pressurized with CO to 1.0 MPa, heated to 458C, and stirred
Furthermore, the catalyst 3j was employed in a multigram ex-
periment to obtain 55.7 g of the coupling product 1,2-butylene
2
2
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2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemCatChem 0000, 00, 1 – 10
&
5
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ÞÞ
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for 18 h. Subsequently, the reactor was cooled to ambient temper-
Tri-n-butyl-(2-hydroxyethyl)ammonium iodide (3j)
ature with an ice bath, and CO was released slowly. The reaction
2
According to GP1, tri-n-butylamine (1.77 g, 9.57 mmol) and 2-io-
doethanol (1.59 g, 9.23 mmol) were stirred for 24 h at 808C. The
product 3j was obtained as a pale yellow solid (2.79 g, 7.81 mmol,
mixture was filtered over SiO (CH Cl ), and the volatiles were re-
2
2
2
moved under reduced pressure.
1
3
8
1
5%). H NMR (300 MHz, CDCl ): d=1.03 (t, J=7.3 Hz, 9H), 1.40–
3
3
.52 (m, 6H), 1.64–1.75 (m, 6H), 3.39–3.44 (m, 6H), 3.59 (t, J=
3
Synthesis and characterization of bifunctional ammonium
salts 3
4.7 Hz, 2H), 4.14–4.18 (m, 2H), 4.47 ppm (t, J=6.1 Hz, 1H, OH);
13
1
C{ H} NMR (75 MHz, CDCl ): d=13.65 (3ꢂCH ), 19.65 (3ꢂCH ),
3
3
2
2
4.06 (3ꢂCH ), 55.23 (CH ), 59.63 (3ꢂCH ), 60.49 ppm (CH ); IR
2 2 2 2
[33]
Triethyl-(2-hydroxyethyl)ammonium chloride (3e)
(ATR): n˜ =3315 (br. s), 2960 (s), 2873 (m), 1465 (m), 1380 (w), 1087
À1
(
m), 907 (m), 737 cm
(w); HRMS (ESI-TOF): m/z: calcd for
According to GP1, a solution of triethylamine (1.08 g, 10.7 mmol)
in toluene (2.6m, 4 mL), and 2-chloroethanol (1.35 g, 16.8 mmol)
were stirred for 24 h at 1008C. The product 3e was obtained as
+
C H NO: 230.2478 [M ÀI]; found: 230.2477.
14
32
1
a colorless solid (926 mg, 5.11 mmol, 48%). m.p.: 1088C; H NMR
Tri-n-butyl-(3-hydroxypropyl)ammonium iodide (3k)
3
3
(
300 MHz, D O): d=1.26 (tt, J=7.3 Hz, 1.5 Hz, 9H), 3.36 (q, J=
2
3
7
.3 Hz, 6H), 3.37 (t, J=5.5 Hz, 2H), 3.94–3.98 ppm (m, 2H);
C{ H} NMR (75 MHz, D O): d=6.64 (3ꢂCH ), 53.33 (2ꢂCH ), 54.74
According to GP1, tri-n-butylamine (1.48 g, 7.98 mmol) and 3-iodo-
propanol (940 mg, 5.07 mmol) were stirred for 24 h at 1008C. The
product 3k was dried in vacuo for 4 h at 1008C and was obtained
1
3
1
2
3
2
(
1
2ꢂCH ), 57.38 ppm (CH ); HRMS (ESI-TOF): m/z: calcd for C H NO:
2 2 8 20
+
1
46.1539 [M ÀCl]; found: 146.1544; IR (ATR): n˜ =3212 (br. s), 2977
as a brown solid (1.80 g, 4.84 mmol, 96%). H NMR (300 MHz,
À1
3
(
w), 2677 (w), 1082 (s), 1000 (s), 784 cm (s).
CDCl ): d=0.97 (t, J=7.3 Hz, 9H), 1.35–1.47 (m, 6H), 1.60–1.72 (m,
3
6
3
H), 1.95–2.00 (m, 2H), 3.22–3.27 (m, 6H), 3.48–3.54 (m, 2H), 3.70–
13
1
.75 (m, 2H), 3.79–3.83 ppm (m, 1H); C{ H} NMR (75 MHz, CDCl ):
3
d=13.57 (3ꢂCH ), 19.60 (3ꢂCH ), 23.95 (3ꢂCH ), 25.42 (CH ), 52.41
[
34]
3
2
2
2
Triethyl-(2-hydroxyethyl)ammonium bromide (3 f)
(
CH ), 57.69 (CH ), 58.98 ppm (3ꢂCH ); HRMS (ESI-TOF): m/z: calcd
2
2
2
+
for C H NO: 244.2635 [M ÀI]; found: 244.2640; elemental analysis
According to GP1, triethylamine (2.21 g, 21.8 mmol) and 2-bromo-
ethanol (2.77 g, 22.2 mmol) were stirred for 16 h at 1208C. The
product 3 f (4.14 g, 18.3 mmol, 84%) was dried 6 h at 1008C in va-
cuo and obtained as a colorless solid. H NMR (300 MHz, D O): d=
.28 (tt, J=7.3 Hz, 1.5 Hz, 9H), 3.33–3.41 (m, 8H), 3.95–4.00 ppm
m, 2H); C{ H} NMR (75 MHz, D O): d=6.70 (3ꢂCH ), 53.39 (2ꢂ
2 3
15 34
calcd (%) for C H INO (371.34): C 48.52, H 9.23, N 3.77, I 34.17;
15 34
found: C 48.38, H 9.06, N 3.96, I 34.03.
1
2
3
1
1
3
1
Synthesis and characterization of cyclic carbonates 5
(
CH ), 54.77 (2ꢂCH ), 57.41 ppm (CH ); HRMS (ESI-TOF): m/z: calcd
[36]
2
2
2
4
-Ethyl-1,3-dioxolan-2-one (5a)
+
for C H NO: 146.1539 [M ÀBr]; found: 146.1539; IR (ATR): n˜ =3214
8
20
À1
(
br. s), 2977 (w), 2675 (w), 1080 (s), 999 (s), 782 cm (s).
According to GP3, butylene oxide (4a, 1.99 g, 27.6 mmol) and CO2
were converted to the corresponding carbonate 5a in the pres-
ence of 3j (200 mg, 0.560 mmol). The product 5a was obtained as
colorless oil (2.91 g, 25.1 mmol, 91%). According to GP4, butylene
Tri-n-butyl-(2-hydroxyethyl)ammonium chloride (3h)
oxide (4a, 1.80 g, 25.0 mmol) and CO were converted to the corre-
2
sponding carbonate 5a in the presence of 3j (445 mg, 1.25 mmol).
The product 5a was obtained as colorless oil (2.59 g, 22.3 mmol,
According to GP1, tri-n-butylamine (6.97 mg, 37.6 mmol) and 2-
chloroethanol (3.07 g, 38.6 mmol) were stirred for 24 h at 808C.
The product 3h was dried in vacuo at 708C and was obtained as
8
9%). A 100 mL stainless-steel reactor equipped with an ATR FTIR
1
fiber probe was charged with butylene oxide (4a, 36.0 g,
500 mmol), 3j (3.01 g, 8.41 mmol) and 10 bar CO2. The reaction
a colorless solid (1.21 g, 4.54 mmol, 10%). m.p.: 638C; H NMR
3
(
300 MHz, CDCl ): d=1.01 (t, J=7.4 Hz, 9H), 1.37–1.50 (m, 6H),
3
mixture was stirred for 6 h at 908C and CO pressure was kept con-
1
.62–1.73 (m, 6H), 3.39–3.44 (m, 6H), 3.52–3.55 (m, 2H), 4.07–4.12
2
3
13
1
stant. Afterwards the autoclave was cooled down with an ice bath
and vented slowly. The crude product was filtered through silica
(
m, 2H), 6.25 ppm (t, J=6.1 Hz, 1H, OH); C{ H} NMR (75 MHz,
CDCl ): d=13.61 (3ꢂCH ), 19.66 (3ꢂCH ), 23.92 (3ꢂCH ), 55.54
3
3
2
2
gel and volatiles were removed in vacuo. The product 5a was ob-
(
(
CH ), 59.40 (3ꢂCH ), 60.77 ppm (CH ); IR (ATR): n˜ =3165 (s), 2960
2 2 2
1
À1
tained as
a
colorless oil (55.7 g, 480 mmol, 96%). H NMR
s), 2873 (m), 1456 (s), 1094 (m), 705 cm (s); HRMS (ESI-TOF): m/z:
+
(300 MHz, CDCl ): d=1.04 (t, J=7.5 Hz, 3H), 1.73–1.86 (m, 2H),
3
calcd for C H NO: 230.2478 [M ÀCl]; found: 230.2480.
1
4
32
4
4
.09 (dd, J=8.4, 7.0 Hz, 1H), 4.50–4.55 (dd, J=7.9 Hz, 7.9 Hz, 1H),
13
1
.62–4.72 ppm (m, 1H); C{ H} NMR (75 MHz, CDCl ): d=8.46
3
(
CH ), 26.92 (CH ), 68.97 (CH), 77.95 (CH ), 155.06 ppm (C=O); MS
3
2
2
[35]
+
+
Tri-n-butyl-(2-hydroxyethyl)ammonium bromide (3i)
(EI, 70 eV): m/z (%): 116 (3) [M ], 87 (100) [C H O ], 86 (22), 57 (22)
3 3 3
+
[C4H9 ].
According to GP1, tri-n-butylamine (6.97 mg, 37.6 mmol) and 2-
bromoethanol (3.03 g, 37.6 mmol) were stirred for 24 h at 808C.
The product 3i was dried in vacuo for 1 h at 708C and was ob-
[36]
4
-Methyl-1,3-dioxolan-2-one (5b)
1
tained as a colorless solid (3.51 g, 11.3 mmol, 49%). H NMR
3
(
300 MHz, CDCl ): d=0.96 (t, J=7.4 Hz, 9H), 1.33–1.45 (m, 6H),
According to GP3, propylene oxide (4b, 1.00 g, 17.3 mmol) and
CO2 were converted to the corresponding carbonate 5b in the
presence of 3j (310 mg, 0.867 mmol). The product 5b was ob-
tained as a colorless oil (1.76 g, 17.2 mmol, >99%). According to
3
1
.60–1.70 (m, 6H), 3.35–3.40 (m, 6H), 3.53–3.56 (m, 2H), 4.01–4.06
3
13
1
(
m, 2H), 5.20 ppm (t, J=6.0 Hz, 1H, OH); C{ H} NMR (75 MHz,
CDCl ): d=13.54 (3ꢂCH ), 19.56 (3ꢂCH ), 23.89 (3ꢂCH ), 55.32
3
3
2
2
(
CH ), 59.43 (3ꢂCH ), 60.49 ppm (CH ); HRMS (ESI-TOF): m/z: calcd
GP4, propylene oxide (4b, 1.00 g, 17.3 mmol) and CO were con-
verted to the corresponding carbonate 5b in the presence of 3j
2
2
2
2
+
for C H NO: 230.2478 [M ÀBr]; found: 230.2481.
1
4
32
ꢁ
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemCatChem 0000, 00, 1 – 10
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(
310 mg, 0.868 mmol). The product 5b was obtained as colorless
calcd (%) for C H O (178.18): C 67.41, H 5.66; found: C 67.33, H
5.64.
10
10
3
1
oil (1.763 g, 17.3 mmol, >99%). H NMR (400 MHz, CDCl ): d=1.47
3
(
8
d, J=6.3 Hz, 3H), 4.02 (dd, J=8.4 Hz, 7.3 Hz, 1H), 4.55 (dd, J=
.1 Hz, 7.8 Hz, 1H), 4.80–4.89 ppm (m, 1H); C{ H} NMR (100 MHz,
13
1
[
36]
CDCl ): d=19.29 (CH ), 70.57 (CH ), 73.49 (CH), 154.97 ppm (C=O);
4-(Chloromethyl)-1,3-dioxolan-2-one (5 f)
3
3
2
+
+
MS (EI, 70 eV): m/z (%): 102 (5) [M ], 87 (20) [C H O ], 58 (16), 57
3
3
3
According to GP3, epichlorohydrin (4 f, 2.01 g, 21.5 mmol) and CO2
were converted to the corresponding carbonate 5 f in the presence
of 3j (160 mg, 0.448 mmol). The product 5e was obtained as a col-
orless oil (2.72 g, 19.9 mmol, 93%). According to GP4, 4 f (998 mg,
(
100).
[37]
4-Hexyl-1,3-dioxolan-2-one (5c)
1
0.8 mmol) and CO were converted to the corresponding carbon-
2
ate 5 f in the presence of 3j (193 mg, 0.540 mmol). The product 5 f
was obtained as colorless oil (1.47 g, 10.7 mmol, >99%). H NMR
According to GP3, 1,2-epoxyoctane (4c, 2.02 g, 15.7 mmol) and
CO2 were converted to the corresponding carbonate 5c in the
presence of 3j (110 mg, 0.308 mmol). The product 5c was ob-
tained as a colorless oil (2.32 g, 13.51 mmol, 86%). According to
1
(
300 MHz, CDCl ): d=3.71–3.82 (m, 2H), 4.43 (dd, J=8.9 Hz, 5.8 Hz,
3
1
H), 4.60 (dd, J=8.9 Hz, 8.2 Hz, 1H), 4.93–5.01 ppm (m, 1H);
13
1
C{ H} NMR (75 MHz, CDCl ): d=43.65 (CH ), 66.91 (CH ), 74.22
GP4, 1,2-epoxyoctane (4c, 1.01 g, 7.89 mmol) and CO were con-
3
2
2
2
+
(CH), 154.13 ppm (C=O); MS (EI, 70 eV): m/z (%): 136 (1) [M ], 87
verted to the corresponding carbonate 5c in the presence of 3j
+
(100) [C H O ], 86 (4), 62 (7), 57 (6), 51 (4); elemental analysis
(
138 mg, 0.386 mmol). The product 5c was obtained as colorless
3
3
3
1
calcd (%) for C H ClO (136.53): C 35.19, H 3.69; found: C 35.42, H
oil (1.27 g, 7.37 mmol, 93%). H NMR (300 MHz, CDCl ): d=0.89 (t,
4
5
3
3
3
.51.
J=6.8 Hz, 3H), 1.30–1.50 (m, 8H), 1.62–1.83 (m, 2H), 4.07 (dd, J=
8
.3 Hz, 7.2 Hz, 1H), 4.52 (dd, J=8.2 Hz, 8.0 Hz, 1H), 4.66–4.75 ppm
1
3
1
(
m, 1H); C{ H} NMR (100 MHz, CDCl ): d=13.93 (CH ), 22.39 (CH ),
3 3 2
[38]
4
-(But-3-enyl)-1,3-dioxolan-2-one (5g)
2
4.26 (CH ), 28.73 (CH ), 31.45 (CH ), 33.83 (CH ), 69.33 (CH ), 76.98
2 2 2 2 2
+
(
CH), 155.02 ppm (C=O); MS (EI, 70 eV): m/z (%): 97 (10) [C H ],
7 13
According to GP3, 1,2-epoxy-5-hexene (4g, 2.00 g, 19.8 mmol) and
CO2 were converted to the corresponding carbonate 5g in the
presence of 3j (140 mg, 0.392 mmol). The product 5g was ob-
tained as a yellow oil (2.62 g, 18.4 mmol, 93%). According to GP4,
+
+
9
7
5 (33), 87 (22), 85 (16), 82 (50) [C H ], 81 (100) [C H ], 71 (49),
6
10
+
9
+
9
+
0 (19), 69 (40) [C H ], 68 (67) [C H ], 67 (60) [C H7 ], 58 (79), 57
5
9
5
+
8
5
+
(
(
80) [C H ], 56 (34), 55 (80) [C H ], 54 (46), 53 (11); EA calculated
%) for C H O (172.22): C 62.77, H 9.36; found: C 62.30, H 9.25.
4
9
4
7
9
16
3
4
g (1.00 g, 10.2 mmol) and CO were converted to the correspond-
2
ing carbonate 5g in the presence of 3j (181 mg, 0.507 mmol). The
product 5g was obtained as a yellow oil (1.34 g, 9.45 mmol, 93%).
[36]
4-Phenyl-1,3-dioxolan-2-one (5d)
1
H NMR (400 MHz, CDCl ): d=1.74–1.82 (m, 1H), 1.89–1.98 (m, 1H),
3
2
8
5
3
1
.14–2.31 (m, 2H), 4.08 (dd, J=8.4 Hz, 7.2 Hz, 1H), 4.53 (dd, J=
According to GP3, styrene oxide (4d, 2.02 g, 16.4 mmol) and CO2
were converted to the corresponding carbonate 5d in the pres-
ence of 3j (120 mg, 0.336 mmol). The product 5d was obtained as
a colorless solid (2.55 g, 15.5 mmol, 95%). According to GP4, sty-
.3 Hz, 8.0 Hz, 1H), 4.69–4.77 (m, 1H), 5.04–5.12 (m, 2H), 5.74–
13
1
.84 ppm (m, 1H); C{ H} NMR (75 MHz, CDCl ): d=28.58 (CH ),
3
2
2.98 (CH ), 69.25 (CH ), 76.26 (CH), 116.35 (CH ), 136.02 (CH),
2
2
2
+
54.90 ppm (C=O); MS (EI, 70 eV): m/z (%): 83 (17) [M ÀC H O], 80
3
5
rene oxide (4d, 1.00 g, 8.33 mmol) and CO were converted to the
2
+
+
(
(
23), 79 (12), 69 (13) [C H O ], 67 (18), 57 (10) [C H O ], 56 (15), 55
4 5 3 5
75) [C H ], 54 (100) [C H ], 53 (19); elemental analysis calcd (%)
corresponding carbonate 5d in the presence of 3j (150 mg,
+
7
+
6
4
4
0
.420 mmol). The product 5d was obtained as colorless solid
1
for C H O (142.15): C 59.14, H 7.09; found: C 59.13, H 6.94.
7 10 3
(
1.22 g, 7.40 mmol, 89%). H NMR (300 MHz, CDCl ): d=4.35 (dd,
3
J=8.6 Hz, 7.4 Hz, 1H), 4.81 (dd, J=8.4 Hz, 8.4 Hz, 1H), 5.68 (dd, J=
13
1
8
.0 Hz, 7.9 Hz, 1H), 7.34–7.49 ppm (m, 5H); C{ H} NMR (75 MHz,
[37]
Hexahydrobenzo-1,3-dioxol-2-one (5h)
CDCl ): d=71.13 (CH ), 77.95 (CH), 125.83 (2ꢂCH), 129.22 (2ꢂCH),
3
2
1
1
9
29.72 (CH), 135.76 (C), 154.77 ppm (C=O); MS (EI, 70 eV): m/z (%):
In the presence of 3j (150 mg, 0.420 mmol) cyclohexene oxide (4h,
2.01 g, 20.0 mmol) and CO2 were stirred for 4.0 h at 1208C and
4.0 MPa. The crude product was filtered with CH Cl over silica gel,
+
+
+
64 (60) [M ], 119 (13) [M ÀCO ], 105 (30) [C H ], 92 (13), 91 (74),
2
8
9
+
6
+
0 (100) [C H ], 89 (37), 78 (72), 77 (26) [C H ], 65 (20), 63 (16), 51
7
6
5
2
2
+
(
25) [C H ].
4 3
and the volatiles were removed in vacuo. The product 5h was ob-
tained as a colorless solid (2.01 g, 14.2 mmol, 71%). According to
GP4, 4h (1.07 g, 10.9 mmol) and CO were converted to the corre-
sponding carbonate 5h in the presence of 3j (181 mg,
2
[13a]
4-Benzyl-1,3-dioxolan-2-one (5e)
0
.507 mmol). The product 5h was obtained as a colorless solid
According to GP3, 2-benzyloxirane (4e, 1.35 g, 10.1 mmol), and
CO2 were converted to the corresponding carbonate 5e in the
presence of 3j (70 mg, 0.20 mmol). The product 5e was obtained
as colorless oil (1.68 g, 9.44 mmol, 94%). According to GP4, 2-ben-
1
(187 mg, 1.32 mmol, 12%). H NMR (300 MHz, CDCl ): d=1.37–1.49
3
(m, 2H), 1.58–1.70 (m, 2H), 1.87–1.94 (m, 4H,), 4.66–4.72 ppm (m,
13
1
2
H); C{ H} NMR (100 MHz, CDCl ): d=19.13 (2ꢂCH ), 26.75 (2ꢂ
3 2
CH ), 75.69 (2ꢂCH), 155.30 ppm (C=O); MS (EI, 70 eV): m/z (%): 97
2
zyloxirane (4e, 941 mg, 7.02 mmol) and CO were converted to the
2
+
+
(13), 83 (36) [C H ], 80 (31), 79 (11), 70 (42), 69 (100) [C H ], 67
6 11 5 9
corresponding carbonate 5e in the presence of 3j (123 mg,
+
7
(12), 57 (52), 56 (14), 55 (88) [C H ], 54 (53), 53 (11); elemental
4
0
6
1
8
7
.344 mmol). The product 5e was obtained as colorless oil (1.23 g,
analysis calcd (%) for C H O (142.15): C 59.14, H 7.09; found: C
1
7
10
3
.90 mmol, 98%). H NMR (300 MHz, CDCl ): d=3.00 (dd, J=
3
5
8.86, H 7.09.
4.3 Hz, 6.6 Hz, 1H), 3.17 (dd, J=14.2 Hz, 6.2 Hz, 1H), 4.18 (dd, J=
.7 Hz, 7.0 Hz, 1H), 4.42–4.78 (m, 1H), 4.90–4.99 (m, 1H), 7.32–
.39 ppm (m, 5H); NMR (75 MHz, CDCl ): d=39.56 (CH ), 68.43
3
2
[11a]
4
-(Phenoxymethyl)-1,3-dioxolan-2-one (5i)
(
CH ), 76.80 (CH), 127.56 (CH), 128.97 (2ꢂCH), 129.32 (2ꢂCH),
2
1
33.84 (C), 154.73 ppm (C=O); MS (EI, 70 eV): m/z (%): 178 (19)
According to GP3, glycidyl phenyl ether (4i, 1.98 g, 13.1 mmol) and
CO2 were converted to the corresponding carbonate 5i in the
+
+
+
[M ], 92 (11), 91 (100) [C H ], 65 (10) [C H5 ]; elemental analysis
7 7 5
ꢁ
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemCatChem 0000, 00, 1 – 10
&
7
&
ÞÞ
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CHEMCATCHEM
FULL PAPERS
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presence of 3j (90 mg, 0.25 mmol). The product 5i was obtained
as a colorless solid (2.53 g, 13.0 mmol, 99%). According to GP4, 4i
0.364 mmol). The product 5l was obtained as a yellow oil (1.25 g,
1
7.19 mmol, 99%). H NMR (400 MHz, CDCl ): d=1.19 (s, 9H), 3.52
3
(
1.00 g, 6.67 mmol) and CO were converted to the corresponding
(dd, J=10.3 Hz, 3.6 Hz, 1H), 3.61 (dd, J=10.3 Hz, 4.5 Hz, 1H), 4.38
(dd, J=8.3 Hz, 5.8 Hz, 1H), 4.47 (dd, J=8.3 Hz, 8.3 Hz, 1H), 4.74–
2
carbonate 5i in the presence of 3j (121 mg, 0.339 mmol). The
product 5i was obtained as a colorless solid (1.28 g, 6.60 mmol,
9
1
13
1
4.80 ppm (m, 1H, CH); C{ H} NMR (100 MHz, CDCl ): d=27.24 (3ꢂ
3
1
9%). H NMR (300 MHz, CDCl ): d=4.16 (dd, J=10.6 Hz, 3.7 Hz,
CH ), 61.24 (CH ), 66.52 (CH ), 73.84 (C), 75.12 (CH), 155.12 ppm (C=
3
3
2
2
+
+
H), 4.26 (J=10.6 Hz, 4.3 Hz, 1H), 4.55 (J=8.5 Hz, 6.0 Hz, 1H), 4.63
O); MS (EI, 70 eV): m/z (%): 159 (16) [M ÀCH ], 59 (19) [C H O ], 57
3
3
7
+
(J=8.4 Hz, 8.3 Hz, 1H), 5.00–5.08 (m, 1H), 6.90–6.95 (m, 2H), 7.00–
(100) [C H ]; elemental analysis calcd (%) for C H O : C 55.16, H
4 9 8 14 4
13
1
7
.06 (m, 1H), 7.29–7.36 ppm (m, 2H); C{ H} NMR (100 MHz,
8.10; found: C 55.22, H 8.20.
CDCl ): d=66.19 (CH ), 66.85 (CH ), 74.08 (CH), 114.58 (2ꢂCH),
3
2
2
1
7
7
21.96 (CH), 129.66 (2ꢂCH), 154.63 (C=O), 157.72 ppm (C); MS (EI,
[
11a]
+
+
+
(2-Oxo-1,3-dioxolan-4-yl)methyl methacrylate (5m)
0 eV): m/z (%): 194 (71) [M ], 107 (100) [C H O ], 94 (74) [C H O ],
7
7
6
6
+
5
+
9 (30), 77 (93) [C H ], 66 (18), 65 (24) [C H ], 51 (23); elemental
6
5
5
According to GP4, glycidyl methacrylate (4m, 1.02 g, 7.18 mmol)
and CO were converted to the corresponding carbonate 5m in
the presence of 3j (129 mg, 0.361 mmol). The product 5m was ob-
tained as a colorless oil (1.32 g, 7.14 mmol, >99%) According to
analysis calcd (%) for C H O (194.18): C 61.85, H 5.19; found: C
10
10
4
2
6
1.92, H 5.20.
GP4, 4m (1.02 g, 7.16 mmol) and CO were converted to the corre-
sponding carbonate 5m in the presence of 3j (129 mg,
2
[39]
4-(Isopropyloxymethyl)-1,3-dioxolan-2-one (5j)
0
.361 mmol). The product 5m was obtained as a colorless oil
According to GP3, 2,3-epoxypropyl isopropyl ether (4j, 2.01 g,
7.4 mmol) and CO were converted to the corresponding carbon-
ate 5j in the presence of 3j (130 mg, 0.364 mmol). The product 5j
1
(1.33 g, 7.14 mmol, >99%). H NMR (300 MHz, CDCl ): d=1.97 (dd,
3
1
2
J=1.5 Hz, 1.0 Hz, 1H), 4.32–4.38 (m, 2H), 4.45 (dd, J=12.6 Hz,
3
5
.2 Hz, 1H), 4.59 (dd, J=8.7 Hz, 8.5 Hz, 1H), 4.95–5.02 (m, 1H),
was obtained as a yellow oil (2.63 g, 16.4 mmol, 94%). According
13
1
.67–5.69 (m, 1H), 6.17–6.19 ppm (m, 1H); C{ H} NMR (75 MHz,
to GP4, 4j (1.00 g, 8.61 mmol) and CO were converted to the cor-
2
CDCl ): d=18.07 (CH ), 63.38 (CH ), 66.03 (CH ), 73.78 (CH), 127.20
3
3
2
2
responding carbonate 5j in the presence of 3j (153 mg,
(CH ), 135.08 (C), 154.43 (C=O), 166.56 ppm (C=O); MS (EI, 70 eV):
2
0
.428 mmol). The product 5j was obtained as a yellow oil (1.30 g,
+
+
1
m/z (%): 186 (16) [M ], 69 (100) [C H O ], 68 (36); elemental analy-
4 5
sis calcd (%) for C H O (186.16): C 51.61, H 5.41; found: C 51.76, H
5.54.
8
.10 mmol, 94%). H NMR (400 MHz, CDCl ): d=1.17 (d, J=6.1 Hz,
3
8
10
5
6
H,), 3.59–3.69 (m, 3H), 4.38 (dd, J=8.4 Hz, 6.1 Hz, 1H), 4.49 (dd,
13
1
J=9.0 Hz, 8.2 Hz, 1H), 4.76–4.81ppm (m, 1H);
C{ H} NMR
(
(
(
(
100 MHz, CDCl ): d=21.75 (CH ), 21.85 (CH ), 66.40 (CH ), 67.08
3 3 3 2
CH ), 72.93 (CH), 75.11 (CH), 155.02 ppm (C=O); MS (EI, 70 eV): m/z
2
(
3aR,7aS)-3a,4,7,7a-tetrahydrobenzo-[1,3]-dioxol-2-one
+
+
+
%): 145 (9) [M ÀCH ], 130 (13) [C H O ], 88 (65) [C H O ], 73
3
5
6
4
3
4
3
[26b]
+
+
(5o)
100) [C H O ], 59 (36), 58 (27), 57 (80) [C H O ], 55 (15); elemental
4
9
3
5
analysis calcd (%) for C H O (160.17): C 52.49, H 7.55; found: C
7
14
4
In the presence of 3j (72 mg, 0.20 mmol), 7-oxabicyclo[4.1.0]hept-
[42]
5
2.58, H 7.47.
3
-ene (4o, 979 mg, 10.2 mmol) and CO were stirred for 16 h at
2
1
208C and 4.0 MPa. The crude product was filtered with CH Cl
2
2
over silica gel, and the volatiles were removed in vacuo. The prod-
[
40]
4
-(Isobutoxymethyl)-1,3-dioxolan-2-one (5k)
uct 5o was recrystallized from diethyl ether to give the desired
1
product as colorless needles (677 mg, 4.83 mmol, 47%). H NMR
According to GP3, 2-(isobutoxymethyl)oxirane (4k, 2.00 g,
5.3 mmol) and CO were converted to the corresponding carbon-
ate 5j in the presence of 3j (110 mg, 0.308 mmol). The product 5k
was obtained as a yellow oil (2.41 g, 13.8 mmol, 90%). According
to GP4, 4k (1.00 g, 7.70 mmol) and CO were converted to the cor-
responding carbonate 5k in the presence of 3j (135 mg,
.378 mmol). The product 5k was obtained as a yellow oil (1.21 g,
.96 mmol, 90%). H NMR (400 MHz, CDCl ): d=0.90 (d, J=6.7 Hz,
H), 1.87 (sept, J=6.6 Hz, 1H), 3.28 (d, J=6.7 Hz, 2H), 3.60 (dd, J=
1.0 Hz, 3.7 Hz, 1H), 3.68 (dd, J=11.0 Hz, 3.9 Hz, 1H), 4.41 (dd, J=
.3 Hz, 6.1 Hz, 1H), 4.50 (dd, J=8.3 Hz, 8.3 Hz, 1H), 4.81 ppm (m,
H); C{ H} NMR (100 MHz, CDCl ): d=19.09 (2ꢂCH ), 28.36 (CH),
6.28 (CH ), 69.79 (CH ), 75.07 (CH), 78.81 (CH ), 154.96 ppm (C=O);
(
5
300 MHz, CDCl ): d=2.19–2.28 (m, 2H), 2.55–2.65 (m, 2H), 4.97–
.03 (m, 2H), 5.90–5.98 ppm (m, 2H); C{ H} NMR (75 MHz, CDCl ):
3
3
1
2
13
1
d=26.95 (2ꢂCH ), 74.60 (2ꢂCH), 125.59 (2ꢂCH), 154.94 ppm (C=
2
+
+
O); MS (EI, 70 eV): m/z (%): 141 (3) [MÀH ], 140 (3) [M ], 95 (43),
2
+
+
7
+
8
1 (27) [C H ], 77 (14), 67 (100) [C H ], 54 (26) [C H ]; crystal
6
9
5
4
6
data for C H O , M=140.13, orthorhombic, space group Pnma, a=
7
8
3
0
6
6
3
1
1
2.5014(14), b=9.9830(11), c=5.1959(6) ꢃ, V=648.46(13) ꢃ , T=
50(2) K, Z=4, 2629 reflections measured, 825 independent reflec-
1
3
tions (Rint =0.0177), final R values (I>2s(I)): R =0.0361, wR =
1
2
1
0
.0930, final R values (all data): R =0.0419, wR =0.0979, GOF on
1 2
8
1
6
2
[29]
F : 1.081, 49 parameters.
1
3
1
3
3
2
2
2
+
MS (EI, 70 eV): m/z (%): 88 (9), 87 (14) [M ÀC H O ], 58 (13), 57
3
3
3
Acknowledgements
+
(
100) [C H ]; elemental analysis calcd (%) for C H O (174.19): C
4
9
8
14
4
5
5.16, H 8.10; found: C 55.30, H 7.86.
We wish to thank the Federal Ministry of Research and Education
BMBF) for financial support (Chemische Prozesse und stoffliche
(
[
41]
Nutzung von CO : Technologien fꢀr Nachhaltigkeit und Klima-
2
4
-(tert-Butoxymethyl)-1,3-dioxolan-2-one (5l)
schutz, grant 01 RC 1004A) as well as Prof. Matthias Beller for his
support and advice.
According to GP3, 2-(tert-butoxymethyl)oxirane (4l, 2.00 g,
5.4 mmol) and CO were converted to the corresponding carbon-
1
2
ate 5l in the presence of 3j (110 mg, 0.308 mmol). The product 5l
was obtained as a yellow oil (2.44 g, 14.0 mmol, 91%). According
Keywords: C1 building blocks · carbon dioxide fixation ·
halides · insertion · organocatalysis
to GP4, 4l (948 mg, 7.28 mmol) and CO were converted to the
2
corresponding carbonate 5l in the presence of 3j (130 mg,
ꢁ
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemCatChem 0000, 00, 1 – 10
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8
&
ÞÞ
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[
Received: October 13, 2014
2
Published online on && &&, 0000
ꢁ
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemCatChem 0000, 00, 1 – 10
&
9
&
ÞÞ
These are not the final page numbers!

FULL PAPERS
H. Bꢀttner, K. Lau, A. Spannenberg,
T. Werner*
&& – &&
Bifunctional One-Component Catalysts
for the Addition of Carbon Dioxide to
Epoxides
Couple up: Recyclable bifunctional
ammonium salts are identified as one-
component catalysts for the 100%
atom-economic coupling reaction of
bond accelerates the catalytic reaction
remarkably. This metal and solvent-free
process can be performed on a multi-
gram scale and is applied to the
synthesis of a naturally occurring cyclic
carbonate.
CO and epoxides even at 458C. The al-
2
cohol moiety that donates a hydrogen
ꢁ
2014 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
ChemCatChem 0000, 00, 1 – 10
&10
&
ÞÞ
These are not the final page numbers!