Selective Synthesis of Carbonates from Glycerol, CO 2, and Alkyl Halides Using tert -Butyltetramethylguanidine

Article abstract of DOI:10.1055/s-0037-1610027

Herein, we describe the guanidine-promoted synthesis of carbonates from glycerol, CO ₂, and alkyl halides. Specifically, a linear tricarbonate (1,2,3-tri- O -butoxycarbonylglycerol), a dicarbonate [butyl (2-oxo-1,3-dioxolan-4-yl)methyl carbonate] containing a linear and a cyclic moiety, and a cyclic monocarbonate (4-hydroxymethyl-2-oxo-1,3-dioxolan) were selectively obtained in good yields, which were strongly affected by the steric bulkiness of the guanidine group substituents. The developed method exhibits the advantages of high efficiency and mild conditions, thus being a powerful tool for the synthesis of value-added products from industrial by-products.

Full text of DOI:10.1055/s-0037-1610027

SYNLETT
0
9
3
6
-
5
2
1
4
1
4
3
7
-
2
0
9
6
©
Georg Thieme Verlag Stuttgart · New York
2018, 29, A–F
letter
A
en
Synlett
M. Mihara et al.
Letter
Selective Synthesis of Carbonates from Glycerol, CO , and Alkyl
2
Halides Using tert-Butyltetramethylguanidine
Masatoshi Mihara*a
Nt-Bu
Kaname Morogab
Tetsuo Iwasawab
Takeo Nakaia
Takatoshi Itoa
Toshinobu Ohnoa
Takumi Mizunoa
Me2N
NMe2
(2–6 equiv)
1
OCO2R1
OCO2R1
HO
OH
R O2CO
NMP
21–92%
10 examples
1
+
CO2
+ R X
0.7 MPa
OH
(2–10 equiv)
r.t. or 0 °C, 18 h
O
O
industrial by-products
O
Q = CO2Bu or H
0.1 MPa
86%
74%
50 °C, 4 h
selective synthesis by
OQ
the change of conditions
a
R1 = alkyl
Osaka Research Institute of Industrial Science and Technology,
value-added
products
1
-6-50 Morinomiya, Joto-ku, Osaka 536-8553, Japan
b
Faculty of Science and Technology, Ryukoku University, Otsu,
Shiga 520-2194, Japan
mihara@omtri.or.jp
Received: 16.03.2018
Accepted after revision: 30.04.2018
Published online: 12.07.2018
yl)methyl carbonate] containing a linear and a cyclic moiety6
are also known, being used as refrigeration oils, biomateri-
als for tissue engineering, adjuvants for agrochemicals,
electrolyte solvents for Li-ion batteries and display devices,
and coating films. In particular, these tri- and dicarbonates
have high potential as starting materials for degradable ali-
phatic polycarbonates. Although several catalytic syntheses
of the above cyclic monocarbonate from glycerol and CO2
DOI: 10.1055/s-0037-1610027; Art ID: st-2018-u0169-l
Abstract Herein, we describe the guanidine-promoted synthesis of
carbonates from glycerol, CO , and alkyl halides. Specifically, a linear tri-
carbonate (1,2,3-tri-O-butoxycarbonylglycerol), a dicarbonate [butyl
2
(
2-oxo-1,3-dioxolan-4-yl)methyl carbonate] containing a linear and a
cyclic moiety, and a cyclic monocarbonate (4-hydroxymethyl-2-oxo-
,3-dioxolan) were selectively obtained in good yields, which were
1
strongly affected by the steric bulkiness of the guanidine group substit-
uents. The developed method exhibits the advantages of high efficien-
cy and mild conditions, thus being a powerful tool for the synthesis of
value-added products from industrial by-products.
Table 1 Base-Promoted Synthesis of Carbonates from Glycerol, CO ,
and n-Butyl Bromide
2
a
base
DMSO
HO
OH
Key words carbon dioxide, glycerol, carbonates, guanidines
+
CO2 + BuBr
OH
The progressing global climate change requires the de-
O
O
velopment of efficient CO -utilization methods to decrease
BuO2CO
OCO2Bu
2
+
O
O
+
O
O
the atmospheric concentration of this greenhouse gas,
which can be used as a carbon source. It is currently recog-
nized as an attractive and versatile reagent in organic syn-
thesis because of its low cost and environmental friendli-
OCO2Bu
1a
OCO2Bu
2a
OH
3
1
Baseb
ness. Moreover, the ever-increasing global production of
Entry
NMR ratio 1a/2a/3
glycerol as a side-product of the biodiesel industry also ne-
cessitates the search for suitable utilization methods, e.g.,
those employing glycerol as the starting material for high
1
2
3
4
DBU
A
1:76:23
50:41:9
62:36:2
50:46:4
22:77:1
0:12:88
2
B
value-added products or as a green solvent. Therefore, the
C
simultaneous conversion of both CO and glycerol to valu-
2
able products is doubly advantageous from environmental
and economic perspectives, since two wastes are utilized at
the same time.
5
D
6 c
E
a
Reaction conditions: glycerol (1 mmol) was treated with n-BuBr (3.3 mmol)
Organic carbonates obtained from glycerol or/and CO2
are an important class of biomass-based valuable prod-
ucts. Besides the widely used cyclic monocarbonate of
in dimethyl sulfoxide (DMSO; 3 mL) under an atmosphere of CO (0.7 MPa)
in the presence of a base (3.3 mmol) at 25 °C for 18 h. 1a, 2a, and 3 were
2
given mainly from glycerol.
3
b
A: N-tert-butyl-N′,N′-dimethylacetamidine, B: 2-tert-butyl-1,1,3,3-te-
tramethylguanidine, C: 2-cyclohexyl-1,1,3,3-tetramethylguanidine, D: 7-
methyl-1,5,7-triazabicyclo[4.4.0]dec-5-ene, and E: 2-phenyl-1,1,3,3-te-
tramethylguanidine.
glycerol (4-hydroxymethyl-2-oxo-1,3-dioxolan or glycerol
4
carbonate), linear tricarbonates (1,2,3-tri-O-alkoxycarbon-
5
c
ylglycerol) and dicarbonates [alkyl (2-oxo-1,3-dioxolan-4-
Recovery of glycerol: about 39% NMR yield.
©
Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–F

B
Synlett
M. Mihara et al.
Letter
have already been reported, the corresponding yields did
not exceed 35% even under harsh conditions in the pres-
ence of dehydration agents.7 In addition, some reports
claim that glycerol carbonate can be efficiently prepared
significantly affected by the basicity and nucleophilicity of
9a
the organic base. Nevertheless, only DBU and 2-cyclohex-
9c
yl-1,1,3,3-tetramethylguanidine have been identified as
useful strong organic bases for the above synthesis. Al-
though a convenient synthesis of ethylene carbonates from
from glycerol and CO by noncatalytic methods, e.g., by us-
2
ing 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)–dibromo-
methane–ionic liquid or silver complex–propargylic alcohol
systems. However, to the best of our knowledge, the direct
CO and 1,2-diols using alkyl halides in the presence of DBU
2
has been reported,9 the DBU-assisted procedure has not
been successfully applied to the synthesis of linear dicar-
bonates of 1,2-diols except for the case of trans-cyclohex-
anediol, which does not readily undergo cyclization be-
cause of the inherent steric repulsion. On the other hand,
h
8
synthesis of the above tricarbonates and dicarbonates from
glycerol and CO has not been reported. In particular, the
2
environmentally benign synthesis of linear tricarbonates
presents a significant challenge. For example, transesterifi-
cation of dialkyl carbonates with glycerol in the presence of
potassium carbonate, a typical ecofriendly method of car-
bonates synthesis, was reported to exclusively afford the
thermodynamically most stable five-membered cyclic car-
we have already tackled the utilization of CO and glycerol,
2
succeeding in the synthesis of glycerol carbonate from glyc-
erol using sulfur10 and selenium as well as employing the
11
12
DBU-catalyzed reaction of CO2 with aminobenzonitrile.
Herein, we report a selective base-promoted synthesis of
3a
bonates. Therefore, tricarbonates are commonly prepared
by using reactive haloformate esters derived from hazard-
linear tricarbonates from glycerol, CO , and alkyl halides
2
under mild conditions.
5
a,c
ous phosgene,
which inspired us to develop a facile
The synthesis of linear tributylcarbonate 1a from glyc-
method of selectively preparing linear tricarbonates from
erol, CO , and n-butyl bromide in the presence of several
2
two industrial by-products, CO and glycerol.
strong organic bases was investigated as a model reaction
(Table 1). The use of DBU afforded dicarbonate 2a contain-
ing a linear and a cyclic moiety as the major product, along
with traces of 1a (entry 1). As DBU is known to be alkylated
by n-butyl bromide during the preparation of dialkyl car-
bonates,9a the reaction was carried out with a more bulky
and less nucleophilic acetamidine (base A), which resulted
in the formation of 1a in preference to 2a (entry 2). Further-
more, the use of tert-butyltetramethylguanidine (base B,
2
A number of methods for dialkyl carbonate synthesis
using CO instead of phosgene as the carbon source have
2
been developed. Among them, carboxylation of alcohols
with CO utilizing alkyl halides has been achieved in the
2
presence of inorganic or strong organic bases under mild
9
conditions. Since the base-promoted reaction proceeds
through the alkylation of the carbonate salt intermediate
formed from CO , alcohol, and the base, the product yield is
2
Table 2 Guanidine-Promoted Synthesis of 1a: Screening of Reaction Conditionsa
Nt-Bu
(base B)
HO
OH
2
Me N
NMe2
+
CO2 + BuBr
1a
+
2a 3
+
OH
Entry
Base (mmol)
CO
2
(MPa)
Temp (°C)
Solvent
Amount of solvent (mL) n-BuBr (mmol)
NMR ratio 1a/2a/3
1
2
3
4
5
6
7
8
9
3.3
3.3
3.3
3.3
3.3
3.3
3.3
3.3
3.3
3.3
6
0.7
0.1
1.7
0.7
0.7
0.7
0.7
0.7
0.7
0.7
0.7
0.7
25
25
25
50
0
DMSO
DMSO
DMSO
DMSO
NMP
3
3
3
3
3
3
3
3
–
1
1
1
3.3
3.3
3.3
3.3
3.3
3.3
3.3
3.8
3.3
3.3
6
62:36:2
33:60:7
57:40:3
49:47:4
40:51:9
70:28:2
2:66:32
7:76:17
33:58:9
81:18:1
90:10:0
25
25
25
25
25
25
25
NMP
MeCN
THF
none
NMP
10
11
12
NMP
b
6
NMP
10
93 :7:0
a
Reaction conditions: glycerol (1 mmol), reaction time (18 h). 1a, 2a, and 3 were given mainly from glycerol.
Isolated yield: 89%.
b
©
Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–F

C
Synlett
M. Mihara et al.
Letter
expected to be stronger than base A) increased the yield of
a, with the 1a/2a molar ratio decreasing with decreasing
solvents than acetonitrile and tetrahydrofuran (entries 1
and 6–8), even though carbonates were obtained even un-
der solvent-free conditions (entry 9). Moreover, decreasing
the solvent volume from 3 to 1 mL increased the 1a/2a ratio
(entries 6 and 10), with a similar effect achieved by using
an excess of n-butyl bromide and base (entries 10–12).
Consequently, the optimized mild conditions allowed 1a to
1
steric bulkiness of the guanidine substituents (entries 3–5).
Moreover, the above ratio was also strongly affected by the
basicity of the substituted guanidines (entry 6). Consider-
ing the scope of the alkylating reagent, n-butyl chloride was
inferior to n-butyl bromide, affording compound 3 and un-
reacted glycerol instead of compounds 1a and 2a under the
tested conditions.
be efficiently prepared from glycerol and CO in the pres-
2
ence of an alkylated guanidine.
With the base B in hand, we proceeded to optimize oth-
er reaction conditions (Table 2), showing that the use of
Subsequently, the optimized conditions were used to
investigate the scope of alkyl halides (Table 3).13 n-Butyl
bromide, sec-butyl halides, dodecyl bromide, allyl bromide,
and benzyl bromide smoothly reacted with glycerol in an
pressurized CO could effectively increase the yield of 1a,
2
whereas a further increase in pressure from 0.7 to 1.7 MPa
had no beneficial effect (entries 1–3). Similarly, tempera-
tures higher or lower than 25 °C also resulted in lower mo-
lar ratios of 1a (entries 1, 4, and 5), which were also consid-
erably influenced by the choice of solvent. Thus, N-meth-
ylpyrrolidinone and dimethyl sulfoxide were more suitable
atmosphere of pressurized CO to furnish the correspond-
2
ing trialkylcarbonates 1a–e in good to high yields (entries
1–6). Notably, better results were obtained for sec-butyl io-
dide than for the corresponding bromide because of the de-
creased yield of dicarbonate 2b observed in the former case
(
entries 2 and 3). Reactions with allyl and benzyl bromides
Table 3 Guanidine-Promoted Synthesis of Tricarbonates 1: Scope of
Alkyl Halides
were performed at low temperature to suppress the pro-
duction of 2d and 2e, affording the desired tricarbonates in
high yields (entries 5 and 6). In particular, the reaction was
applicable to alkyl bromides bearing ester, cyano, and ace-
tal groups, thus allowing the direct synthesis of functional-
ized tricarbonates 1f–h (entries 7–9) that are difficult to
prepare from the corresponding haloformate esters. More-
over, although terminal alkyne groups were not tolerated,
compound 1j, featuring an internal alkyne moiety, was ob-
tained in moderate yield along with 2j (entries 10 and 11).
However, no desired tricarbonates were obtained in the
cases of tert-butyl iodide and ethyl 3-bromopropionate be-
cause of the competing elimination of hydrogen halides
from these species (entries 12 and 13). Moreover, a poor
yield was also observed for 2-bromoethyl methyl ether ow-
ing to the competing formation of 2k (entry 14). Thus, sev-
eral tricarbonates were directly synthesized from glycerol,
a
base B
NMP
HO
OH
+
CO2
+
RX
OH
O
RO2CO
OCO2R
+
O
O
OCO2R
1
OCO2R
2
Entry
RX
1
Yield (%)
1
n-BuBr
s-BuBr
s-BuI
1a
89
61
82
81
92
90
81
81
79
2
1b
1b
1c
1d
1e
1f
3
4
n-C12
CH =CHCH
PhCH Br
EtOC(O)(CH
H
25Br
5b
6b
7
2
2
Br
CO , and alkyl halides by using tert-butyltetramethylguani-
dine as a promoter.
2
2
2
)
3
Br
The above reaction was further applied to the synthesis
of cyclic carbonates from glycerol, CO , and n-butyl bro-
8
NC(CH
2
)
4
Br
1g
1h
2
mide. Thus, the synthesis of 2a was investigated under the
conditions optimized for the preparation of 1a (Table 4),
with the slow addition of n-butyl bromide in an atmo-
9
O
O
(
CH2)4Br
sphere of CO (0.1 MPa) at 25 °C over 18 hours leading to
0b
0c
2
1
1
1
1
HC≡CCH
2
Br
(1i)
the relatively selective production of 2a (entry 1). Further-
more, an even higher selectivity was observed when the re-
action mixture was heated at 50 °C for four hours (entry
1b
2
MeC≡CCH
t-BuI
Br
1j
45d
0
2
14
3
EtOC(O)(CH
2
)
2
Br
0
2). Subsequently, the synthesis of 3 was attempted. A de-
crease in the amount of n-butyl bromide and guanidine to
four equivalents caused a decrease in the 2a/3 ratio (entry
3), with a further decrease to two equivalents resulting in
the highly selective formation of 3 (entry 4). Thus, cyclic
carbonates could be selectively obtained only by changing
the reaction conditions.
1
4
MeO(CH Br
2
)
2
1k
21e
a
2
Reaction conditions: glycerol (1 mmol), CO (0.7 MPa), alkyl halide (10
mmol), NMP (1 mL), base B (6 mmol), 25 °C, 18 h.
b
0
°C.
c
Compound 2i: 49%. Recovery of glycerol: 0%.
Compound 2j: 47%.
Compound 2k: 76%.
d
e
©
Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–F

D
Synlett
M. Mihara et al.
Letter
Table 4 Guanidine-Promoted Synthesis of 2a and 3: Screening of Re-
action Conditions
dride (conditions B, Table 5). As shown in Table 5, the guan-
idine-promoted reaction (conditions A) followed by acetyl-
ation (conditions B) afforded some carbonates. Entries 1–3
reveal the formation of linear monocarbonates 5a1 and 5a2,
which were then converted into the corresponding linear
dicarbonates 6a1 and 6a2 and the tricarbonate 1a.
a
base B
NMP
HO
OH
+
CO2 + BuBr
1a
+
2a 3
+
OH
Thus, the studied reaction was concluded to proceed
through the formation of carbonate salt 8 from glycerol,
Entry
Base
n-BuBr
(mmol)
Temp
(°C)
Time (h) total, NMR ratio
b
(
mmol)
drop/stir
1a/2a/3
CO , and guanidine, with its subsequent transformations af-
2
1
2
3
6
6
4
2
6
6
4
2
25
50
50
50
18, 6/12
4, 3/1
33:67:0
fording linear monocarbonates 5' that were further con-
verted to 6' and finally to 1 (Scheme 1). According to the
proposed mechanism, 5' cyclizes to 3, which is further car-
boxylated to afford 2. In a similar manner, the cyclization of
6' gives 2. In this cyclization, even if six-membered cyclic
carbonates were formed, it is considered that the six-mem-
bered carbonates were isomerized to five-membered ones
to give 2 and 3 excusively.15 In addition, the 5a1 and 6a1 ra-
tios exceeded the 5a2 and 6a2 ones (entries 1–3, Table 5),
indicating that the 1- and 3-hydroxyl groups of glycerol
were carboxylated more smoothly than the 2-hydroxyl one.
Moreover, the formation of cyclic carbonates 2a and 7 was
favored by increasing the temperature (entries 2 and 4) and
the amount of base (entries 4–6). However, the amount of
base did not affect the yield of cyclic carbonates at 25 °C
(entries 2 and 7). Accordingly, the combination of reaction
temperature and amount of base had a considerable effect
on the cyclization step. As described above, linear tricar-
bonates could be selectively produced (entry 12, Table 2) in
an atmosphere of pressurized CO2 by using excessive
c
0:95 :5
4, 3/1
0:80:20
0:8:92d
4
4, 3/1
a
Reaction conditions: glycerol (1 mmol), CO
2
(0.1 MPa), NMP (1 mL).
Total time: the sum of “drop” and “stir” times. Drop: time required for the
dropwise addition of n-BuBr into an NMP solution of glycerol and base B in
an atmosphere of CO . Stir: time of stirring the reaction mixtures after the
b
2
dropwise addition of n-BuBr.
c
Isolated yield: 86%.
d
Isolated yield: 74%.
The reaction of glycerol with CO (0.7 MPa) and n-BuBr
2
(
2.2 equiv) in the presence of base B (2.2 equiv) was
quenched after three hours to observe the reaction inter-
mediates (conditions A, entry 2, Table 5). Notably, the gas-
chromatographic (GC) analysis of the resulting mixtures
showed the production of only cyclic carbonates 2a and 3
along with 1a, which was ascribed to the conversion of lin-
ear carbonates to cyclic ones during the GC measurements.
Therefore, the unreacted hydroxyl groups in the resulting
mixtures were protected by treatment with acetic anhy-
Table 5 GC Analysis of Intermediates Observed in the Guanidine-Promoted Syntheses of Carbonatesa
Ac2O
Et3N
DMAP
base B
NMP
HO
OH
+
CO2
+
BuBr
conditions A
conditions B
OH
AcO
OAc
OCO2Bu
BuO2CO
OAc
OCO2Bu
O
AcO
OAc
OAc
5a1
6a1
OCO2Bu
OCO2Bu
BuO2CO
OCO2Bu
OCO2Bu
+
+
+
+
O
O
AcO
OCO2Bu
AcO
4
1a
OR
7
OAc
R = Ac
5a2
6a2
CO2Bu 2a
Entry
Base (mmol)
Temp (°C)
Time (h)
GC ratio 4/5a1/5a2/6a1/6a2/1a/7/2a
1
2
3
4
5
6
2.2
2.2
2.2
2.2
3.3
4.4
3.3
25
25
25
50
50
50
25
0.3
3
20:37:8:15:14:4:1:1
12:37:5:22:15:7:1:1
3:18:2:33:18:23:0:3
8:21:4:22:15:14:6:10
4:4:1:8:5:31:8:39
18
3
3
3
3
1:1:0:1:2:39:8:48
7
8:25:8:25:21:12:0:1
a
2 2 3
Reaction conditions: A: glycerol (1 mmol), CO (0.7 MPa), n-BuBr (2.2 mmol), NMP (1 mL); B: Ac O (3 mmol), Et N (3 mmol), DMAP (0.05 mmol), r.t., 2 h.
©
Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–F

E
Synlett
M. Mihara et al.
Letter
amounts of base to promote the formation of carbonate
salts, with other parameters corresponding to room tem-
perature, medium concentration, and excess alkyl halides
to suppress intramolecular cyclization.
In conclusion, the described reaction was proven to be
useful for the direct synthesis of linear and cyclic carbon-
ates from widely available inexpensive building blocks,
glycerol and CO , with this study being the first-time report
2
Alcohols produced in the cyclization step reacted with
of such direct synthesis. The developed method is particu-
larly useful because it allows the efficient synthesis of val-
ue-added products from two industrial by-products at am-
CO and alkyl halides in the presence of guanidine, afford-
2
ing dialkyl carbonates as by-products, e.g., dibutyl carbon-
ate (entry 2, Table 4; equation 1, Scheme 2). In addition,
when carboxylation of 2a was carried out by addition of n-
butyl alcohol under the conditions of entry 12 (Table 2) to
investigate the possibility of converting 2 into 1, compound
bient temperature and CO pressure, additionally featuring
2
the advantages of high selectivity, high yields, broad appli-
cability, and mild conditions.
1
a was obtained in only about 5% yield (equation 2, Scheme
Funding Information
2), which showed that 2a was only marginally converted
into 1a even under these conditions containing alcohols.
This work was supported by JSPS KAKENHI Grant Number 25410197
and the Daicel Award in Synthetic Organic Chemistry, Japan.
a
Jp
a
n
S
o
ecity
o
f
r
hte
P
or
m
o
itn
of
Secince
2(
5
4
1
0
1
9
7)
CO2
guanidine
OCO2–)
OH
(
HO
OH
HO
guanidineH+
Supporting Information
(
OH)
OH
OCO2–
Supporting information for this article is available online at
8
https://doi.org/10.1055/s-0037-1610027.
S
u
p
p
o
nrtogI
i
f
rm oaitn
S
u
p
p
ortioIgnfmr oaitn
– guanidineH X–
+
RX
References and Notes
(
OCO2R)
(OCO2R)
OH
CO2, RX
guanidine
CO2, RX
guanidine
HO
OH
RO2CO
1
(1) Selected reviews on CO as a carbon source in organic synthesis:
2
(
OH)
(OH)
+
+ –
–
guanidineH X–
OCO2R
– guanidineH X
OCO2R
(a) Sakakura, T.; Choi, J.-C.; Yasuda, H. Chem. Rev. 2007, 107,
2365. (b) Darensbourg, D. J. Chem. Rev. 2007, 107, 2388.
5'
6'
(c) Aresta, M.; Dibenedetto, A.; Angelini, A. Chem. Rev. 2014,
–
ROH
– ROH
114, 1709. (d) Liu, Q.; Wu, L.; Jackstell, R.; Beller, M. Nature.
Commun. 2015, 6, 5933. (e) Otto, A.; Grube, T.; Schiebahn, S.;
Stolten, D. Energy Environ. Sci. 2015, 8, 3283.
CO2, RX
guanidine
3
2
+
guanidineH X–
(2) Selected reviews on glycerol as a starting material: (a) Behr, A.;
Eilting, J.; Irawadi, K.; Leschinski, J.; Lindner, F. Green Chem.
2008, 10, 13. (b) Zhou, C.-H.; Beltramini, J. N.; Fan, Y.-X.; Lu, G. Q.
Chem. Soc. Rev. 2008, 37, 527. (c) Gu, Y.; Jérôme, F. Green Chem.
–
Scheme 1 Plausible mechanism of carbonate formation
2010, 12, 1127. (d) García, J. I.; García-Marín, H.; Pires, E. Green
CO2, RX
guanidine
Chem. 2014, 16, 1007. (e) Sutter, M.; Silva, E. D.; Duguet, N.;
Raoul, Y.; Métay, E.; Lemaire, M. Chem. Rev. 2015, 115, 8609.
3) Selected reviews and examples on organic carbonates obtained
from glycerol or/and CO2: (a) Rokicki, G.; Rakoczy, P.;
Parzuchowski, P.; Sobiecki, M. Green Chem. 2005, 7, 529.
ROH
ROCO2R (1)
+
–
guanidineH X–
(
base B
NMP
2
a + CO2
+
BuBr + BuOH
1a
(2)
(
b) Schäffner, B.; Schäffner, F.; Verevkin, S. P.; Börner, A. Chem.
Scheme 2 Reaction conditions: 2a (1 mmol), CO (0.7 MPa), n-BuBr (10
mmol), n-BuOH (3 mmol), base B (6 mmol), NMP (1 mL), 25 °C, 18 h
2
Rev. 2010, 110, 4554. (c) Ma, J.; Song, J.; Liu, H.; Liu, J.; Zhang, Z.;
Jiang, T.; Fan, H.; Han, B. Green Chem. 2012, 14, 1743.
(4) (a) Ochoa-Gómez, J. R.; Gómez-Jiménez-Aberasturi, O.;
Ramírez-López, C.; Belsué, M. Org. Process Res. Dev. 2012, 16,
The large influence of the choice of base on the yield of
389. (b) Sonnati, M. O.; Amigoni, S.; Taffin de Givenchy, E. P.;
1
(Table 1) was ascribed to the effective formation of car-
bonate salts in the presence of strong bases. Moreover, the
bulkiness of the guanidinium cation increased the nucleop-
hilicity of the carbonate anion, promoting the carboxyl-
ation of the remaining 2-hydroxyl group in 6' and also hin-
dering the electrophilic attack of alkyl halides on the guani-
dine moiety. Thus, base B enabled the efficient formation of
more nucleophilic glycerol carbonate salts even at room
temperature, suppressing cyclization and facilitating the
formation of linear tricarbonates.
Darmanin, T.; Choulet, O.; Guittard, F. Green Chem. 2013, 15,
283.
(5) (a) Togashi, H.; Sawada, H. JP 06087792A, 1994. (b) Dankers, P.
Y. W.; Zhang, Z.; Wisse, E.; Grijpma, D. W.; Sijbesma, R. P.;
Feijen, J.; Meijer, E. W. Macromolecules 2006, 39, 8763. (c) Bell,
G. A.; Ramsay, J. L.; Nouvel, N. I. US. Pat. Appl 20150250163A1,
2
015.
6) (a) Satsuma, M.; Kishi, Y.; Uetani, Y.; Nishiguchi, K.
JP 2008288128A, 2008. (b) Ikesu, S.; Kokeguchi, N.
(
JP 2009086582A, 2009. (c) Tale, N. V.; Jagtap, R. N.; Tathe, D. S.
Des. Monomers Polym. 2014, 17, 147.
©
Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–F

F
Synlett
M. Mihara et al.
Letter
(
7) (a) Aresta, M.; Dibenedetto, A.; Nocito, F.; Pastore, C. J. Mol.
EtOAc was added to the resulting mixture to precipitate the dis-
solved salt, the salt was removed with a Buchner funnel and
washed with EtOAc. The combined filtrate was concentrated in
Catal. A: Chem. 2006, 257, 149. (b) George, J.; Patel, Y.; Pillai, S.
M.; Munshi, P. J. Mol. Catal. A: Chem. 2009, 304, 1. (c) Ozorio, L.
P.; Pianzolli, R.; Machado da Cruz, L.; Miranda, J. L.; Turci, C. C.;
Guerra, A. C. O.; Souza-Aguiar, E. F.; Mota, C. J. A. Appl. Catal. A:
Gen. 2015, 504, 187. (d) Li, H.; Jiao, X.; Li, L.; Zhao, N.; Xiao, F.;
Wei, W.; Sun, Y.; Zhang, B. Catal. Sci. Technol. 2015, 5, 989.
1
vacuo, and the obtained product ratios were determined by H
NMR spectroscopic measurements. The crude product was
purified by silica gel column chromatography, affording linear
tricarbonates 1.
(
(
e) Zhang, J.; He, D. J. Chem. Technol. Biotechnol. 2015, 90, 1077.
f) Liu, J.; Li, Y.; Zhang, J.; He, D. Appl. Catal. A: Gen. 2016, 513, 9.
8) (a) Lim, Y. N.; Lee, C.; Jang, H.-Y. Eur. J. Org. Chem. 2014, 1823.
b) Zhou, Z.-H.; Song, Q.-W.; He, L.-N. ACS Omega 2017, 2, 337.
1,2,3-Tri-O-(2-butynyloxy)carbonylglycerol (1j)
IR (neat): 2959, 2924, 2323, 2241, 1756, 1442, 1384, 1237,
–1 1
(
(
1156, 961, 923, 789 cm . H NMR (600 MHz, CDCl ): δ = 1.87 (t,
3
(
J = 2.4 Hz, 9 H), 4.32 (dd, J = 12.0, 6.0 Hz, 2 H), 4.44 (dd, J = 12.0,
9) (a) Hori, Y.; Nagano, Y.; Fukuhara, T.; Teramoto, S.; Taniguchi, H.
Nippon Kagaku Kaishi 1987, 1408. (b) Oi, S.; Kuroda, Y.;
Matsuno, S.; Inoue, Y. Nippon Kagaku Kaishi 1993, 985.
4.8 Hz, 2 H), 4.70–4.73 (m, 6 H), 5.12–5.15 (m, 1 H) ppm. 13
C
NMR (151 MHz, CDCl ): δ = 3.59, 56.61, 56.72, 65.26, 72.12,
3
72.20, 72.71, 84.45, 84.54, 153.74, 154.16 ppm. HRMS (ESI): m/z
+
(
c) McGhee, W.; Riley, D. J. Org. Chem. 1995, 60, 6205. (d) Kim,
S.-I.; Chu, F.; Dueno, E. E.; Jung, K. W. J. Org. Chem. 1999, 64,
578. (e) Salvatore, R. N.; Flanders, V. L.; Ha, D.; Jung, K. W. Org.
Lett. 2000, 2, 2797. (f) Shi, M.; Shen, Y.-M. Molecules 2002, 7,
calcd for C18H20NaO [M + Na] : 403.1005; found: 403.1004.
9
(14) General Procedure for the Synthesis of Cyclic Carbonates (2a
and 3) Using Base B
4
Glycerol (1 mmol), base B (2 or 6 mmol), and NMP (1 mL) were
added to a glass vessel connected to an injection port equipped
3
86. (g) Yamazaki, Y.; Kakuma, K.; Du, Y.; Saito, S. Tetrahedron
2010, 66, 9675. (h) Kitamura, T.; Inoue, Y.; Maeda, T.; Oyamada,
with a three-way cock. The vessel was charged with CO from a
2
J. Synth. Commun. 2016, 46, 39.
10) Mizuno, T.; Nakai, T.; Mihara, M. Heteroatom Chem. 2010, 21, 99.
11) Mizuno, T.; Nakai, T.; Mihara, M. Heteroatom Chem. 2010, 21,
balloon, and it was stirred at 25 °C for 1 h. An alkyl bromide (2
or 6 mmol) was added dropwise at 50 °C for 3 h under 0.1 MPa
(
(
of CO pressure and further stirred for another 1 h. The workup
2
5
41.
12) Mizuno, T.; Mihara, M.; Nakai, T.; Iwai, T.; Ito, T. Synthesis 2007,
524.
13) General Procedure for the Synthesis of Linear Tricarbonates
Using Base B
and purification were the same as those reported in the general
procedure for the synthesis of compound 1.
(
(
2
2-Butynyl (2-oxo-1,3-dioxolan-4-yl)methyl carbonate (2j)
IR (neat): 2960, 2925, 2322, 2241, 1798, 1758, 1394, 1267,
–1
1
1
1170, 1088, 1053, 951, 789, 772 cm . H NMR (600 MHz,
A stainless steel autoclave was charged with glycerol (1 mmol),
base B (6 mmol), and NMP (1 mL), flushed three times with CO2,
and finally charged with CO2 to 0.7 MPa at room temperature.
The obtained mixture was magnetically stirred at 25 °C for 1 h,
and an alkyl halide (10 mmol) was added at room temperature
after CO2 evacuation, followed by repeated CO2 flush-
ing/charging to 0.7 MPa. The reaction mixture was magnetically
CDCl ): δ = 1.87 (t, 1.8 Hz, 3 H), 4.33 (dd, J = 12.6, 4.2 Hz, 1 H),
3
4.36 (dd, J = 9.0, 6.6 Hz, 1 H), 4.45 (dd, J = 12.6, 4.2 Hz, 1 H), 4.57
(t, J = 9.0 Hz, 1 H), 4.73 (q, J = 1.8 Hz, 2 H), 4.92–4.96 (m, 1 H)
13
ppm. C NMR (151 MHz, CDCl ): δ = 3.63, 56.98, 65.71, 66.09,
3
71.96, 73.24, 84.83, 154.05, 154.13 ppm. HRMS (ESI): m/z calcd
+
for C H NaO [M + Na] : 237.0375; found: 237.0368.
9
10
6
(15) Tryznowski, M.; Żotek-Tryzowska, Z.; Świderska, A.;
Parzuchowski, P. G. Green Chem. 2016, 18, 802.
stirred at 25 °C for 18 h under 0.7 MPa pressure of CO . After
2
©
Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–F