Tetrabutylammonium Salts: Cheap Catalysts for the Facile and Selective Synthesis of α-Alkylidene Cyclic Carbonates from Carbon Dioxide and Alkynols

Article abstract of DOI:10.1002/cctc.201701567

n-Tetrabutylammonium organic salts were used for the first time as catalysts for the coupling of CO₂ with 2-methyl-3-butyn-2-ol to form an α-methylene cyclic carbonate. Final yields up to 98 % were reached in less than 10 h at 353 K and 3 MPa under solvent-free conditions. A particular synergistic effect between the cation and the anion of the organocatalyst was demonstrated through catalyst screening. Online kinetic studies by Attenuated Total Reflectance (ATR) IR spectroscopy correlated to DFT calculations revealed compelling evolution of solvation of the catalyst during the reaction that provided insight into the underlying reason for the observed unique kinetics and selectivity. Such in-depth fundamental mechanistic and kinetic studies enabled determination and comprehension of the key parameters favoring the design of novel, highly active and selective catalysts for valorization of CO₂ as a chemical feedstock.

Full text of DOI:10.1002/cctc.201701567

Accepted Article
Title: Tetrabutyl ammonium salts: cheap catalysts for the facile and
selective synthesis of a-alkylidene cyclic carbonates from CO2
and alkynol
Authors: raphael mereau, bruno Grignard, amelie boyaval, Christophe
Detrembleur, christine Jerome, and Thierry TASSAING
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To be cited as: ChemCatChem 10.1002/cctc.201701567
Link to VoR: http://dx.doi.org/10.1002/cctc.201701567
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Tetrabutyl ammonium salts: cheap catalysts for the facile and
selective synthesis of -alkylidene cyclic carbonates from CO2
and alkynol
Raphaël Méreau[a], Bruno Grignard[b], Amélie Boyaval[a,b], Christophe Detrembleur[b], Christine Jerome[b],
Thierry Tassaing[a]*
Dedication ((optional))
CO2 into α-alkylidene cyclic carbonates at low temperature and
pressure. Beside metal complexes that generally require a strict
Abstract: n-tetrabutyl ammonium organic salts are used for the first
time as catalysts for the coupling of CO2 with 2-methyl-3-butyn-2-ol
to form α-methylene cyclic carbonate. The final yields could reach
98% in less than 10 hours at 353K and 3MPa under solvent free
conditions. A particular synergistic effect between the cation and the
anion of the organocatalyst is demonstrated through catalyst
screening. Online kinetic studies by ATR-IR spectroscopy correlated
to DFT calculations reveal a compelling evolution of the solvation of
the catalyst during the reaction that provide an understanding of the
underlying reason for the observed unique kinetics and selectivity.
Such in-depth fundamental mechanistic and kinetic studies enable
determining and comprehending the key parameters favouring the
design of novel highly active and selective catalysts for the
valorisation of CO2 as a chemical feedstock.
avoidance of moisture/air, organocatalysts such as tertiary
[15]
phosphine [14], bicyclic amidines, guanidines
(used as a solvent)
and ionic liquids
[16]
have been used to promote the coupling
of CO2 with propargylic alcohols. In order to improve the
selectivity and the efficiency, more sophisticated organocatalysts
such as N-heterocyclic carbene (NHC)[17]
,
N-heterocyclic
olefin[18]
,
and alkoxide-functionalized imidazolium betaine[19]
have also been developed for the selective preparation of α-
alkylidene cyclic carbonates. However, the low stability and/or
moisture sensitivity of these catalysts might hamper their use for
industrial applications. In this context, efforts are still needed to
identify stable, cheaper and less/non-toxic organic catalysts that
promote the selective carboxylative coupling of CO2 with
propargylic alcohols.
Carbon dioxide is a cheap, renewable and easily accessible
source of carbon for producing high-value fine chemicals and
monomers.[1] In the last years, many academic and industrial
researches have been devoted to the development of novel and
sustainable synthetic pathways to convert CO2 into cyclic
In this communication, we report the first use of n-tetrabutyl
ammonium (TBA) salts for the efficient and selective synthesis
of α-alkylidene cyclic carbonates from CO2 and a propargylic
alcohol under solvent free conditions (Scheme 1). Through
catalyst screening, kinetic studies and DFT calculations, we
demonstrate a synergistic effect between the cation and the
anion of the organocatalyst and hydrogen bonding solvation
effects on the anion that are responsible for the efficiency of the
system and an unexpected kinetic behaviour.
carbonates finding wide applications as intermediates in the
[2]
preparation of pharmaceuticals and agrochemicals products
.
Thus, five and six-membered cyclic carbonates are obtained
from the catalytic coupling of CO2 with different substrates such
[5]
[6]
as epoxides [3], oxetanes [4], propargylic alcohols
and diols
using appropriate organic or transition metal catalysts. In
particular, α-alkylidene cyclic carbonates, that are intermediates
of great interest in organic[7] and polymer[8] synthesis, are
synthesized by coupling CO2 with propargylic alcohols. Until now,
much work has focused on the use of metallic catalysts as
a)
b)
[5a]
[5b]
recently reviewed by Song et al.
and Kleij et al.
In
particular, silver based catalyst systems such as
[11]
AgOAc/(DBU),[9] Ag2WO4/Ph3P,[10] [(PPh3)2Ag]2CO3,
AgOAc/
[P66614][DEIm][12] and more recently ZnBr2/Et3N based catalytic
systems[13] have proven to be efficient for the transformation of
[a]
[b]
PhD, A. Boyaval, Dr. R. Méreau, Dr. T. Tassaing, Institut des
Sciences Moléculaires (ISM), UMR5255 CNRS, Université de
Bordeaux, 351 Cours de la libération, F-33405 Talence Cedex,
France.
Scheme 1. a) CO2/2-methyl-3-butyn-2-ol coupling; b) Structures of the
organocatalysts investigated for the chemical fixation of CO2 into α-methylene
carbonate.
E-mail: thierry.tassaing@ u-bordeaux.fr
-
-
-
-
The influence of the counter-anion (I-, Br-, Cl-, Br3 , I3 , PF6 , N3 ,
NCO-, CN-, SCN-, MDA- (Malondialdehyde), OAc-) of n-tetrabutyl
ammonium (TBA+) was investigated for the reaction between
CO2 and 2-methyl-3-butyn-2-ol under solvent-free conditions
(Table 1, entries 2-13). At 3 MPa and 353 K, only traces of
product were observed without catalyst as highlighted by a
conversion of only 3% after 70h (Table 1, entry 1). Halide anions
Dr. B. Grignard, Pr. C. Jérôme, Pr. C. Detrembleur, Center for
Education and Research on Macromolecules (CERM), Chemistry
Department, B6a, University of Liège, allée du 6 août, 4000 Liege,
Belgium
Supporting information for this article is given via a link at the end of
the document.((Please delete this text if not appropriate))
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10.1002/cctc.201701567
ChemCatChem
COMMUNICATION
-
either under their X- or X3 form were found to be ineffective
based salts may result from a synergism between the anion and
the cation of these ammonium salts. Indeed, we expect that with
a bulkier cation, the electrostatic interaction between the cation
and the anion should be weaker and the anion may display a
higher Lewis basicity. Nevertheless, the high bulkiness of
(TOAOAc) brings steric hindrance, thereby impeding on coupling
reaction. Thus, it appears that (TBAOAc) displays an optimum
alkyl chain length as it displays the highest catalytic activity in
comparison with the shorter (TMAOAc) and longer (TOAOAc)
ammonium salts. Finally, although other conventional
organocatalysts such as TBD and MTBD displays a good
efficiency, the selectivity towards the formation of 1 respectively
falls to 15% and 50% (entry 17-18).[15b]
under the given conditions (Table 1, entries 2 - 6). The same
conclusion is drawn for PF6- (entry 7).
Table 1. Coupling reaction of CO2 with 2-methyl-3-butyn-2-ol catalyzed by
various organic and inorganic salts. Reaction conditions: alcohol = 500 µl,
catalyst loading = 5 mol%, T=353K, P=3 MPa.
To go further in the comprehension of the reaction mechanism,
detailed kinetic investigations were performed by in situ
Attenuated Total Reflectance (ATR)-Infrared (IR) spectroscopy
by using the most active and selective catalysts (see Figure S1).
These studies enable us to determine the kinetic profiles, the
reaction yields, and the selectivity of the reaction that are
affected by various parameters (anion type, pressure,
Entry
Catalyst
Time (h)
Conversion
(%)
Selectivity
1:2
nd[a]
1
2
/
70
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
6
3
0
TBAI
-
3
TBABr
0
-
4
TBACl
<3
0
nd[a]
5
TBABr3
TBAI3
-
temperature, catalyst loading). Figure
1 shows the time
6
0
-
dependence of the yield of the synthesis of 1 and 2 catalyzed by
various tetrabutyl ammonium salts (5 mol%) at 80°C and 3MPa.
7
TBAPF6
TBAN3
TBANCO
TBACN
TBASCN
TBAMDA
TBAOAc
NH4OAc
TMAOAc
TOAOAc
TBD
0
-
8
51
93
97
<3
25
60
0
99:1
95:5
87:13
nd[a]
99:1
99:1
-
9
10
11
12
13
14
15
16
17
18
30
4
92:8
99:1
15:85
50:50
87
91
MTBD
[a] nd: not determined
-
Interestingly, TBA+ with N3 as counter-anion displays
a
significant efficiency with a conversion of 51% after 6h of
reaction and a high selectivity (99%) towards the formation of
the cyclic carbonate 1 (entry 8) with negligible side product 2
formation that results from the addition of 2-methyl-3-butyn-2-ol
to 1. Other nitrogen-containing anions such as NCO- and CN-,
are found to drastically boost the catalyst activity with a
conversion of 93% and 97%, respectively, but at the expense of
the selectivity towards the formation of 1 (entry 9-10) that
respectively falls to 95% and 87%. SCN- is however found to be
ineffective (entry 11). A high selectivity of 99% is obtained with
TBA+ with MDA- or OAc- counter-anion with a conversion of 25%
or 60% (entry 12-13). As TBAOAc displays the best compromise
between catalytic activity and selectivity, we have then screened
a series of acetate based salts with different cations. Inorganic
cations based acetate salts, namely CuOAc, NaOAc and KOAc,
were found totally ineffective for the coupling reaction. Although
NH4OAc has no catalytic activity (entry 14), tetramethyl acetate
(TMAOAc) and tetraoctyl acetate (TOAOAc) display some
catalytic activity with a conversion of 30% and 4%, respectively,
and a selectivity towards the formation of 1 of 92% and 99%,
respectively (entry 15-16). Therefore, the efficiency of acetate
Figure 1. Influence of the counter-anion of tetrabutyl ammonium on the
formation of the α-methylene cyclic carbonate 1 (ν = 1824 cm-1) and acyclic
carbonate side product 2 with time. Conditions: 2-methyl-3-butyn-2-ol (500µL),
catalyst = TBA-Anion= 5 mol%, T = 353K, p CO2 = 3MPa
As previously observed, the selectivity in 1 is excellent. A final
yield of 1 of about 98% is obtained after about 10h for TBAOAc
and TBAN3 and after about 15h for TBAMDA. On the other hand,
although TBACN and TBANCO display a faster kinetics, they
are less selective as the final yield in 1 is about 85 and 90%
respectively, in line with the screening results. Thus, it appears
that slower kinetics is beneficial to the conversion and to the
selectivity of the reaction. Regarding the kinetic profiles of the
cyclic carbonate formation, they display a peculiar shape that
does not fit a pseudo-first order kinetics as we would expect for
such reaction when CO2 is used in excess. Regarding the
representative case of TBAOAc, the kinetic profile can be
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10.1002/cctc.201701567
ChemCatChem
COMMUNICATION
M062X functional using 6-311G(d,p) basis sets (see Supporting
Information). The calculated wavenumbers for the ν3 stretching
vibration of the different complexes are reported in Fig. S2. The
experimental spectrum observed at about 2028 cm-1 during the
first 5.5 hours of reaction is well interpreted for a 1:4 complex.
Then, the broad profile centered at 2012 cm-1 observed at an
intermediate time of 5.5-7 hours is associated to smaller
roughly divided in two parts: an almost linear evolution of the
yields in 1 up to about 50-60% and then a speeding up of the
reaction until the maximum yield is reached. Such observed
unusual kinetic behaviour is roughly the same for all the other
ammonium salts.
To shed light on this unusual phenomenon, the reaction
catalyzed by TBAN3 was further studied by in-depth in-situ ATR-
IR kinetic measurements by following the intense band
associated with the asymmetric vibration ν3 of the azide anion in
the spectral range 1950-2050 cm-1 (see Figure 2).
complexes, mainly 1:2 complex associated to
a
weak
contribution of both 1:3 and 1:1 complexes. Finally, during the
final part of the reaction, the band at 2000 cm-1 can be assigned
to free azide anions as reported previously by Darensbourg et
al.[20] Rationalization of experimental ATR-IR spectra data (Fig.
2) with theoretical ones (Fig. S2) suggests that the initial
hydrogen bonding solvation shell stabilizing the charged azide
anion limit its catalytic activity probably through a decrease of its
pKa value.[21] Thus, when 1 is formed during the first seven
hours of the reaction, the hydrogen bonding solvation shell
around the azide anion is progressively weakened as evidenced
by the progressive shift of the azide anion peak from 2028 cm-1
(1:4 complex) to 2012 cm-1 (1:2 complex). Then, the peak at
2012 cm-1 finally vanishes at the expense of the peak of the free
-
azide anion N3 that is the unique component observed at the
end of the reaction. Thus, in the second part of the reaction, as
more and more azide free molecules (with an expected higher
pKa) are available to activate other 2-methyl-3-butyn-2-ol
molecules, the kinetic of the reaction is speeded up with time.
The observed unusual kinetic behaviour for this reaction is
clearly due to an evolution during the reaction of the hydrogen
bond solvation shell formed by 2-methyl-3-butyn-2-ol molecules
around the azide anions. The same observation has been done
on the the stretching vibration of the cyanate anion (NCO-) (see
Supporting Information).
As TBAOAc was identified as one of the most selective catalyst,
it was chosen as the model catalyst for further investigating the
influence of temperature, pressure and catalyst loading (see
supporting information). As a general rule, we observe that
increasing the temperature and the catalyst loading fasten the
reaction but has
a detrimental effect on the selectivity.
Figure 2. Evolution as a function of time of the ATR-IR spectra for 2-methyl-3-
butyn-2-ol (500 µL) catalyzed by TBAN3 (5 mol%) under 3 MPa of CO2 and at
353 K. Insert: zoom on the azide anion contribution at t=0 (purple line), t=7h
(red line) and t=14h (blue line)
Interestingly, increasing the pressure speeds up the reaction
and improves the selectivity. This can be explained by the
higher CO2 concentration dissolved in the alkynol phase at
higher pressure that favors the reaction.[22] Thus, in the
pressure range investigated 1-5 MPa, the optimal conditions to
maximize the yield of 1 under solvent free conditions are
obtained at T=353K, P=5 MPa and 5 mol% of TBAOAc.
On the spectrum corresponding to the initial solution at T=353 K
and P=3 MPa, we detect the band associated to the azide anion
at 2028 cm-1. During the first 5.5 hours of the reaction, the
position and intensity of this band do not evolve, whereas the
intensity of bands associated to α-methylene carbonate, namely,
the ν(C=O) stretching mode at 1827 cm-1 and the ν(C=C)
stretching mode at 1680 cm-1, increases in line with the
formation of 1. Importantly, after that period of time that
corresponds to about 40% conversion of 2-methyl-3-butyn-2-ol
into 1, the band associated to azide smoothly shifts towards
lower frequencies, from 2028 cm-1 after 5.5 h to 2012 cm-1 after
7 h of reaction (70% conversion). In order to understand the
origin of this shift of frequency during the reaction, Density
Functional Theory (DFT) calculations of geometries, energies,
To give a detailed insight into the reaction mechanism, we have
performed Density Functional Theory (DFT) calculations. The
Gibbs energy profiles obtained at the M06-2X/6-311G(d,p) level
for the uncatalysed and TBAOAc catalyzed (with one or two
alkynol) reactions are depicted on Figure 3. The optimized
structures of the corresponding intermediates and transition
states are reported in the Supporting Information. Initial state
(zero energy) corresponds to the sum of the Gibbs energy of
each compound. As reported previously
formation of a pre-reaction Van der Waals complex (VdW), the
uncatalysed reaction is composed of two elementary steps,
namely, the CO2 electrophilic attack on the hydroxyl (TS1=50.7
kcal.mol−1) and an intramolecular ring closure (TS2=68.6
18b], after the
[15b,
-
and vibrational frequencies of different N3 :2-methyl-3-butyn-2-ol
complexes (1:1, 1:2, 1:3 and 1:4) were then carried out with the
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10.1002/cctc.201701567
ChemCatChem
COMMUNICATION
kcal.mol−1). The overall reaction is exothermic by 14.2 kcal.mol-1
and the rate determining step is the second step of the reaction
that represents the highest energy transition state of the reaction
(68.6 kcal.mol−1) explaining the very low conversion obtained
without catalyst. The TBAOAc catalysed reaction has been
modelled following a two-elementary process where the acetate
anion activates the hydroxyl group of the alkynol. We have
calculated the Gibbs energy profiles considering one or two
alkynol molecules to explicitly account for solvation effects. We
do not have considered the alternative pathway in which a CO2
molecule can be activated by the nucleophilic acetate anion as it
has been previously found that this pathway was not
favourable.[16] The initial step (TS1 at 3.9 kcal.mol−1)
corresponds to the deprotonation of the hydroxyl by the acetate
anion with the simultaneous nucleophilic attack of the alkoxide
anion onto the
with the hydrogen bonding solvation effects and the kinetics
observed experimentally.
In this communication, n-tetrabutyl ammonium organic salts are
used as catalysts for the coupling of CO2 with 2-methyl-3-butyn-
2-ol to form α-methylene cyclic carbonate. In particular, TBAOAc
and TBAN3 enable the selective and quantitative synthesis of α-
alkylidene cyclic carbonates from CO2 and an alkynol with 98%
yields in less than 10 hours at 353K and 3 MPa under solvent
free conditions. The unique kinetic profiles and frequency shifts
of the anion peak evidenced by online ATR-IR spectroscopy and
elucidated by DFT calculations are related to a remarkable
evolution of the hydrogen bonding solvation of the catalyst
during the reaction. This work should help pushing away the
limitations of organocatalysts and clearly opens novel avenues
to the design of stable, cheap and metal free catalyst able to
promote the selective synthesis of α-alkylidene cyclic carbonates
under mild and solvent free conditions.
Experimental Section
-
The Supporting Information contains details on experimental and
computational methods.
Acknowledgements The authors of Liège thank the
“Region Wallonne” in the frame of the CO2Green, and Flycoat
projects, the "Belgian Science Policy" in the frame of the
"Interuniversity Attraction Poles Programme (IAP VII/5)
–
Functional Supramolecular Systems" and the "Fonds National
pour la Recherche Scientifique” (F.R.S.-FNRS) for financial
supports. The PhD fellowship of A. Boyaval was co-funded by
the “Conseil Regional d‘Aquitaine” and the “University of LIEGE”
through the international doctoral school program. We also
thank computational facilities provided by the MCIA (Mesocentre
de Calcul Intensif Aquitain) of the University of Bordeaux
financed by the ‘‘Conseil Regional d’Aquitaine’’. C.D. is
Research Director by F.R.S.-FNRS.
Figure 3. Free energy profile for α-methylene carbonate formation without
catalyst (yellow) and catalyzed by TBAOAc considering one alkynol (green) or
two alkynol molecules (blue). The Lewis structures of the intermediates and
transition states are displayed for the TBAOAc catalyzed reaction considering
one alkynol molecule
Keywords: ammonium salts • carbon dioxide • α-methylene
carbonate • organocatalysis
carbon atom of CO2 to form a [TBA]+[carbonate]− ionic pair
intermediate IR (-2.9 kcal.mol−1) with the release of acetic acid.
In the second step TS2 (19.8 kcal.mol−1), the intramolecular
nucleophilic addition from the carbonate anion to the C≡C bond
with the simultaneous pronation of the alkenyl anion by acetic
acid leads to the formation of 1 and the regeneration of TBAOAc.
The overall energy of the catalysed process is drastically
lowered in comparison to that calculated without catalyst thus
explaining the good experimental efficiency reported above for
this catalyst. The same mechanism holds when two alkynol
molecules are considered although the overall energy profile is
lower in energy than that reported considering only one alkynol.
This is due to the stabilization mechanism that involves
additional intermolecular hydrogen bonds by the second alkynol
molecule at each step of the process (see Supporting
Information) that particularly impacts the initial van der Waals
complex and the intermediate. As a result, the activation barriers
are higher with two alkynol molecules (ΔG= 13.5 and 26.7
kcal/mol) than with only one (ΔG= 6.6 and 22.5 kcal/mol) in line
[1] a) T. Sakakura, J. C. Choi, H. Yasuda, Chem. Rev. 2007, 107, 2365-
2387; b) C. Maeda, Y. Miyazaki, T. Ema, Catal. Sci. Tech. 2014, 4,
1482-1497; c) G. Fiorani, W. Guo, A. W. Kleij, Green Chem. 2015,
17, 1375-1389.
[2] a) A.-A. G. Shaikh, S. Sivaram, Chem. Rev. 1996, 96, 951-976; b) L.
Maisonneuve, O. Lamarzelle, E. Rix, E. Grau, H. Cramail, Chem.
Rev. 2015, 115, 12407-12439; c) B. Grignard, J. M. Thomassin, S.
Gennen, L. Poussard, L. Bonnaud, J. M. Raquez, P. Dubois, M. P.
Tran, C. B. Park, C. Jerome, C. Detrembleur, Green Chem. 2016, 18,
2206-2215.
[3] a) M. North, R. Pasquale, C. Young, Green Chem. 2010, 12, 1514-
1539; b) M. Cokoja, M. E. Wilhelm, M. H. Anthofer, W. A.
Herrmann, F. E. Kühn, ChemSuschem 2015, 8, 2436-2454; c) S.
Gennen, M. Alves, R. Méreau, T. Tassaing, B. Gilbert, C.
Detrembleur, C. Jerome, B. Grignard, ChemSuschem 2015, 8, 1845-
1849; d) M. Alves, B. Grignard, S. Gennen, R. Mereau, C.
Detrembleur, C. Jerome, T. Tassaing, Catal. Sci. Tech. 2015, 5,
This article is protected by copyright. All rights reserved.

10.1002/cctc.201701567
ChemCatChem
COMMUNICATION
4636-4643; e) M. Alves, B. Grignard, R. Mereau, C. Jerome, T.
Tassaing, C. Detrembleur, Catal. Sci. Tech. 2017, 7, 2651-2684.
[4] a) J. Rintjema, W. Guo, E. Martin, E. C. Escudero-Adan, A. W. Kleij,
Chemistry 2015, 21, 10754-10762; b) C. Martín, G. Fiorani, A. W.
Kleij, ACS Catal. 2015, 5, 1353-1370; c) M. Alves, B. Grignard, A.
Boyaval, R. Méreau, J. De Winter, P. Gerbaux, C. Detrembleur, T.
Tassaing, C. Jérôme, ChemSuschem 2017, 10, 1128-1138.
[5] a) Q.-W. Song, L.-N. He, in Advances in CO2 Capture,
Sequestration, and Conversion, Vol. 1194, American Chemical
Society, 2015, pp. 47-70; b) J. Rintjema, A. W. Kleij, Synthesis 2016,
DOI: 10.1055/s-0035-1562520.
[6] M. Tamura, M. Honda, Y. Nakagawa, K. Tomishige, J. Chem.
Technol. Biotechnol 2014, 89, 19-33.
[7] a) V. Besse, F. Camara, C. Voirin, R. Auvergne, S. Caillol, B.
Boutevin, Polym. Chem. 2013, 4, 4545-4561; b) Y. Zhao, Z. Yang, B.
Yu, H. Zhang, H. Xu, L. Hao, B. Han, Z. Liu, Chemical Science
2015, 6, 2297-2301.
[8] S. Gennen, B. Grignard, T. Tassaing, C. Jérôme, C. Detrembleur,
Angew. Chem. Int. Ed. 2017, 56, 10394-10398.
[9] W. Yamada, Y. Sugawara, H. M. Cheng, T. Ikeno, T. Yamada, Eur.
J. Org. Chem. 2007, 2007, 2604-2607.
[10] Q.-W. Song, B. Yu, X.-D. Li, R. Ma, Z.-F. Diao, R.-G. Li, W. Li, L.-
N. He, Green Chem. 2014, 16, 1633-1638.
[11] Q.-W. Song, W.-Q. Chen, R. Ma, A. Yu, Q.-Y. Li, Y. Chang, L.-N.
He, ChemSuschem 2015, 8, 821-827.
[12] K. Chen, G. Shi, R. Dao, K. Mei, X. Zhou, H. Li, C. Wang, Chem.
Comm. 2016, 52, 7830-7833.
[13] J. Hu, J. Ma, Q. Zhu, Q. Qian, H. Han, Q. Mei, B. Han, Green Chem.
2016, 18, 382-385.
[14] a) J. Fournier, C. Bruneau, P. H. Dixneuf, Tetrahedron Lett. 1989, 30,
3981-3982; b) Y. Kayaki, M. Yamamoto, T. Ikariya, J. Org. Chem.
2007, 72, 647-649.
[15] a) N. D. Ca, B. Gabriele, G. Ruffolo, L. Veltri, T. Zanetta, M. Costa,
Adv. Synth. Catal. 2011, 353, 133-146; b) A. Boyaval, R. Méreau, B.
Grignard, C. Detrembleur, C. Jerome, T. Tassaing, ChemSuschem
2017, 10, 1241-1248.
[16] J. Qiu, Y. Zhao, Z. Li, H. Wang, M. Fan, J. Wang, ChemSuschem
2017, 10, 1120-1127.
[17] Y. Kayaki, M. Yamamoto, T. Ikariya, Angew. Chem. Int. Ed. 2009,
48, 4194-4197.
[18] a) Y. B. Wang, Y. M. Wang, W. Z. Zhang, X. B. Lu, J. Am. Chem.
Soc. 2013, 135, 11996-12003; b) W. Li, N. Yang, Y. Lyu, J. Org.
Chem. 2016, 81, 5303-5313.
[19] Y.-B. Wang, D.-S. Sun, H. Zhou, W.-Z. Zhang, X.-B. Lu, Green
Chem. 2014, 16, 2266-2272.
[20] D. J. Darensbourg, A. I. Moncada, W. Choi, J. H. Reibenspies, J. Am.
Chem. Soc. 2008, 130, 6523–6533.
[21] A. Shokri, A. Abedin, A. Fattahi, S. R. Kass, J. Am. Chem. Soc. 2012,
134, 10646-10650.
[22] M. Zaky, A. Boyaval, B. Grignard, R. Méreau, C. Detrembleur, C.
Jérôme, T. Tassaing, J. Supercrit. Fluids 2017, 128, 308-313.
This article is protected by copyright. All rights reserved.

10.1002/cctc.201701567
ChemCatChem
COMMUNICATION
COMMUNICATION
Raphaël Méreau, Bruno Grignard,
Amélie
Boyaval,
Christophe
Detrembleur, Christine Jerome, Thierry
Tassaing*
Page No. – Page No.
Tetrabutyl ammonium salts: cheap
catalysts for the facile and selective
synthesis of -alkylidene cyclic
carbonates from CO2 and alkynol
n-tetrabutyl ammonium organic salts are used for the first time as catalysts for the
coupling of CO2 with 2-methyl-3-butyn-2-ol to form α-methylene cyclic carbonate.
The yields of the end product could reach 98% in less than 10 hours at 353K and 3
MPa under solvent free conditions. A synergistic effect between the cation and the
anion of the organocatalyst and solvation effects on the anion are demonstrated
through catalyst screening, kinetic studies and DFT calculations
This article is protected by copyright. All rights reserved.