Cooperative catalyst system for the synthesis of oleochemical cyclic carbonates from CO2 and renewables

Article abstract of DOI:10.1039/c6gc00671j

Phosphonium salts and various (transition-) metals were studied as catalysts in the synthesis of carbonated oleochemicals from the corresponding epoxides and carbon dioxide. In combination with tetra-n-butylphosphonium bromide molybdenum compounds were identified as highly active co-catalysts for the formation of cyclic carbonates. The co-catalyst accelerates the conversion of the epoxidized fatty acid ester considerably. The chemo- as well as the stereoselectivity of the carbonated oleochemicals can be controlled by the choice of the catalyst and the reaction conditions. Under optimized reaction conditions this new catalyst system allows the conversion of both mono- and polyepoxidized oleo compounds into the corresponding carbonates in good to excellent yields up to >99% under comparatively mild reaction conditions. This procedure has been applied to the synthesis of a potential renewable plasticizer and works well even at larger scale (200 g).

Full text of DOI:10.1039/c6gc00671j

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Cooperative catalyst system for the synthesis of
oleochemical cyclic carbonates from CO and
2
Cite this: DOI: 10.1039/c6gc00671j
renewables†
a
a
b
b
Nils Tenhumberg, Hendrik Büttner, Benjamin Schäffner, Daniela Kruse,
c
a
Michael Blumenstein and Thomas Werner*
Phosphonium salts and various (transition-) metals were studied as catalysts in the synthesis of carbo-
nated oleochemicals from the corresponding epoxides and carbon dioxide. In combination with tetra-
n-butylphosphonium bromide molybdenum compounds were identified as highly active co-catalysts for
the formation of cyclic carbonates. The co-catalyst accelerates the conversion of the epoxidized fatty
acid ester considerably. The chemo- as well as the stereoselectivity of the carbonated oleochemicals can
be controlled by the choice of the catalyst and the reaction conditions. Under optimized reaction con-
ditions this new catalyst system allows the conversion of both mono- and polyepoxidized oleo com-
pounds into the corresponding carbonates in good to excellent yields up to >99% under comparatively
mild reaction conditions. This procedure has been applied to the synthesis of a potential renewable plasti-
cizer and works well even at larger scale (200 g).
Received 7th March 2016,
Accepted 11th April 2016
DOI: 10.1039/c6gc00671j
www.rsc.org/greenchem
resources as well as the recycling and exploiting of carbon
dioxide into the value chain. These oleochemical carbonates
Introduction
The utilization of renewable resources as an alternative feed- can be used for several applications and are already employed
stock to petrochemicals has attracted much attention in recent as novel precursors for the synthesis of non-isocyanate poly-
1
–7
years. In this context, widespread and inexpensive vegetable urethanes (NIPU). Moreover, the reaction of cyclic carbonates
oils are used in various applications in the chemical indus- and amines permits not only the formation of polyurethanes
8
,9
try. For example, epoxidized plant oils and fatty acid deriva- but also the replacement of toxic isocyanates and additionally,
14–19
tives are employed as plasticizers and stabilizers in plastics interfering by-product formation can be prevented.
Oleo-
such as polyvinyl chloride, as starting material for epoxy chemical carbonates are also suggested as starting materials
resins, as reactive diluents for paints and as intermediates for for polyesters and polycarbonates, potential industrial lubri-
1
0,11
20,21
polyurethane-polyol production.
fatty acids and their methyl esters are discussed as sustainable ling reaction of epoxides with CO
and valuable intermediates for the synthesis of eco-friendly field of research and various homo- and heterogeneous cata-
Moreover, epoxidized cants, fuel additives and polymer plasticizers.
The coup-
2
is an intensively studied
1
2
22–30
lubricants as well as for carbonated oleochemicals produced lysts have been reported.
Commonly nucleophilic organic
by the coupling reaction of epoxides and carbon dioxide. The salts are employed as (co-)catalyst. Additionally, Lewis acids
utilization of CO has become a major field of research produ- are able to activate epoxides for the nucleophilic ring opening
2
cing value-added organic chemicals from this C1 building by coordination and as a result the formation of the cyclic car-
1
3
block. In this context the 100% atom efficient reaction bonate can be accelerated. Hence, there are numerous reports
between CO2 and fossil-based epoxides is an attractive reac- on acidic co-catalysts and recent progress has been made by
3
1,32
33–35
tion. The conversion of epoxidized vegetable oils and fatty acid employing complexes based on aluminum,
iron(III),
or
3
6–38
39–41
derivatives into cyclic carbonates benefits in two different zinc
as well as niob compounds.
However, only a few
ways; the synthesis of novel oleo compounds from renewable reports deal with special emphasis on the formation of
internal cyclic carbonates and the respective stereo-
2
3,42
selectivity.
This may be attributed to the fact that internal
a
Leibniz-Institut für Katalyse e. V. (LIKAT Rostock), Albert-Einstein-Str. 29 a, 18059
epoxides are less reactive than terminal epoxides because of
steric hindrance.
Carbonated oleo compounds are typically prepared from
4
3–46
Rostock, Germany. E-mail: thomas.werner@catalysis.de
b
Evonik Industries AG, Paul-Baumann-Str. 1, 45772 Marl, Germany
c
Hobum Oleochemicals, Seehafenstraße 20, 21079 Hamburg, Germany
the corresponding epoxidized oleo-derivatives and CO using
†
Electronic supplementary information (ESI) available. See DOI: 10.1039/
2
c6gc00671j
tetra-n-butylammonium bromide ([Bu N]Br) as catalyst. For
4
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instance, Tamami et al. reported the catalytic synthesis of car- lyst for the synthesis of oleochemical cyclic carbonates in
bonated soybean oil (CSBO) from epoxidized soybean oil combination with tetra-n-butylphosphonium bromide
ESBO) at atmospheric CO pressure. However, a reaction time ([Bu P]Br) as a source for a nucleophile. In 1980 Kisch et al.
of 70 h at 110 °C was needed to obtain full conversion employ- reported 0.5 mol% molybdenum(V) chloride in combination
(
2
4
1
9
ing [Bu N]Br as catalyst. With the intention to produce poly- with 3 mol% triphenyl phosphane as catalysts for the synthesis
4
5
2,53
urethanes from CSBO Yeganeh et al. employed 5.0 mol% of propylene carbonate at room temperature.
Bu N]Br in combination with 2.5 mol% calcium chloride to under these conditions an extraordinary long reaction time of
convert ESBO with CO for 72 h at 110 °C and ambient 7 days was required to obtain 78% yield. Furthermore, in 2011
However,
[
4
2
4
7
pressure. An improved protocol for the synthesis of carbo- Chen et al. reported the direct synthesis of cyclic carbonates
nated oleo compounds was described by Doll et al. using form the respective terminal olefin employing MoO (acac) as
However, both an epoxidation catalyst. However, in the cycloaddition reac-
reactions suffer from high catalyst loading of 5 mol% Bu NBr tion of the respective epoxide and CO the molybdenum cata-
and either long reaction time of 70 h or harsh reaction con- lyst was inactive. This report will give a full account on the
2
2
2
1,48
54
supercritical CO2 as a reaction medium.
4
2
1
9
2
1,48
dition of p(CO ) = 100 bar.
A composite catalyst compris- coupling reaction of CO2 and epoxides based on renewable
2
ing SnCl
activity compared to separately employed catalysts [Bu
4 2 4
·5H O and [Bu N]Br showed an increased catalytic oleochemicals utilizing tetra-n-butylphosphonium salts in
5
5
4
N]Br or combination with metal-based co-catalysts. Different organo-
SnCl , respectively. A very active system composed of [Bu N]Br catalysts were tested in order to study the influence of the
18
4
4
and a Cr(III)-substituted silicotungstate was employed by halide on the reaction. Furthermore, the influence of the
Leitner et al. to obtain improved results at 100 °C in supercriti- catalyst concentration and the reaction conditions were
4
9
cal carbon dioxide. However, in contrast to mono-epoxidized studied in detail with respect to the chemoselectivity of the
oleo compounds the polyoxometalate system seems to be less reaction as well as for the stereoselectivity of the produced
active for the conversion of poly-epoxidized oleo compounds cyclic carbonates. Under optimized reaction conditions a
as side reactions were encountered. Schäffner et al. tested variety of epoxidized fatty acid methyl esters were converted to
simple alkali halides in combination with phase transfer cata- the corresponding cyclic carbonates and the respective dia-
2
lysts in the reaction of epoxidized methyl linoleate with CO to stereoisomers were isolated. Additionally, epoxidized vege-
2
0
the respective bis-carbonate. Sodium iodide and 15-crown-5 tables oils were employed to evaluate the catalyst system for
as well as the combination of potassium iodide and 18-crown- the formation of carbonated oils which represent potential pre-
6
proved to be very active catalyst systems in the model reac- cursor molecules for non-isocyanate polyurethanes. Also a
tion at 100 °C, 100 bar and 17 h with a conversion of 94% and reaction scale up was realized to test the corresponding oleo-
0%, respectively. Rokicki et al. already reported in 2006 that chemical cyclic carbonates as feedstock for the production of
9
KI and 18-crown-6 can catalyze the carbonization of epoxidized bio-based plasticizers.
soybean oil under somewhat harsh reaction conditions of
5
0
1
30 °C and 6 MPa. However, Schäffner et al. tested several
poly-ethylene-glycols of different molecular weights as alterna-
tive and inexpensive phase transfer catalysts. In the presence
Results and discussion
2
of 3.5 wt% KI and 3.5 wt% PEG400 84% of the epoxidized The conversion of epoxidized methyl oleate 2a with CO to car-
methyl linoleate was selectively converted to the corresponding bonated methyl oleate (CMO) 3a was studied as model reaction
bis-carbonate. Based on these results a life cycle analysis (LCA) for the synthesis of carbonated oleo chemicals. Beforehand,
was performed to evaluate environmental impacts for the the model substrate epoxidized methyl oleate cis-2a was pre-
replacement of diisononyl phthalate (DINP) by carbonated pared by oxidation of methyl oleate (cis-1a) with hydrogen per-
5
6
fatty methyl esters (CFAME) as potential plasticizers. Major oxide.
savings of CFAME were accounted for greenhouse gas emis- subsequent coupling with CO
sions and primary energy demand. Recently, Jerome and Tas- products of this reaction is shown in Scheme 1.
saing et al. reported two-component catalyst system based on Although the diastereomeric pure epoxide cis-2a was
N]Br and Brønsted acids as co-catalyst. The conversion employed as starting material in the coupling reaction with
of epoxidized linseed oil and CO by [Bu N]Br was increased CO both diastereoisomers of CMO cis-3a and trans-3a were
An overall reaction sequence including the
2
and the expected products (by-)
5
7
5
1
[Bu
4
2
4
2
distinctly while phenolic or perfluoro Brønsted acids as co- formed as products (Table 1). Depending on the catalyst
catalysts were present. Detailed kinetic studies revealed opti- system and the reaction conditions the formation of trans-
mized reaction conditions of 120 °C, 5.0 MPa, 10 h, 2.2 mol% epoxidized methyl oleate trans-2a as well as 9-ketostearic acid
[
Bu N]Br and 2.2 mol% perfluoro tert-butanol to couple CO2 methyl ester 4a and 10-ketostearic acid methyl ester 4b were
4
and epoxidized linseed oil in an organocatalytic approach.
In a preceded screening of Lewis acids as co-catalyst and recent results regarding the utilization of CO
suitable nucleophilic catalysts the reaction of methyl oleate and the development of sustainable catalyst recycling
and CO was investigated to produce cyclic carbonates based methods, the catalyst screening was performed at 100 °C,
on oleochemicals. Herein, we report the utilization of molyb- p(CO , 100 °C) = 50 bar, 16 h and solvent-free conditions
observed as by-products in very small amounts. Based on our
2
as a C1 synthon
2
2
5
8–64
denum compounds and tungstic acid as highly active co-cata- (Table 1).
Carbonated oleo compounds are typical pre-
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almost exclusively the cis-isomer (cis-3a) and cis : trans ratio of
9
0 : 10 was observed. With increasing atomic number of the
halide, both chemo- and stereoselectivity decreased noticeably.
Accordingly, for [Bu P]Br still an excellent chemoselectivity of
4% was observed but [Bu P]I led only to 71% (entries 2 and
4
9
4
4
+
4
). Among the [Bu P] -based catalysts the bromide showed the
highest catalytic activity and the following order of reactivity
for [Bu P]X was observed X = Br > Cl > I. This order of reactivity
4
reflects a combination of nucleophilicity (Cl > Br > I) and
4
9
leaving group character (I > Br > Cl). Hence, the co-catalyst
screening was conducted using 2 mol% [Bu P]Br and an equi-
4
molar amount of the respective Lewis acid. With aluminum-
based co-catalysts (entries 5 and 6) and calcium chloride (entry
7) the yields of the cyclic carbonate 3a were considerably
increased up to 62%. A significant improvement was observed
while molybdenum compounds as well as tungstic acid
(
H WO ) as co-catalyst were present (entries 8–14). Molyb-
2 4
Scheme 1 General procedure of the synthesis of carbonated methyl
oleate 3a.
denum compounds and especially MoO
well as H WO are reported as catalysts for the hydroxylation
of fatty acid methyl esters by H O .
3 2 2
and MoO (acac) as
2
4
6
5–67
In these reactions the
2
2
pared from the corresponding epoxidized oleo compounds corresponding epoxide is formed as intermediate and both
and CO using [Bu N]Br which represents the benchmark cata- transition metals are probably able to activate the epoxide for
2
4
lyst. Under this reaction conditions a conversion of 39% of cis- the nucleophilic ring-opening by water. Therefore, we assumed
a and a yield of 32% of the cyclic carbonate 3a was observed that both compounds are suitable co-catalysts for the acti-
if tetra-n-butylammonium bromide was employed as catalyst vation of the epoxides 2 in the coupling reaction with CO to
2
2
(
entry 1). As an alternative to [Bu N]Br the respective phos- form cyclic carbonates 3. In fact, the highest yield of 84% of
4
phonium salt was tested in order to compare the impact of the CMO 3a was obtained using MoO3 as co-catalyst in combi-
cations (entry 2). In the presence of tetra-n-butylphosphonium nation with [Bu P]Br (entry 8). Compared to single organocata-
4
bromide 49% of the epoxide cis-2a was converted while an lyst [Bu P]Br, the yield of 3a was almost doubled from 46% to
4
excellent selectivity of 94% was determined (entry 2). Since 84%. However, the selectivity towards CMO 3a decreased to
selectivity and conversion of [Bu P]Br were increased distinc- 85% and the formation of ketone 4 increased slightly to 6%. In
4
tively compared to [Bu N]Br further investigations regarding general, we observed that an employment of a co-catalyst led
4
the effects of the halide compound were conducted with the to cis : trans-ratios of 3a between 69 : 31 and 40 : 60, which was
phosphorus-based catalysts. The employment of [Bu P]Cl led less selective than single organocatalyst [Bu P]Br alone (entries
4
4
to the formation of carbonate 3a solely and a high selectivity 2 and 5–14).
of 99% was determined (entry 3). With regard to the stereo-
Investigations concerning the concentration of the co-cata-
selectivity of carbonated methyl oleate 3a [Bu P]Cl provided lyst showed that even small amounts of MoO resulted in a sig-
4
3
a
Table 1 Screening of different catalysts and co-catalysts for the synthesis of cyclic carbonate 3
Conversion (%)
Selectivity (%)
Yield (%)
Entry
Catalyst
Co-catalyst
cis-2a
3a
cis : trans
3a
trans-2a
4
1
2
3
4
5
6
7
8
9
[Bu
[Bu
[Bu
[Bu
[Bu
[Bu
[Bu
[Bu
[Bu
[Bu
[Bu
[Bu
[Bu
[Bu
4
4
4
4
4
4
4
4
4
4
4
4
4
4
N]Br
P]Br
P]Cl
P]I
P]Br
P]Br
P]Br
P]Br
P]Br
P]Br
P]Br
P]Br
P]Br
P]Br
—
—
—
—
Al(OiPr)
AlCl
CaCl
39
49
39
35
66
87
71
99
80
83
96
93
94
80
82
94
99
71
76
71
86
85
90
89
85
83
77
93
46 : 56
71 : 29
90 : 10
57 : 43
56 : 44
54 : 46
51 : 49
66 : 34
66 : 34
69 : 31
49 : 51
40 : 60
52 : 48
66 : 34
32
46
38
25
50
62
61
84
72
74
82
77
72
74
1
0
0
0
1
1
1
0
0
0
2
2
4
0
1
0
0
1
5
5
2
6
1
1
3
3
5
1
3
3
2
MoO
MoO
3
2
10
11
12
13
14
Na
MoO
Mo(CO)
MoO (acac)
WO
2
MoO
4
·2H
2
O
H
2
4
6
2
2
H
2
4
a
2
Reaction conditions: 5.0 mmol cis-2a, 2.0 mol% catalyst, 2.0 mol% co-catalyst, p(CO , 100 °C) = 50 bar, 100 °C, 16 h, solvent-free.
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a
Table 2 Catalyst variation of binary catalytic system
both chemo- and stereoselectivity decreased and the formation
of ketone 4 was increased slightly (entries 4–6). In the presence
of 0.25 mol% MoO high chemoselectivity towards 3a with
3
cis : trans 3a trans-2a 4a 91% was obtained, while high conversion of cis-2a and good
yield on 3a was observed, too.
Conversion (%) Selectivity (%)
Yield (%)
MoO
Entry (mol%) cis-2a
3
3a
1
2
3
4
5
6
—
49
90
95
98
99
99
94
91
91
89
88
85
71 : 29
68 : 32
64 : 36
60 : 40
57 : 43
66 : 34
46
82
86
87
87
84
0
1
1
1
1
0
0
2
2
3
3
6
Therefore, a catalyst concentration of 2 mol% [Bu
.25 mol% of MoO as a co-catalyst was the optimum ratio.
Moreover, the results at high co-catalyst concentration imply
that MoO can promote the formation of by-products 4 (entry
). According to the reaction results and recent reports,
4
P]Br and
0.10
0.25
0.50
1.00
2.00
0
3
3
2
8,31,68
6
a
Reaction conditions: 5.0 mmol cis-2a, 2.0 mol% [Bu
4
P]Br,
a plausible reaction mechanism for the formation of carbo-
nated methyl oleate 3a, and the by-products trans-2a as well as
ketone 4 is depicted Scheme 2. The first step in the reaction
mechanism involves the activation of the epoxide cis-2a by the
0
.1–2.0 mol% MoO , p(CO , 100 °C) = 50 bar, 100 °C, 16 h, solvent-free.
3
2
nificant improvement in the conversion of cis-2a (Table 2).
High yields ≥82% and selectivities up to 91% of 3a were
already observed employing 0.1 mol% or 0.25 mol% of MoO
entries 2 and 3). Indeed, higher amounts of MoO3 of
.50–2.00 mol% resulted in excellent conversion of cis-2a, but
co-catalyst MoO
MoO an enhancement of the coupling efficiency compared to
Bu P]Br alone was observed. This cooperative effect is attribu-
3
([Mo]; (I)). In general, in the presence of
3
3
[
4
(
0
ted to the C–O bond polarization by coordination of MoO
3
to
cis-2a which accelerates the ring-opening of the internal
6
8
epoxide cis-2a by the halide. Subsequently, the nucleophilic
reaction of the bromide forms an alcoholate (II) which results
in an inversion of the configuration at the respective carbon
atom. Notably, no conversion is observed in the absence of the
phosphonium salt. This indicates the involvement of the
bromide in the epoxide opening resulting in the formation of
alcoholate (II) which seems to be the initial step in both reac-
tion pathways. Alcoholate (II) is able to attack CO and forms a
2
linear carbonate species (III). Due to the fact, that both dia-
stereoisomers cis- and trans-3a were produced, it is reasonable
to consider both types of nucleophilic substitutions, S
2 in the ring-closure of the linear carbonate species.
In aprotic solvents nucleophilic substitutions involving
chlorides react predominantly via S 2 mechanism due to the
N
1 and
S
N
N
weak leaving group character of the chloride while iodides
rather tends to react in a S 1 mechanism. Hence, further coup-
N
ling experiments were conducted employing [Bu
4
P]-based
organocatalysts with different halides and MoO
3
to confirm
the duality of ring-closure (Table 3).
Tetra-n-butylphosphonium chloride ([Bu
4
P]Cl) in combi-
nation with MoO led to the formation of carbonate 3a with
3
high chemo- and stereoselectivity (entry 1). Nearly complete
retention of the stereochemistry of the starting material cis-2a
Scheme 2 Proposed reaction mechanism for the synthesis of carbo- was observed and 3a was obtained with a cis : trans ratio of
nated methyl oleate 3a.
9
4 : 6. In the S 2 pathway of the proposed mechanism the
N
a
Table 3 Chemo- and stereocontrol of the coupling reaction of cis-2a and CO
2
producing 3a depending on the halide
Conversion (%)
Selectivity (%)
Yield (%)
Entry
Catalyst
cis-2a
3a
cis : trans
3a
trans-2a
4a
1
2
3
[Bu
[Bu
[Bu
4
P]Cl
4
P]Br
4
P]I
64(39)
95(49)
89(35)
92(99)
91(94)
79(71)
94 : 6(90 : 10)
64 : 36(71 : 29)
39 : 61(57 : 43)
59(38)
86(46)
70(25)
0(0)
1(9)
7(0)
0(0)
2(0)
11(1)
a
4
Reaction conditions: 5.0 mmol cis-2a, 2.0 mol% [Bu P]X, 0.25 mol% MoO
3
, p(CO
2
, 100 °C) = 50 bar, 100 °C, 16 h, solvent-free. Results in par-
3
enthesis were obtained in absence of MoO .
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aliphatic carbonate anion attacks the C
β
atom and an inversion Table 5 Variation of the reaction temperature and effects on the coup-
a
ling reaction of cis-2a and CO
2
of the configuration occurs (IIIa) (Scheme 2). Hence, the rela-
tive configuration of substrate cis-2a will be retained and cis-3a
will be produced. The employment of [Bu P]Br and especially
4
Conversion (%) Selectivity (%)
Yield (%)
of [Bu P]I resulted in the formation of higher amounts of Entry T (°C) cis-2a
3a cis : trans 3a trans-2a 4a
4
trans-3a with cis : trans ratios of 64 : 36 and 39 : 61, respectively
1
2
3
4
80
90
100
120
37
57
95
>99 82 : 18
>99 79 : 21
91 64 : 36
88 58 : 42
37
57
86
87
0
0
1
1
0
1
2
6
(entries 2 and 3). A loss of the stereochemical information of
cis-2a occurred. In contrast to the S 2 pathway, the formation
N
>99
of a carbenium ion (IV) after bromide dissociation of the
a
linear carbonate anion (IIIb) in the S
N
1 pathway enables the
4
Reaction conditions: 5.0 mmol cis-2a, 2.0 mol% [Bu P]Br, 0.25 mol%
3 2
MoO , p(CO , T) = 50 bar, 16 h, solvent-free.
formation of both cis-and trans-3a. Therefore, it can be
assumed that the formation of thermodynamically favored car-
bonate trans-3a proceeds via S
N
1 ring-closure. In addition,
when [Bu P]I and MoO were employed the formation of the
The reaction temperature was investigated in the range of
by-products trans-2a and 4 were increased too and yields up to 80–120 °C (Table 5). Within 80–100 °C both the conversion of
and 11% were obtained, respectively (entry 3). These by-pro- cis-2a and the yield of 3a increased considerably with ascend-
4
3
7
ducts are most reasonably formed via [Mo] dissociation and/or ing temperature (entries 1–3). At 120 °C full conversion of cis-
Meinwald rearrangement of intermediate (V). Considering 2a was obtained, but the selectivity towards 3 decreased notice-
these results, the chemo- and especially the stereoselectivity ably (entry 4). The formation of ketone 4 as a by-product was
exceedingly depend on the halide species of [Bu P]X catalysts. still low, however a certain yield of 6% was detected. Accord-
4
As a consequence, the stereoselectivity can be controlled by ingly, the selectivity of the carbonate 3a decreased to 88%.
the choice of the catalyst. A similar stereochemical control in Also the formation of the thermodynamically favored carbon-
the formation of fossil-based cyclic carbonates was observed ate trans-3a increased at elevated temperature of 120 °C.
by Kleij et al. employing tetra-n-butylammonium salts and a However, at 100 °C both an excellent reactivity of the catalyst
4
2
special dinuclear iron complex. In summary, among the system and a high chemoselectivity towards the formation
tested organocatalysts [Bu P]Br combines high activity and cyclic carbonate 3a were observed (entry 3). Hence, further
4
high chemoselectivity which result from both, good nucleophi- investigations of the coupling reactions of epoxide cis-2a and
licity and good leaving group ability. Thus, further investi- CO
gations regarding the catalyst concentration were conducted
2
were carried out at 100 °C.
The dependence of the CO
cyclic carbonate 3a is depicted in Fig. 1. Within the range from
P]Br nearly quantitative 10 to 50 bar CO high conversions ≥95% of the epoxide cis-2a
pressure for the synthesis of
2
using [Bu
4
P]Br (Table 4).
In the presence of 2.0 mol% of [Bu
4
2
conversion of epoxide cis-2a and a high yield of 86% of carbon- were obtained. The synthesis of carbonated oleochemicals
ate 3a was obtained (entry 5). A decrease of catalyst amount fol- often is performed at high pressure ≥100 bar under supercriti-
lowed the trends observed in the reaction screening regarding
the co-catalyst concentration (Table 2) and led to rather low con-
versions of cis-2a and cyclic carbonate 3a yield. However, if no
4
[Bu P]Br was present no formation of the cyclic carbonate 3a
was observed indicating that MoO acted only as co-catalyst and
3
was not able to catalyze the coupling reaction between the
epoxide cis-2a and CO
lyst concentration investigations, screening experiments regard-
ing temperature, CO pressure and reaction time were
conducted employing 2.0 mol% [Bu
2
on its own (entry 1). In addition to cata-
2
4 3
P]Br and 0.25 mol% MoO .
a
4
Table 4 Variation of the catalyst concentration of [Bu P]Br
Conversion (%) Selectivity (%) Yield (%)
[
Bu
4
P]Br
Entry (mol%)
cis-2a
3a
cis : trans 3a trans-2a 4a
1
2
3
4
5
—
1
11
31
74
95
0
—
0
9
28
65
86
0
0
2
1
1
0
1
2
4
2
0.25
0.50
1.00
2.00
83 61 : 39
90 79 : 21
88 71 : 29
91 64 : 36
Fig. 1 Effect of the CO
2
pressure in the coupling reaction of cis-2a and
a
Reaction conditions: 5 mmol cis-2a, 0–2.0 mol% [Bu
, p(CO , 100 °C) = 50 bar, 100 °C, 16 h, solvent-free.
4
P]Br, 0.25 mol% CO2. Reaction conditions: 5.0 mmol cis-2a, 2.0 mol% [Bu P]Br,
4
MoO
3
2
0
.25 mol% MoO
3
, p(CO
2
, 100 °C) = 5–50 bar, 100 °C, 16 h, solvent-free.
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cal reaction conditions to realize high conversion and selecti-
2
0,21,48,49
vity.
Br and MoO
In contrast, the catalytic system based on [Bu P]
was even able to convert 98% of cis-2a at 10 bar
4
3
with an excellent selectivity of 84%. In general, a distinct trend
regarding the chemo- and stereoselectivity was also observed
in dependence of the applied CO
2
pressure. At high pressure
≥
30 bar CO high selectivities ≥90% towards carbonate 3a
2
were obtained. In contrast to this at a rather low pressure of 5
bar carbonate 3a was formed only with a moderate selectivity
of 62%. Moreover, both by-products trans-2a and 4 were
formed in amounts yielding 10% and 11%, respectively. Thus,
a pressure of at least 10 bar is appropriate whereas the best
result regarding reactivity and selectivity was obtained at 50
bar. Accordingly, investigations to evaluate the optimized reac-
tion time were carried out and the respective results are
plotted in Fig. 2. In a series of batch experiments with a reac-
tion time of 4–24 h at 100 °C and p(CO , 100 °C) = 50 bar con-
2
versions, yields and selectivities were determined. Conversions
of ≥95% were obtained after 16 h. The highest yield of carbon-
ate 3a amounting to 94% was achieved after 20 h. Further
Scheme 3 Isolated yields of oleochemical carbonates 3 employing the
prolonging of reaction time did not lead to any improvement binary catalyst system [Bu
4
P]Br and MoO
3
. Conversion and selectivities
in brackets were determined by H NMR spectroscopy. Reaction con-
ditions: 2.0 mol% [Bu P]Br, 0.25 mol% MoO , p(CO , 100 °C) = 50 bar,
00 °C, 20 h. [b] 3.2 mol% [Bu P]Br, 0.4 mol% MoO . [c] 40 h. [d] 2.0 mol%
Bu P]Br/epoxide moiety and 0.25 mol% MoO /epoxide moiety; conver-
sion, selectivity and yield were determined by H NMR spectroscopy.
1
of reaction outcome. In all experiments epoxide trans-2a was
only formed in small amounts ≤2%.
In order to evaluate the substrate scope of the catalyst
system various mono- as well as bis-epoxidized oleo com-
pounds were converted to the corresponding cyclic carbonates
4
3
2
1
4
3
[
4
3
1
3
employing [Bu
mized reaction conditions (Scheme 3). The respective epoxides
were prepared according to the epoxidation protocol men- octyl oleate (cis-2c) were converted into the cyclic carbonates
4 3
P]Br and MoO as catalytic system under opti-
2
tioned above from the respective olefins utilizing hydrogen 3a–3c in high yields of 98%, >99% and 96%, respectively. The
peroxide and a ruthenium-based catalyst system at room tem- cis : trans selectivities of the corresponding carbonated dia-
5
7
perature. In addition to the model substrate epoxidized stereoisomers were quite similar and did not exceed a ratio of
methyl oleate cis-2a the corresponding ethyl (cis-2b) and iso- 77 : 23 for the isomer cis-3a. A distinct trend with regard to the
cis-isomers was observed for all the isolated carbonates 3.
Epoxidized methyl eicosenoate (cis-2d) was isolated in a very
good yield of 83%, however for epoxidized methyl erucate (cis-
2e) a conversion of only 50% was observed under these reac-
tion conditions and 46% of 3e was isolated. Epoxidized methyl
ricinoleate (cis-2f) proved to be a challenging substrate.
Although full conversion of cis-2f was achieved at 100 °C,
50 bar and 20 h, only 42% of cis-2f was selectively converted to
the corresponding carbonate 3f. NMR and GC-MS studies
revealed the formation of a 5-membered ether derivative in
5
7
3
9% yield as a by-product. This isomerization product is
most reasonably formed due to an intramolecular substitution
reaction of the alcohol moiety and the epoxide. However, if the
alcohol moiety was protected by an acetyl group, the yield and
selectivity were increased considerably. Under the given reac-
tion conditions a conversion of 86% was obtained while 63%
of the desired carbonate 3g was isolated. Epoxidized methyl
linoleate (cis-2h) was also employed as a substrate. Consider-
ing the fact that bis-epoxide cis-2h was only converted to 75%
with a selectivity of 89% towards 3h the time was prolonged to
4
0 h to obtain a higher conversion of 88% while the selectivity
Fig. 2 Effect of the reaction time in the coupling reaction of cis-2a and
CO Reaction conditions: 5.0 mmol cis-2a, 2.0 mol% [Bu P]Br,
.25 mol% MoO , p(CO , 100 °C) = 50 bar, 100 °C.
was increased to 93%. Moreover, if the amount of catalyst was
adjusted to 2 mol% [Bu P]Br and 0.25 mol% MoO per
2
.
4
0
3
2
4
3
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oils 6 were employed in technical grade and the catalyst
amount was adjusted in respect to the oxirane number, deter-
1
mined by H NMR with mesitylene as an internal standard.
Epoxidized high-oleic sunflower oil 6a is enriched in epoxi-
dized methyl oleate triglyceride, hence it is akin to the model
substrate cis-2a. Under the optimized reaction conditions full
conversion of 6a was obtained yielding 95% of the corres-
ponding carbonated species 7a (entry 1). The comparison of
the FTIR spectra of substrate 6a and the carbonated oil 7a
Scheme 4 Upscaling of the coupling reaction of 2g and CO
2
to
produce 3g employing two component catalyst system composed of
Bu P]Br and MoO
[
4
3
.
epoxide unit almost full conversion was obtained and an excel- revealed very vividly the specific product band at 1797 cm−1
lent selectivity of 96% was determined after 20 h. Additionally, which corresponds to the ν(C–O) stretching vibration of the
cis- and trans-carbonate diastereoisomers of the mono-carbo- cyclic carbonate (Fig. 3). Likewise to the FTIR investigations
1
nated products 3a–3g could be separated by column chromato- also H NMR studies of both, the product 7a and substrate 6a,
graphy and were analyzed by NMR. We were also interested in reflect that the reaction proceeds smoothly under these con-
an upscaling of the reaction producing carbonated fatty acid ditions. The typical resonances in the range of 3.20 to
esters 3 in a multigram scale as they are considered to be a 2.85 ppm correspond to the epoxide 6a and disappeared in the
potential feedstock for renewable plasticizers for PVC. Carbo- spectra of the product 7a. Accordingly, in the range of 4.65 to
nated O-acetyl methyl ricinoleate (3g) provides a useful 4.10 ppm the specific product resonances appeared, which are
5
0
additional ester moiety, thus enabling additional follow-up in the expected range for cyclic carbonate protons. This is
chemistry. Hence 2g was employed in multigram scale reaction also the typical range for CH -protons of the triglyceride back-
2
(
Scheme 4).
The substrate 2g was delivered by Hobum Oleochemicals in cyclic carbonate 7a resonances.
The oxirane number of 4.02 mmol g− of epoxidized high-
technical grade (purity ∼80%) and an oxirane number of
.55 mmol g− was determined prior to its application. oleic sunflower oil (6a) was relatively low, due to the fact that
Initially, the exothermic coupling reaction of 2g and CO was 6a is enriched on epoxidized oleate which exhibits only one
performed in a 20 g substrate scale in respect to 2g to adapt to epoxide unit per fatty acid ester. In contrast, for epoxidized
bone, thus these additional resonances superimpose with
1
1
3
2
−
1
the reactor infrastructure. After 48 h at 100 °C, p(CO
=
8
2
, 100 °C) sunflower oil (6b) an oxirane number of 7.02 mmol g was
a yield of determined, representing a higher concentration of epoxidized
3% of cyclic carbonate 3g was isolated. Hence, to obtain unsaturated double bonds. As a consequence the potential
4 3
50 bar, 2.0 mol% [Bu P]Br and 0.25 mol% MoO
reasonable yields of the desired product the reaction time amount of fixed CO is almost doubled when using 6b com-
2
needed to be adjusted. Subsequently, the reaction was per- pared to 6a. Under the optimized reaction conditions the
formed in a 200 g scale in respect to 2g. After a reaction time corresponding carbonate 7b was obtained in a yield of 96%
of 5 days a yield of 62% was isolated which corresponds to (entry 2). EPOXOL D65 (6c), an epoxidized triglyceride based
1
45 g of carbonated O-acetyl methyl ricinoleate (3g) as a on soybean oil, was also fully converted and 89% isolated yield
product. Further investigations regarding the scope and limit- on 7c was achieved (entry 3). Carbonated soybean oil is a well
ation of the reaction protocol were conducted employing epoxi- investigated compound, since it is a starting material for non-
dized vegetable oils 6 as substrates (Table 6). The respective isocyanate polyurethanes based on renewables. Very recently,
a
Table 6 Insertion of CO
2
into epoxidized vegetable oils 6 producing the corresponding carbonated oils 7
b
c
Entry
Substrate 6
Carbonate 7
Conversion 6 (%)
Selectivity 7 (%)
Yield 7 (%)
1
2
3
4
5
Epoxidized high-oleic sunflower oil (6a)
Epoxidized sunflower oil (6b)
Epoxidized soybean oil EPOXOL D65 (6c)
Epoxidized linseed oil (6d)
7a
7b
7c
7d
7e
>99
98
99
97
84
95
98
90
79
>99
95
96
89
77
84
Epoxidized methyl soyate (6e)
a
Reaction conditions: 2.0 mol% [Bu
4
P]Br, 0.25 mol% MoO
3 2
, p(CO , 100 °C) = 50 bar, 100 °C, 20 h; conversion und selectivity were determined by
b −1 −1 −1
1
H NMR. The employed epoxidized oils are of technical grade. Oxirane numbers: 6a 4.87 mmol g ; 6b 7.02 mmol g , 6c 4.81 mmol g , 6d
−
1
−1 c
8
.62 mmol g , 6e 4.36 mmol g . Isolated yield after filtration of the reaction mixture.
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1
Fig. 3 FTIR and H NMR spectra of carbonated high-oleic sunflower oil (7a) and the corresponding spectra of the substrate 6a. Characteristic FTIR
−
1
−1
−1
bands in the range of 1600–3000 cm for 7a: 2923 cm (ν(C–H), asymmetric CH
2
stretching vibration), 2854 cm (ν(C–H), symmetric CH
2
−1
−1
stretching vibration), 1797 cm (ν(C–O), stretching vibration of the carbonate groups) and 1739 cm (ν(C–O), stretching vibration of the ester
groups); for 6a: 2916 cm− (ν(C–H), asymmetric CH
ν(C–O), stretching vibration of the ester groups). Characteristic H NMR resonances for 7a: cyclic carbonate –CH– protons δ 4.19–4.24 and
.59–4.64 ppm (triangle), triglyceride –CH
1
−1
−1
2
stretching vibration), 2850 cm (ν(C–H), symmetric CH
2
stretching vibration) and 1732 cm
1
(
1
4
2
– protons δ 4.15 and 4.30 (dot), –CH– 5.23–5.30 (square) ppm; characteristic H NMR resonances for
17,50,51
6
a: epoxide –CH– protons δ 2.85–3.20 ppm (diamond), triglyceride –CH
2
– protons δ 4.15 and 4.30 (dot), –CH– 5.23–5.30 (square) ppm.
Rokicki et al. reported in a very detailed review suitable cata- and MoO to epoxidized vegetable oils 6 of technical grade was
3
lytic systems for the carbonization of epoxidized vegetable smoothly carried out and excellent conversions with selectiv-
1
4
oils. However, to obtain reasonable rates of product for- ities up to >99% were obtained.
mation either high catalyst loadings of up to 5 mol% per
epoxy group and/or drastic reaction conditions up to 180 °C or
1
85 bar CO
2
pressure were required. In contrast to that,
Conclusions
the employed catalyst system [Bu P]Br and MoO showed excel-
4
3
lent results under comparatively mild reaction conditions. In summary, tetra-n-butylphosphonium bromide and molyb-
Among the employed epoxidized vegetable oils, linseed oil 6d denum trioxide were found as a highly active catalyst system
exhibits the highest epoxide content with an oxirane number for the synthesis of oleochemical cyclic carbonates from CO2
of 8.62 mmol g− (entry 4). Almost full conversion was and the corresponding epoxides. MoO3 considerably acceler-
1
obtained, while a good yield of 77% on 7d was isolated. The ated the reaction rate of the organocatalyst [Bu P]Br. The pro-
4
organocatalytic approach for the synthesis of carbonated duced cyclic carbonates were obtained as cis- and trans-
linseed oil was reported recently and involves also an two-com- diastereoisomers and two different ring-closure pathways eluci-
5
1
ponent catalyst system. Detailed kinetic studies revealed opti- date the formation of both products in the proposed mechan-
mized reaction conditions of 120 °C, 5.0 MPa, 10 h, 2.2 mol% ism. Moreover, the stereochemistry can be controlled by the
4
4
[Bu N]Br and 2.2 mol% perfluoro tert-butanol. However, the catalyst, in particular by the halide of the [Bu P]-based catalyst.
reaction time for the [Bu
4
3
4
P]Br and MoO system was longer, Among all tested organocatalysts, [Bu P]Br showed both, high
the carbonated vegetable oil 7d was isolated under less drastic chemoselectivity as well as a high reaction rate. Investigations
reaction conditions in a good yield of 77%. Finally we tested regarding effects of catalyst ratio and concentration, tempera-
NEXO E1, representing methyl ester of soybean oil in technical ture, CO pressure and time on the coupling efficiency revealed
2
grade (entry 5). Under the present reaction conditions a good optimized reaction conditions. Hence, 8 mono- and polyepoxi-
conversion of 84% was detected. An identical yield of 84% rep- dized fatty acid esters were employed to evaluate the scope and
resents excellent carbonate selectivity for NEXO E1 as a sub- limitation of the reaction protocol. High yields of up to >99%
strate. In general, the adaption of the catalytic system [Bu P]Br and selectivities up to >99% were obtained and proved that
4
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this system is very efficient in the coupling reaction. an initial CO
2
pressure of 3.5 MPa was set and the reactor was
However, during the reaction optimization by-products were heated to 100 °C for 20 h while p(CO , 100 °C) was kept con-
2
obtained only in small amounts; only epoxidized methyl rici- stant at 5.0 MPa. Afterwards the reactor was cooled with an ice
2
noleate led to an intramolecular formed by-product. The pro- bath below 20 °C and CO was released slowly. Conversion and
1
tection of alcohol moiety by an acetyl-group enabled good selectivity were determined by H NMR and/or GC from the
conversion and selectivity, too. In addition to epoxidized fatty reaction mixture. The crude product was directly purified by
2
acid methyl esters, 5 epoxidized vegetable oils and derivatives flash chromatography on silica gel (SiO ) employing cyclo-
were employed as substrates. These carbonated oils are con- hexane (cHex)/ethyl acetate (EtOAc) as eluent. All volatiles were
sidered to be a suitable feedstock for the production of non- removed in vacuum to obtain the cyclic carbonate 3.
3
isocyanate polyurethanes. Usually harsh reaction conditions
Synthesis of carbonated oils (GP4). A 45 cm stainless steel
and high catalyst loadings are required to facilitate reasonable autoclave was charged with MoO3 (0.0025 equiv.) and tetra-
reaction rates. Under comparatively mild reaction conditions n-butylphosphonium bromide (0.02 equiv.). After the epoxi-
of 100 °C, p(CO
2 4
, 100 °C) = 50 bar, 20 h and 2.0 mol% [Bu P]Br dized oil 6 (1.0 equiv.) was added dropwise the reactor was
and 0.25 mol% MoO3 per epoxide conversions between immediately sealed and purged with CO . Subsequently, an
2
8
4–99% were obtained while selectivities up to >99% were initial CO
determined. Finally, the coupling reaction of epoxidized heated to 100 °C for 20 h while p(CO
O-acetyl methyl ricinoleate and CO was scaled up to obtain stant at 5.0 MPa. Afterwards the reactor was cooled with an ice
2
pressure of 3.5 MPa was set and the reactor was
2
, 100 °C) was kept con-
2
1
45 g of the desired product in a single batch.
2
bath below 20 °C and CO was released slowly. Conversion and
1
selectivity were determined by H NMR from the reaction
mixture. After the reaction mixture was filtrated over SiO2
employing cyclohexane (cHex)/ethyl acetate (EtOAc) or
dichloromethane (DCM) as eluent all volatiles were removed in
vacuum to obtain the carbonated oils 7.
Experimentals
General procedures (GP)
5
6
Catalyst screening and parameter optimization (GP1). A
cis-Methyl 8-(3-octyloxiran-2-yl)octanoate (cis-2a). Accord-
3
4
5 cm stainless steel autoclave was charged with metal based ing to GP2, methyl oleate (cis-1a, 11.84 g, 39.93 mmol),
co-catalyst (0–0.02 equiv.) and a respective organocatalyst Ru(acac)3 (80 mg, 0.20 mmol), dipicolinic acid (668 mg,
0–0.02 equiv.). After epoxidized methyl oleate (cis-2a, 1.0 4.00 mmol) and hydrogen peroxide (35%, 12.8 g, 132 mmol) in
(
equiv.) was added dropwise the reactor was sealed and acetonitrile (160 mL) were stirred for 4 h at 25 °C. Sub-
immediately purged with CO . Subsequently, the initial reac- sequently, the reaction mixture was extracted with cyclohexane
2
tion pressure was set to 0.2–3.5 MPa and the reactor was (4 × 200 mL), the combined organic layers were concentrated
2 2
heated to 80–120 °C for 4–24 h while p(CO , 100 °C) was kept to 100 mL and washed with H O (100 mL). After removal of all
constant at 0.5–5.0 MPa. Afterwards the reactor was cooled volatiles in vacuum cis-2a (12.08 g, 38.66 mmol, 97%) was
1
with an ice bath below 20 °C and CO
2 3
was released slowly. Con- obtained as a colorless oil. H NMR (300 MHz, CDCl , 22 °C):
3
version, selectivity and yield were determined by GC with a δ = 0.88 (t, JH,H = 6.7 Hz, 3H), 1.23–1.54 (m, 24H), 1.57–1.67
3
flame ionization detector and n-hexadecane as an internal (m, 2H), 2.30 (t, J
standard directly from the reaction mixture.
Epoxidation of fatty acid esters 2 (GP2). The fatty acid ester 1 (CH
= 7.5 Hz, 2H), 2.86–2.92 (m, 2H), 3.66 (s,
3H) ppm; C{ H}NMR (75 MHz, CDCl
H,H
1
3
1
3
, 22 °C): δ = 14.07
), 26.57 (CH ),
3
), 22.63 (CH ), 24.86 (CH ), 26.52 (CH
2
2
2
2
(
1.0 equiv.) was added to a solution of Ru(acac) (0.005–0.010 27.76 (CH ), 27.80 (CH ), 29.00 (CH ), 29.15 (CH ), 29.19
3
2
2
2
2
equiv.) and dipicolinic acid (0.1–0.2 equiv.) in acetonitrile (CH
2
), 29.30 (CH
2
), 29.50 (CH
2
), 29.52 (CH
2
2
), 31.82 (CH ),
(
0.25 M in respect to 1). The resulting suspension was soni- 34.02 (CH
2
), 51.42 (OCH
3
), 57.15 (CH), 57.20 (CH), 174.23
+
cated to obtain
a homogeneous mixture. Subsequently, (CvO) ppm; MS (EI): m/z (%): 281 (1) [M − OCH ], 264 (1),
3
aqueous hydrogen peroxide (35%, 3.3 equiv.) was added in 199 (14), 171 (17), 155 (100), 153 (20), 139 (19), 127 (23), 121
portions and the reaction mixture was allowed to stir for (10), 109 (26), 97 (34), 87 (32), 83 (32), 74 (54), 69 (46), 55 (63),
4
–24 h at 25 °C. The resulting mixture was extracted with cyclo- 43 (29), 41 (35); elemental analysis calcd (%) for C H O
19 36
3
hexane (cHex) and the combined organic layers were concen- (312.49): C 73.03, H 11.61, found: C 73.01, H 11.73.
trated to approximately 1/4 of the initial volume and
subsequently washed with water. The organic phase was dried
Cyclic carbonates
4
9
over MgSO
product 2. If necessary the crude product was purified by flash According to GP3, MoO
chromatography on silica (SiO ) employing cyclohexane (cHex)/ phosphonium bromide (34 mg, 0.10 mmol) and epoxidized
4
and all volatiles were removed in vacuum to yield
Methyl 8-(5-octyl-2-oxo-1,3-dioxolan-4-yl)octanoate (3a).
3
(1.8 mg, 0.013 mmol), tetra-n-butyl-
2
ethyl acetate (EtOAc) as eluent.
Synthesis of carbonated fatty acid esters 3 (GP3). A 45 cm
methyl oleate (cis-2a, 1.56 g, 5.00 mmol) were allowed to react
with CO . The crude product was purified by flash chromato-
3
2
stainless steel autoclave was charged with MoO3 (0.0025 graphy (SiO , cHex : EtOAc = 20 : 1 to 10 : 1) to yield 3a (1.74 g,
2
equiv.) and tetra-n-butylphosphonium bromide (0.02 equiv.). 4.88 mmol, 98%, cis : trans = 77 : 23) as a colorless oil. cis-3a:
1
After the epoxide 2 (1.0 equiv.) was added dropwise the reactor
R
f
= 0.21 (cHex : EtOAc = 10 : 1); H NMR (300 MHz, CDCl
3
,
3
was immediately sealed and purged with CO . Subsequently, 22 °C): δ = 0.88 (t, JH,H = 6.8 Hz, 3H), 1.20–1.44 (m, 18H),
2
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3
1
4
38 5
.46–1.75 (m, 8H), 2.30 (t, JH,H = 7.5 Hz, 2H), 3.67 (s, 3H), (100), 43 (53), 41 (52); HRMS (ESI-TOF): m/z calcd for C21H O
1
3
1
+
.58–4.66 (m, 2H) ppm; C{ H} NMR (75 MHz, CDCl , 22 °C) [M + Na]: 393.2612; found: 393.2612.
3
δ = 14.05 (CH
3
), 22.60 (CH
2
), 24.78 (CH
2
), 25.51 (CH
2
), 25.56
Iso-octyl 8-(5-octyl-2-oxo-1,3-dioxolan-4-yl)octanoate (3c).
(CH
2
), 28.83 (CH
2
), 28.86 (CH
2
), 28.89 (CH
2
), 28.95 (CH
2
), According to GP3, MoO (2.2 mg, 0.015 mmol), tetra-n-butyl-
3
2
8.99 (CH ), 29.11 (CH ), 29.20 (CH ), 29.28 (CH ), 31.75 phosphonium bromide (41 mg, 0.12 mmol) and epoxidized
2
2
2
2
(
1
CH
2
), 33.96 (CH
2
), 51.45 (OCH
3
), 79.88 (CH), 79.93 (CH), iso-octyl oleate (cis-3c, 1.50 g, 3.69 mmol) were allowed to react
. The crude product was purified by flash chromato-
54.75 (CvO), 174.18 (CvO) ppm; MS (EI): m/z (%): 357 (1) with CO
2
+
[M + H], 325 (34), 294 (9), 262 (20), 239 (64), 221 (10), 181 (13), graphy (SiO , cHex : EtOAc = 1 : 1) to yield 3c (1.61 g,
2
1
6
64 (16), 155 (38), 135 (26), 121 (34), 109 (47), 95 (77), 81 (78), 3.54 mmol, 96%, cis : trans = 62 : 38) as a colorless oil. cis-3c: R
f
1
3
9 (59), 55 (100), 43 (56), 41 (56); HRMS (EI): m/z calcd for = 0.42 (cHex : EtOAc = 5 : 1); H NMR (300 MHz, CDCl , 22 °C):
+
C H O [M + H]: 357.2636; found: 357.2634; trans-3a: R = δ = 0.87–0.92 (m, 9H), 1.22–1.46 (m, 26H), 1.46–1.78 (m, 9H),
0
δ = 0.85 (t, JH,H = 6.8 Hz, 3H), 1.19–1.50 (m, 20H), 1.54–1.75 2H) ppm; C{ H} NMR (75 MHz, CDCl , 22 °C): δ = 10.96
3
2
0
36
5
f
1
3
3
.12 (cHex : EtOAc = 10 : 1); H NMR (300 MHz, CDCl , 22 °C): 2.31 (t, JH,H = 7.5 Hz, 2H), 3.94–4.04 (m, 2H), 4.59–4.65 (m,
3
13
1
3
(m, 6H), 2.28 (t, J
= 7.5 Hz, 2H), 3.64 (s, 3H), 4.17–4.24 (m, (CH ), 14.02 (CH ), 14.05 (CH ), 22.60 (CH ), 22.94 (CH ),
H,H
3
3
3
2
2
1
3
1
2
H) ppm; C{ H} NMR (75 MHz, CDCl
3
, 22 °C): δ = 13.97 23.75 (CH
2
), 24.88 (CH
2
), 25.54 (CH
2
), 25.57 (CH
2
), 28.84
(CH
3
), 22.50 (CH ), 24.48 (CH ), 24.52 (CH ), 24.69 (CH ), (CH ), 28.87 (2 × CH ), 28.94 (CH ), 28.99 (CH ), 29.03 (CH ),
2
2 2 2 2 2 2 2 2
2
8.79 (CH ), 28.84 (2 × CH ), 29.00 (CH ), 29.05 (CH ), 29.19 29.11 (CH ), 29.21 (CH ), 29.29 (CH ), 30.37 (CH ), 31.76
2
2
2
2
2
2
2
2
(CH
2
), 31.66 (CH
2
), 33.67 (CH
2
), 33.68 (CH
2
), 33.85 (CH
2
), (CH
2
), 34.30 (CH
2
), 38.69 (CH), 66.64 (CH
2
), 79.88 (CH), 79.92
5
3
1.34 (OCH ), 81.87 (CH), 81.91 (CH), 154.60 (CvO), 174.05 (CH), 154.74 (CvO), 173.96 (CvO) ppm; MS (EI): m/z (%): 343
+
(
(
(
(
CvO) ppm; MS (EI): m/z (%): 357 (1) [M + H], 325 (35), 294 (1), 325 (100), 239 (9), 155 (11), 112 (22), 109 (14), 97 (15), 95
7), 262 (17), 241 (25), 239 (32), 221 (18), 181 (11), 164 (14), 155 (21), 83 (26), 81 (22), 71 (27), 67 (16), 57 (42), 55 (38), 43 (25),
24), 135 (25), 121 (34), 109 (55), 95 (86), 81 (83), 69 (60), 55 41 (20); HRMS (ESI-TOF): m/z calcd for C27
100), 43 (55), 41 (56); HRMS (ESI-TOF): m/z calcd for C H O
+
H
50
O
5
[M + H]:
455.3731; found: 455.3731; trans-3c: R = 0.50 (cHex : EtOAc =
2
0
36
5
f
+
1
[
M + H]: 357.2636; found: 357.2634.
Ethyl 8-(5-octyl-2-oxo-1,3-dioxolan-4-yl)octanoate
According to GP3, MoO (0.6 mg, 0.0042 mmol), tetra-n-butyl- 7.4 Hz, 2H), 3.93–4.03 (m, 2H), 4.19–4.26 (m, 2H) ppm;
10 : 1); H NMR (300 MHz, CDCl
(3b). 9H), 1.22–1.48 (m, 28H), 1.51–1.79 (m, 7H), 2.30 (t,
3
, 22 °C): δ = 0.86–0.91 (m,
3
J
H,H
=
C
1
3
3
1
phosphonium bromide (13 mg, 0.038 mmol) epoxidized ethyl { H} NMR (75 MHz, CDCl
oleate (cis-2b, 600 mg, 1.84 mmol) were allowed to react with (CH ), 14.05 (CH ), 22.59 (CH
3
, 22 °C): δ = 10.96 (CH
3
), 14.02
),
3
3
2
), 22.94 (CH ), 23.75 (CH
2
2
CO . The crude product was purified by flash chromatography 24.60 (CH ), 24.87 (CH ), 28.88 (CH ), 28.92 (CH ), 28.97 (2 ×
2
2
2
2
2
(SiO
2
, cHex : EtOAc = 20 : 1 to 10 : 1) to yield 3b (680 mg, CH
2
), 29.09 (CH
2
), 29.14 (CH
2
), 29.27 (CH
2
2
), 30.37 (CH ), 31.50
1
2 2 2 2
.84 mmol, >99%, cis : trans = 65 : 35) as a colorless oil. cis-3b: (CH ), 31.75 (CH ), 33.79 (2 × CH ), 34.29 (CH ), 38.70 (CH),
1
R = 0.50 (cHex : EtOAc = 10 : 1); H NMR (300 MHz, CDCl3, 66.64 (CH ), 81.95 (CH), 81.99 (CH), 154.69 (CvO), 173.94
f
2
3
2
1
7
2 °C): δ = 0.88 (t,
.47–1.74 (m, 8H), 2.29 (t, JH,H = 7.5 Hz, 2H), 4.12 (q, JH,H
.1 Hz, 2H), 4.58–4.66 (m, 2H) ppm; C{ H} NMR (75 MHz, 71 (25), 67 (17), 57 (40), 55 (38), 43 (26), 41 (21); HRMS
J
H,H = 6.8 Hz, 3H), 1.23–1.43 (m, 21H), (CvO) ppm; MS (EI): m/z (%): 343 (1), 325 (100), 239 (4), 155
3
3
=
(5), 123 (9), 112 (21), 109 (15), 97 (14), 95 (22), 83 (25), 81 (21),
1
3
1
+
3 3 3 2 50 5
CDCl , 22 °C): δ = 14.05 (CH ), 14.22 (CH ), 22.60 (CH ), 24.81 (ESI-TOF): m/z calcd for C27H O [M + H]: 455.3731; found:
(
2
CH
2
), 25.52 (CH
2
), 25.57 (CH
2
), 28.84 (CH
2
), 28.86 (CH
2
), 455.3731.
Methyl 10-(5-octyl-2-oxo-1,3-dioxolan-4-yl)decanoate (3d).
), According to GP3, MoO (1.1 mg, 0.0076 mmol), tetra-n-butyl-
8.90 (CH ), 28.96 (CH ), 29.00 (CH ), 29.11 (CH ), 29.21
2
2
2
2
(CH
2
), 29.29 (CH
2
), 31.76 (CH
2
), 34.24 (CH
2
), 60.17 (OCH
2
3
7
9.88 (CH), 79.93 (CH), 154.75 (CvO), 173.76 (CvO) ppm; MS phosphonium bromide (20 mg, 0.059 mmol) and epoxidized
+
(EI): m/z (%): 325 (50) [M − OEt], 262 (17), 241 (14), 239 (47), methyl eicosenoate (cis-2d, 1.00 g, 2.94 mmol) were allowed to
2
21 (8), 171 (16), 164 (12), 155 (35), 149 (16), 135 (23), 123 (28), react with CO
2
. The crude product was purified by flash
1
21 (31), 109 (51), 95 (79), 81 (80), 69 (63), 67 (58), 55 (100), 43 chromatography (SiO
2
, cHex : EtOAc = 20 : 1 to 10 : 1) to yield
+
(50), 41 (49); HRMS (ESI-TOF): m/z calcd for C H O [M + 3d (940 mg, 2.44 mmol, 83%, cis : trans = 77 : 23) as a colorless
2
1
38 5
1
Na]: 393.2612; found: 393.2612; trans-3b: R
f
= 0.42 (cHex : oil. cis-3d: R
f
= 0.66 (cHex : EtOAc = 2 : 1); H NMR (300 MHz,
1
3
EtOAc = 10 : 1); H NMR (300 MHz, CDCl
3
, 22 °C): δ = 0.88 (t, CDCl
3
, 22 °C): δ = 0.89 (t, JH,H = 6.7 Hz, 3H), 1.20–1.44 (m,
3
3
J
= 6.8 Hz, 3H), 1.23–1.53 (m, 23H), 1.57–1.78 (m, 6H), 2.29 22H), 1.46–1.78 (m, 8H), 2.31 (t, J
= 7.5 Hz, 2H), 3.67 (s,
H,H
3
H,H
3
13
1
3
(t, JH,H = 7.5 Hz, 2H), 4.12 (q, JH,H = 7.1 Hz, 2H), 4.19–4.26 3H), 4.58–4.69 (m, 2H) ppm; C{ H} NMR (75 MHz, CDCl ,
1
3
1
3 3 2 2
(m, 2H) ppm; C{ H} NMR (75 MHz, CDCl , 22 °C): δ = 14.05 22 °C): δ = 14.06 (CH ), 22.61 (CH ), 24.88 (CH ), 25.57 (2 ×
(
CH ), 14.22 (CH ), 22.59 (CH ), 24.57 (CH ), 24.60 (CH ), CH ), 28.86 (2 × CH ), 29.05 (CH ), 29.12 (2 × CH ), 29.18
3
3
2
2
2
2
2
2
2
2
4.80 (CH
2
), 28.87 (CH
2
), 28.94 (2 × CH
2
), 29.08 (CH
2
), 29.14 (CH
2
), 29.22 (2 × CH
2
), 29.25 (CH
2
), 29.30 (CH
2
2
), 31.76 (CH ),
(
6
(
(
(
CH
2
), 29.27 (CH
2
), 31.74 (CH
2
), 33.78 (2 × CH
2
), 34.23 (CH
2
), 34.04 (CH
2
), 51.43 (OCH ), 79.93 (2 × CH), 154.77 (CvO),
3
+
0.17 (OCH ), 81.95 (CH), 81.99 (CH), 154.69 (CvO), 173.74 174.27 (CvO) ppm; MS (EI): m/z (%): 353 (40) [M − OMe], 267
2
+
CvO) ppm; MS (EI): m/z (%): 341 (1) [M − OEt], 325 (29), 241 (53), 249 (14), 225 (23), 155 (30), 149 (18), 135 (25), 123 (28),
12), 239 (15), 221 (9), 207 (20), 155 (15), 149 (10), 135 (16), 123 109 (40), 98 (100), 95 (70), 87 (19), 81 (69), 74 (34), 69 (63), 55
25), 121 (24), 109 (47), 95 (72), 81 (73), 69 (59), 67 (54), 55 (90), 43 (55), 41 (53); HRMS (ESI-TOF): m/z calcd for C H O
40 5
2
2
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+
1
[
M + H]: 385.2949; found: 385.2945; trans-3d: R
f
= 0.76 (cHex :
f 3
R = 0.08 (cHex : EtOAc = 2 : 1); H NMR (300 MHz, CDCl ,
1
3
EtOAc = 2 : 1); H NMR (300 MHz, CDCl , 22 °C): δ = 0.89 (t, 22 °C): δ = 0.88 (t, JH,H = 6.5 Hz, 3H), 1.20–1.67 (m, 22H),
3
3
3
J
H,H = 6.8 Hz, 3H), 1.20–1.54 (m, 24H), 1.56–1.80 (m, 6H), 2.31 1.68–1.94 (m, 2H), 2.00–2.12 (m, 1H), 2.30 (t, JH,H = 7.5 Hz,
3
(
t, JH,H = 7.5 Hz, 2H), 3.67 (s, 3H), 4.19–4.26 (m, 2H) ppm; 2H), 3.66 (s, 3H) 3.77–3.89 (m, 1H), 4.63–4.69 (m, 1H),
1
3
1
C{ H} NMR (75 MHz, CDCl , 22 °C): δ = 14.05 (CH ), 22.59 4.83–4.90 (m, 1H, isomer 1), 4.96–5.03 (m, 1H, isomer 2) ppm;
CH
3
3
1
3
1
(
2
), 24.61 (2 × CH
), 29.13 (2 × CH
2
), 24.87 (CH
2
), 29.04 (CH
2
), 29.10 (2 ×
C{ H} NMR (75 MHz, CDCl
3
, 22 °C): as a mixture of two dia-
), 22.51 (2 × CH ),
CH
2
2
), 29.20 (CH
2
), 29.23 (CH
2
), 29.27 (CH
2
), stereomers (dr = 60 : 40) δ = 13.99 (2 × CH
3
2
3
1.75 (CH ), 33.80 (2 × CH ), 34.03 (CH ), 51.43 (OCH ), 81.99 24.73 (2 × CH ), 25.28 (CH ), 25.34 (CH ), 25.38 (2 × CH ),
2
2
2
3
2
2
2
2
2
2
(2 × CH), 154.72 (CvO), 174.26 (CvO) ppm; MS (EI): m/z (%): 28.83 (2 × CH
2
), 28.89 (4 × CH
2
), 28.99 (CH
2
), 29.06 (CH
), 35.78 (CH
),
),
+
3
53 (42) [M − OMe], 267 (20), 249 (23), 225 (32), 155 (17), 149 29.10 (2 × CH
2
), 31.69 (2 × CH
2
), 33.93 (2 × CH
2
(
(
17), 135 (13), 123 (34), 109 (45), 98 (100), 95 (74), 87 (18), 81 36.05 (CH ), 36.96 (CH ), 38.22 (CH ), 51.42 (2 × OCH ), 67.60
2 2 2 3
72), 74 (32), 69 (60), 55 (85), 43 (51), 41 (51); HRMS (ESI-TOF): (CH), 69.07 (CH), 76.94 (CH), 77.82 (CH), 79.90 (2 × CH),
+
m/z calcd for C22
Methyl 12-(5-octyl-2-oxo-1,3-dioxolan-4-yl)dodecanoate (3e). m/z (%): 341 (1) [M − OMe], 323 (10), 287 (8), 255 (100), 237
According to GP3, MoO (0.5 mg, 0.0035 mmol), tetra-n-butyl- (19), 226 (21), 211 (13), 193 (11), 164 (49), 155 (17), 135 (17),
H
40
O
5
[M + H]: 385.2949; found: 385.2946.
154.38 (CvO), 154.71 (CvO), 174.21 (2 × CvO) ppm; MS (EI):
+
3
phosphonium bromide (9 mg, 0.03 mmol) and epoxidized 121 (19), 113 (17), 109 (15), 98 (27), 97 (27), 83 (23), 81 (38), 74
methyl erucate (2e, 460 mg, 1.25 mmol) were allowed to react (17), 69 (29), 67 (26), 57 (22), 55 (70), 43 (34), 41 (30); HRMS
+
with CO
graphy (SiO
0
2
. The crude product was purified by flash chromato- (EI): m/z calc. for C20
, cHex : EtOAc = 20 : 1) to yield 3e (238 mg, 373.2579; trans-3f: R
H
36
O
6
[M + H]: 373.2585; found:
1
2
f
= 0.25 (cHex : EtOAc = 2 : 1); H NMR
.577 mmol, 46%, cis : trans = 67 : 33) as a colorless oil; cis–3e: (300 MHz, CDCl , 22 °C): δ = 0.89 (t, JH,H = 6.6 Hz, 3H),
1.23–1.96 (m, 25H), 2.31 (t, JH,H = 7.4 Hz, 2H), 3.67 (s, 3H),
2 °C): δ = 0.88 (t, JH,H = 6.8 Hz, 3H), 1.20–1.43 (m, 26H), 3.74–3.85 (m, 1H), 4.23–4.58 (m, 2H) ppm; C{ H} NMR
3
3
1
3
R
f
= 0.63 (cHex : EtOAc = 2 : 1); H NMR (300 MHz, CDCl
3
,
3
13
1
2
1
4
3
.47–1.75 (m, 8H), 2.30 (t, JH,H = 7.5 Hz, 2H), 3.66 (s, 3H), (75 MHz, CDCl , 22 °C): δ = 14.01 (CH ), 22.53 (CH ), 24.49
3
3
2
1
3
1
.58–4.66 (m, 2H) ppm; C{ H} NMR (75 MHz, CDCl
3
, 22 °C): (CH
2
), 24.76 (CH
2
), 25.37 (CH
2
), 28.80 (CH
2
2
), 28.84 (2 × CH ),
δ = 14.05 (CH
3
), 22.60 (CH
2
), 24.90 (CH
2
), 25.56 (2 × CH
2
2
), 29.12 (CH
2
), 31.70 (CH
2
2 2
), 33.55 (CH ), 33.95 (CH ), 37.58
2
2
8.86 (2 × CH ), 29.09 (CH ), 29.11 (CH ), 29.20 (3 × CH ), (CH ), 40.20 (CH ), 51.46 (OCH ), 68.21 (CH), 79.79 (CH),
2
2
2
2
2
3
9.29 (CH
2
), 29.31 (CH
2
), 29.35 (CH
2
), 29.40 (CH
), 79.94 (2 × CH), (%): 323 (6), 287 (10), 255 (100), 226 (10), 164 (26), 121 (12),
54.77 (CvO), 174.29 (CvO) ppm; MS (EI): m/z (%): 381 (26) 113 (14), 109 (11), 98 (18), 83 (17), 81 (30), 74 (13), 69 (22), 67
2
), 29.44 82.00 (CH), 154.57 (CvO), 174.23 (CvO) ppm; MS (EI): m/z
2 2 2 3
(CH ), 31.76 (CH ), 34.06 (CH ), 51.40 (OCH
1
+
[M − OMe], 295 (27), 277 (10), 253 (12), 239 (15), 155 (21), 137 (20), 55 (51), 43 (25), 41 (21); HRMS (EI): m/z calcd for
+
(
(
(
4
(
13), 123 (21), 112 (36), 109 (34), 98 (100), 95 (58), 87 (17), 83
46), 81 (54), 74 (31), 69 (52), 55 (37), 43 (43), 41 (38); HRMS
ESI-TOF): m/z calc. for C24
13.3258; trans-3e: R
300 MHz, CDCl , 22 °C): δ = 0.89 (t, JH,H = 6.8 Hz, 3H), 0.053 mmol) and epoxidized O-acetylricinoleic acid methyl
C
20
H
36
O
6
[M + H]: 373.2585; found: 373.2587.
Methyl
8-(5-((2R)-acetoxyoctyl)-2-oxo-1,3-dioxolan-4-yl)-
+
H
44
O
5
[M + H]: 413.3262; found: octanoate (3g). According to GP3, MoO
3
(1.0 mg,
1
f
= 0.74 (cHex : EtOAc = 2 : 1); H NMR 0.006.9 mmol), tetra-n-butylphosphonium bromide (18 mg,
3
3
3
1
2
.20–1.60 (m, 28H), 1.61–1.80 (m, 6H), 2.31 (t, JH,H = 7.5 Hz, ester (2g, 1.01 g, 2.73 mmol) were allowed to react with CO .
1
3
1
2
H), 3.67 (s, 3H), 4.19–4.26 (m, 2H) ppm; C{ H} NMR The crude product was purified by flash chromatography
(
75 MHz, CDCl , 22 °C): δ = 14.06 (CH ), 22.60 (CH ), 24.62 (2 (SiO , cHex : EtOAc = 5 : 1) to yield 3g (472 mg, 1.73 mmol,
3
3
2
2
×
CH
2
), 24.91 (CH
2
), 29.10 (2 × CH
), 29.35 (CH ), 29.39 (CH
1.76 (CH ), 33.81 (2 × CH ), 34.07 (CH ), 51.42 (OCH ), 82.00 two diastereoisomers (dr = 60 : 40); R = 0.16 (cHex : EtOAc =
2
), 29.14 (2 × CH
2
), 29.20 63%, cis : trans = 74 : 26) as a colorless oil as a mixture of four
(CH
2
), 29.30 (2 × CH
2
2
2 2
), 29.45 (CH ), diastereoisomers (dr = 44 : 30 : 14 : 12). cis-3g: as a mixture of
3
2
2
2
3
f
1
3
(
3
(
(
2 × CH), 154.73 (CvO), 174.31 (CvO) ppm; MS (EI): m/z (%): 5 : 1); H NMR (300 MHz, CDCl
3
, 22 °C): δ = 0.88 (t, JH,H = 6.7
81 (28) [M − OMe], 295 (12), 277 (15), 253 (6), 239 (7), 155 Hz, 3H), 1.20–1.38 (m, 15H), 1.42–1.70 (m, 5H), 1.73–2.01 (m,
11), 137 (15), 123 (24), 112 (35), 109 (37), 98 (100), 95 (60), 87 2H), 2.05 (s, 3H, isomer 1), 2.07 (s, 3H, isomer 2), 2.30 (t,
+
3
16), 83 (45), 81 (55), 74 (30), 69 (50), 55 (69), 43 (40), 41 (36);
JH,H = 7.5 Hz, 2H), 3.66 (s, 3H), 4.59–4.77 (m, 2H,) 4.96–5.04
+
13
1
44 5 3
HRMS (ESI-TOF): m/z calcd for C24H O [M + H]: 413.3262; (m, 1H) ppm; C{ H} NMR (75 MHz, CDCl , 22 °C): δ = 13.99
found: 413.3256.
(2 × CH ), 21.07 (CH ,), 21.13 (CH ), 22.49 (2 × CH ), 24.76 (2 ×
3
3
3
2
Methyl
8-(5-((2R)-hydroxyoctyl)-2-oxo-1,3-dioxolan-4-yl)- CH
2
), 24.94 (CH
2
), 25.16 (CH
2
), 25.33 (CH
2
2
,), 25.46 (CH ),
octanoate (3f). According to GP3, MoO
3
2 2 2
(1.1 mg, 28.88 (2 × CH ), 28.94 (4 × CH ), 28.99 (2 × CH ), 29.03 (2 ×
0
0
3
.0076 mmol), tetra-n-butylphosphonium bromide (21 mg, CH ), 31.60 (2 × CH ), 33.25 (CH ), 33.59 (CH ), 33.94 (2 ×
2
2
2
2
.062 mmol) and epoxidized methyl ricinoleate (2f, 1.01 g, CH
.07 mmol) were allowed to react with CO
2
), 34.09 (CH
2
), 34.59 (CH
2
3
), 51.43 (2 × OCH ), 70.71 (CH),
2
. The crude product 70.91 (CH), 76.41 (CH), 76.84 (CH), 79.51 (CH), 79.65 (CH),
was purified by flash chromatography (SiO , cHex : EtOAc = 154.19 (CvO), 154.26 (CvO), 170.35 (CvO), 170.88 (CvO),
2
+
2
2
0 : 1 to 5 : 1) to yield 3f (472 mg, 1.27 mmol, 42%, dr = 174.15 (2 × CvO) ppm; MS (EI): m/z (%): 383 (1) [M − OMe],
6 : 39 : 35) as a colorless oil as a mixture of three diastereo- 341 (9), 323 (9), 292 (11), 287 (31), 258 (12), 255 (45), 225 (13),
isomers. cis-3f: as a mixture of two diastereomers (dr = 60 : 40); 167 (24), 164 (17), 150 (10), 135 (16), 121 (21), 113 (37),
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1
(
09 (18), 98 (29), 95 (37), 83 (30), 81 (50), 74 (19), 69 (36), 67 as a pale yellow oil. 7a: H NMR (300 MHz, CDCl
3
, 22 °C): δ =
3
38), 57 (19), 55 (69), 43 (100), 41 (27); HRMS (ESI-TOF): m/z 0.86–0.91 (m, 9H), 1.25–1.73 (m, 78H), 2.32 (t, J
calcd for C22H O [M + H]: 415.2690; found: 415.2692; trans- 6H), 4.15 (dd, JH,H = 11.9 Hz, JH,H = 5.9 Hz, 2H), 4.19–4.24
38 7
= 7.5 Hz,
H,H
+
2
3
2
3
3
g: as a mixture of two diastereoisomers (dr = 52 : 48); R
f
= 0.21 (m, 2H), 4.30 (dd,
J
H,H = 11.9 Hz,
JH,H = 4.3 Hz, 2H),
1
13
1
(
0
6
cHex : EtOAc = 5 : 1); H NMR (300 MHz, CDCl , 22 °C): δ = 4.59–4.64 (m, 3H), 5.23–5.30 (m, 1H) ppm; C{ H} NMR
3
3
.87 (t, JH,H = 6.7 Hz, 3H), 1.20–1.50 (m, 16H), 1.53–1.75 (m, (75 MHz, CDCl
H), 1.79–2.03 (m, 2H), 2.06 (s, 3H, isomer 1), 2.06 (s, 3H, signals, CH ), 62.05 (OCH
= 7.5 Hz, 2H), 3.66 (s, 3H), 4.20–4.35 (CH), 81.95 (CH), 82.00 (CH), 154.67 (CvO), 154.73 (CvO),
3
, 22 °C): δ = 14.05 (CH
3
), 22.59–34.06 (multiple
2
2
), 68.87 (CH), 79.87 (CH), 79.93
3
isomer 2), 2.30 (t, J
(
H,H
1
3
1
m, 2H), 4.95–5.04 (m, 1H) ppm; C{ H} NMR (75 MHz, 172.72 (CvO), 173.12 (CvO) ppm; ATR IR: νmax = 2923 (m),
CDCl , 22 °C): δ = 14.01 (2 × CH ), 21.09 (2 × CH ), 22.47 (2 × 2854 (m), 1797 (vs, CvO), 1739 (s, CvO), 1165 (m), 1038 (m)
3
3
3
−
1
CH ), 24.57 (CH ), 24.61 (CH ), 24.75 (2 × CH ), 24.89 (CH ), cm
5.12 (CH
1.58 (2 × CH
.
2
2
2
2
2
2
2
2
3
3
(
(
(
2
), 28.85 (2 × CH
2
), 28.90 (4 × CH
2
), 28.95 (2 × CH
),
Carbonated sunflower oil (7b). According to GP4, MoO
3
), (4.0 mg, 0.028 mmol), tetra-n-butylphosphonium bromide
2
), 33.42 (2 × CH
2
), 33.93 (2 × CH
2
), 34.14 (CH
4.40 (CH ), 38.10 (CH ), 38.39 (CH ), 51.43 (2 × OCH ), 70.30 (72 mg, 0.21 mmol) and epoxidized sunflower oil (6b, oxirane
2
2
2
3
CH), 70.75 (CH), 78.90 (CH), 79.05 (CH), 81.92 (CH), 81.92 number = 7.02 mmol g− , 1.50 g, 10.5 mmol) were converted
CH), 154.18 (CvO), 154.28 (CvO), 170.39 (CvO), 170.69 with CO . After filtration (SiO , cHex : EtOAc = 1 : 1) the carbo-
CvO), 174.14 (2 × CvO) ppm; MS (EI): m/z (%): 383 (1) [M − nated product (1.93 g) was isolated as a mixture of carbonate
1
2
2
+
1
OMe], 341 (5), 323 (8), 287 (25), 255 (52), 167 (13), 164 (11), 135 7b (96%) and 6b (2%) as a brown solid. 7b: H NMR (300 MHz,
(
(
14), 121 (18), 113 (40), 109 (18), 98 (24), 95 (35), 83 (27), 81 CDCl
3
, 22 °C): δ = 0.84–0.93 (m, 9H), 1.21–2.09 (m, 76H),
2
3
50), 74 (18), 69 (35), 67 (37), 57 (19), 55 (66), 43 (100), 41 (28); 2.28–2.33 (m, 6H), 4.14 (dd, J
= 11.9 Hz, J
= 5.9 Hz,
H,H
H,H
+
38 7
HRMS (EI): m/z calcd for C22H O [M + H]: 415.2690; found: 2H), 4.24–4.31 (m, 3H), 4.41–4.95 (m, 7H), 5.21–5.29 (m, 1H)
4
1
3
1
15.2691.
3
ppm; C{ H} NMR (75 MHz, CDCl , 22 °C): δ = 13.82–14.04
Methyl 8-(2-oxo-5-((2-oxo-5-pentyl-1,3-dioxolan-4-yl)methyl)- (multiple signals, CH ), 19.09–34.01 (multiple signals, CH ),
3
2
4
8
1
0
0
2
2
,3-dioxolan-4-yl)octanoate (3h). According to GP3, (0.7 mg, 62.01 (CH ), 68.85 (CH), 75.28–81.99 (multiple signals, CH),
.0049 mmol), tetra-n-butylphosphonium bromide (14 mg, 153.74 (CvO) 154.71 (CvO), 172.66 CvO), 173.06 CvO); ATR
.041 mmol) and epoxidized methyl linoleate (2h, 653 mg, IR: νmax = 2923 (m), 2836 (m), 1795 (vs, CvO), 1739 (s, CvO),
1
.00 mmol) were allowed to react with CO
2
. The crude product 1167 (m), 1046 (m), 773 (m) cm−
.
7
0
was purified by flash chromatography (SiO
0 : 1) to yield 3h (681 mg, 1.64 mmol, 82%) as a colorless oil (2.0 mg, 0.014 mmol), tetra-n-butylphosphonium bromide
as a mixture of four diastereroisomers (dr = 14 : 16 : 35 : 35). (41 mg, 0.12 mmol) and EPOXOL D65 (6c, oxirane number =
2
, cHex : EtOAc =
Carbonated EPOXOL D65 (7c). According to GP4, MoO
3
1
1
−1
R
f
= 0.08 (cHex : EtOAc = 5 : 1); H NMR (300 MHz, CDCl
3
,
2
4.81 mmol g , 1.04 g, 5.00 mmol) were converted with CO .
2
2 °C): δ = 0.89–0.93 (m, 3H), 1.26–1.45 (m, 12H), 1.52–1.79 After filtration (SiO , cHex/EtOAc = 1 : 1) the carbonated
2
3
(m, 8H), 1.83–2.08 (m, 2H), 2.31 (t, JH,H = 7.5 Hz, 2H), 3.67 (s, product (1.13 g) was isolated as a mixture of carbonate 7c
1
3
4
H), 4.27–4.43 (m, 2H, isomer 1), 4.41–4.52 (m, 2H, isomer 2), (89%) and 6c (<1%) as a yellow oil. 7c: H NMR (300 MHz,
.71–4.78 (m, 2H, isomer 3), 4.86–4.96 (m, 2H, isomer 4) ppm; CDCl , 22 °C): δ = 0.82–0.89 (m, 9H), 1.20–1.74 (m, 73H),
3
1
3
1
C{ H} NMR (75 MHz, CDCl
3
, 22 °C): δ = 13.85 (CH
3
), 22.31 2.29–2.35 (m, 6H), 4.08–4.14 (m, 2H), 4.24–4.28 (m, 2H),
), 24.35 (2 × CH ), 25.27 (CH ), 4.29–4.93 (m, 8H), 5.19–5.26 (m, 1H) ppm; C{ H} NMR
1
3
1
(CH
2
), 22.33 (CH
2
), 24.10 (CH
2
2
2
2
2
5.43 (CH ), 25.54 (2 × CH ), 24.73 (CH ), 28.84 (2 × CH ), (75 MHz, CDCl , 22 °C) δ = 13.78 (CH ), 13.97 (CH ), 13.99
2
2
2
2
3
3
3
8.89 (CH
2
), 28.95 (2 × CH
2
), 31.19 (CH
2
), 31.22 (CH
2
3 2 2
), 33.32 (CH ) 22.25–33.91 (multiple signals, CH ), 61.97 (CH ), 68.81
(CH
2
), 33.40 (CH ), 33.93 (CH ), 34.02 (CH ), 51.45 (OCH ), (CH), 75.42 (CH), 79.36 (CH), 79.89 (CH), 81.96 (CH), 153.74
2 2 2 3
7
7
1
1
3
8
5.22 (CH), 75.35 (CH), 77.59 (CH), 77.64 (CH), 79.24 (CH), (CvO), 154.68 (CvO), 172.63 (CvO), 173.03 (CvO), 173.18
9.35 (CH), 79.40 (CH), 81.90 (CH), 81.96 (CH), 82.07 (CH), (CvO); ATR IR: νmax = 2924 (m), 2854 (m), 1794 (vs, CvO),
−
1
53.64 (CvO), 153.66 (CvO), 153.70 (CvO), 153.72 (CvO), 1738 (s), 1170 (m), 1046 (m), 773 (m) cm
74.16 (CvO) ppm; MS (EI): m/z (%): 383 (13) [M − OMe],
.
6
9
+
51
Carbonated linseed oil (7d). According to GP4, MoO3
20 (9), 151 (26), 121 (18), 109 (21), 107 (21), 95 (45), 84 (49), (4.7 mg, 0.033 mmol), tetra-n-butylphosphonium bromide
1 (57), 74 (26), 69 (42), 67 (46), 55 (100), 44 (74), 41 (61); (88 mg, 0.26 mmol) and epoxidized linseed oil (6d, oxirane
+
−1
HRMS (EI): m/z calcd for C H O [M + H]: 415.2326; found: number = 8.62 mmol g , 1.51 g, 13.0 mmol) were converted
2
1
34 8
4
15.2329.
2 2
with CO . After filtration (SiO , cHex/EtOAc = 1 : 1) the carbo-
nated product (1.65 g) was isolated as a mixture of carbonate
Carbonated oils
Carbonated high-oleic sunflower oil (7a). According to GP4, CDCl
MoO (2.5 mg, 0.017 mmol), tetra-n-butylphosphonium 1.22–2.14 (m, 68H), 2.27–2.31 (m, 6H), 4.10 (dd, J = 11.8 Hz,
bromide (48 mg, 0.14 mmol) and epoxidized high-oleic sun- 5.9 Hz, 2H), 4.20–4.35 (m, 3H), 4.39–5.06 (m, 10H); 5.21–5.24
1
7
d (77%) and 6d (3%) as a yellow oil. 7d: H NMR (300 MHz,
3
, 22 °C): δ = 0.83–0.90 (m, 5H), 1.02–1.08 (m, 4H),
3
−
1
13
1
flower oil (6a, oxirane number = 4.71 mmol g , 1.51 g, (m, 1H); C{ H} NMR (75 MHz, CDCl
.07 mmol) were converted with CO . After filtration (SiO 10.39 (CH ), 10.51 (CH ), 13.79 (CH
CH Cl ) the carbonated product 7a (1.73 g, 95%) was isolated (CH ), 22.10–33.96 (multiple signals, CH ), 61.95 (CH ), 68.78
3
, 22 °C) δ = 9.98 (CH
3
),
7
2
2
,
3
3
3
), 13.97 (CH ), 14.00
3
2
2
3
2
2
Green Chem.
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Paper
(
(
(
(
CH), 75.47 (CH), 79.47–81.97 (multiple signals, CH), 153.83
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CvO), 153.93 (CvO), 154.73 (CO ), 172.67 (CvO), 173.06
3
CvO), 173.13 (CvO); ATR IR: νmax = 2924 (m), 2854 (m), 1790
−
1
vs, CvO), 1737 (s), 1171 (m), 1034 (m), 773 (m) cm
.
2
0
Carbonated methyl soyate NEXO E1 (7e). According to
3
GP4, MoO (2.4 mg, 0.017 mmol), tetra-n-butylphosphonium 11 M. R. g. Klaas and S. Warwel, in Recent Developments in the
bromide (44 mg, 0.13 mmol) and methyl soyate NEXO E1 (6e,
Synthesis of Fatty Acid Derivates, ed. G. Knothe and
J. T. P. Derksen, AOCS Press, Champaign, Illinois, 1999,
pp. 157–181.
−
1
oxirane number = 4.36 mmol g , 1.50 g, 6.54 mmol) were con-
verted with CO . After filtration (SiO , cHex/EtOAc = 1 : 1) the
2
2
carbonated product (1.75 g) was isolated as a mixture of car- 12 M. J. S. Küppers, D. H. Müller, F. Pontzen, D. Herzog,
1
bonate 7e (84%) and 6e (16%) as a yellow oil. 7e: H NMR
300 MHz, CDCl , 22 °C): δ = 0.83–0.90 (m, 3H), 1.24–1.66 (m,
5H), 2.27–2.32 (m, 2H), 3.65 (s, 3H); 4.20–4.94 (m, 3H);
M. A. Liauw and L. Greiner, in Friction, Wear and Wear Pro-
tection, Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim,
2009, DOI: 10.1002/9783527628513.ch64.
(
3
2
1
3
1
C{ H} NMR (75 MHz, CDCl , 22 °C) δ = 13.82 (CH ), 14.02 13 M. Poliakoff, W. Leitner and E. S. Streng, Faraday Discuss.,
3
3
(CH
3
), 14.06 (CH
3
), 22.31–34.05 (multiple signals, CH
2
), 51.37
2015, 183, 9–17.
(CH), 51.42 (CH), 57.14 (CH), 57.19 (CH), 75.22–81.98 (multiple 14 G. Rokicki, P. G. Parzuchowski and M. Mazurek, Polym.
signals, CH), 153.67 (CvO), 154.73 (CvO), 174.15 (CvO),
Adv. Technol., 2015, 26, 707–761.
1
74.30 (CvO); ATR IR: νmax = 2924 (m), 2854 (m), 1798 (vs, 15 H. Blattmann, M. Fleischer, M. Bähr and R. Mülhaupt,
−1
CvO), 1736 (s), 1170 (m), 1047 (m), 773 (m) cm
.
Macromol. Rapid Commun., 2014, 35, 1238–1254.
6 M. Bähr and R. Mülhaupt, Green Chem., 2012, 14, 483–489.
7 A. Boyer, E. Cloutet, T. Tassaing, B. Gadenne, C. Alfos and
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1
1
Acknowledgements
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8 Z. Li, Y. Zhao, S. Yan, X. Wang, M. Kang, J. Wang and
H. Xiang, Catal. Lett., 2008, 123, 246–251.
9 B. Tamami, S. Sohn and G. L. Wilkes, J. Appl. Polym. Sci.,
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stoffliche Nutzung von CO : Technologien für Nachhaltigkeit
2
0 B. Schäffner, M. Blug, D. Kruse, M. Polyakov, A. Köckritz,
A. Martin, P. Rajagopalan, U. Bentrup, A. Brückner,
S. Jung, D. Agar, B. Rüngeler, A. Pfennig, K. Müller, W. Arlt,
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for the support and advice. The support of M. Jurrat and
J. Janke is gratefully acknowledged. Epoxidized vegetable oils
were provided by HOBUM Oleochemicals and are gratefully
acknowledged.
1133–1139.
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