Selectively synthesis of cyclic di- and trithiocarbonates by N-heterocyclic carbene/LiCl(Br) catalyzed addition of carbon disulfide to epoxides

Article abstract of DOI:10.1016/j.tet.2017.08.009

Carbon disulfide is an abundant, inexpensive and readily available material. One of the main challenges in the reaction of epoxides with CS₂ is to control the chemoselectivity as a variety of compounds would be formed in the reaction. A simple and convenient method toward selectively synthesis of oxathiolane and trithiocarbonate from epoxides with CS₂ catalyzed by NHC/LiCl(Br) under the neat conditions has been developed. This catalytic system exhibits excellent activity and selectivity in cycloaddition reactions of carbon disulfide to terminal epoxides.

Full text of DOI:10.1016/j.tet.2017.08.009

Accepted Manuscript
Selectively synthesis of cyclic di- and trithiocarbonates by N-heterocyclic carbene/
LiCl(Br) catalyzed addition of carbon disulfide to epoxides
Congmin Mei, Xu Li, Lihuai Liu, Changsheng Cao, Guangsheng Pang, Yanhui Shi
PII:
S0040-4020(17)30829-3
10.1016/j.tet.2017.08.009
TET 28903
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 17 May 2017
Revised Date: 4 August 2017
Accepted Date: 8 August 2017
Please cite this article as: Mei C, Li X, Liu L, Cao C, Pang G, Shi Y, Selectively synthesis of cyclic
di- and trithiocarbonates by N-heterocyclic carbene/LiCl(Br) catalyzed addition of carbon disulfide to
epoxides, Tetrahedron (2017), doi: 10.1016/j.tet.2017.08.009.
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to
our customers we are providing this early version of the manuscript. The manuscript will undergo
copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please
note that during the production process errors may be discovered which could affect the content, and all
legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT
Selectively synthesis of cyclic di- and trithiocarbonates by N-heterocyclic
carbene/LiCl(Br) catalyzed addition of carbon disulfide to epoxides
Congmin Mei, Xu Li, Lihuai Liu, Changsheng Cao, Guangsheng Pang and Yanhui Shi

ACCEPTED MANUSCRIPT
Selectively synthesis of cyclic di- and trithiocarbonates by
N-heterocyclic carbene/LiCl(Br) catalyzed addition of carbon disulfide to
epoxides
Congmin Meia, Xu Lia, Lihuai Liua, Changsheng Caoa,*, Guangsheng Pangb and Yanhui Shia,*
a
School of Chemistry and Material Science and Jiangsu Key Laboratory of Green Synthetic
Chemistry for Functional Materials, Jiangsu Normal University, Xuzhou, Jiangsu 221116, PR
China
b
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of
Chemistry, Jilin University, Changchun, Jilin 130012, PR China
Fax: (86)56183500349
Tel: +86-516-8350-0349; fax: +86-516-8350-0349; E-mail: yhshi@jsnu.edu.cn
Abstract:
Carbon disulfide is an abundant, inexpensive and readily available material. One of the main
challenges in the reaction of epoxides with CS2 is to control the chemoselectivity as a variety
of compounds would be formed in the reaction. A simple and convenient method toward
selectively synthesis of oxathiolane and trithiocarbonate from epoxides with CS2 catalyzed by
NHC/LiCl(Br) under the neat conditions has been developed. This catalytic system exhibits
excellent activity and selectivity in cycloaddition reactions of carbon disulfide to terminal
epoxides.
Keywords: Carbon disulfide; Trithiocarbonate; Dithiocarbonate; Epoxide
1. Introduction
The reaction between oxiranes and heterocumulenes, such as carbon dioxide,1 carbon
disulfide,2 isocyanates,3 isothiocyanates,4 and cardodimides5 is a straight forward
approach, leading to a wide range of corresponding five-membered ring heterocycles,
including cyclic carbonates, dithiocarbonate, trithiocarbonate
,
oxazolidinone,
2-oxathiolanimines and 2-oxazolidinimines. Among these reactions, cycloaddition of
epoxide with carbon dioxide is by far the most important and widely studied, and a
significant progress has been made in this transformation.6 Compared to carbon
1

ACCEPTED MANUSCRIPT
dioxide, the research on the cycloaddition of epoxides with its isoelectronic
heterocumulene carbon disulfide (CS2), an abundant, inexpensive and readily available
material, is very limited. One of the main challenges in this transformation is to control
the chemoselectivity. This reaction is more complex and a variety of products7, eg.
1,3-oxathiolane-2-thione7a-h
,
1,3-dithiolane-2-thione7a-h
,
thiirane7d,7f,7h
,
1,3-dithiolan-2-one7a,7b,7h, 1,3-dioxolane-2-thione7i and 1,3-oxathiolan-2-one7a,7b,7g are
frequently observed. In addition, controlling regioselectivity is another challenge.
Among these products, cyclic thiocarbonates have been widely used as intermediates
in organic and polymeric synthesis8 and also exhibit many interesting biological
activities9. Thus, a new catalytic system for selective and efficient synthesis of cyclic
thiocarbonates by the reaction of carbon disulfide with epoxides is particularly urgent
need.
Previously, we have demonstrated that the NHC/Lewis acid system is a highly active catalyst
for the activation of CO2 to synthesize cyclic carbonates, amino-functionalized ethylene
carbonates and quinazoline-2,4-diones, in which NHC is generated in-situ from deprotonation
of N,N’-disubstituted imidazolium salt-based ionic liquids (ILs) by a base.10 Thus we
anticipated that the similar systems might catalyze the reaction of epoxides with CS2. Herein,
we present the selective synthesis of cyclic dithiocarbonates and trithiocarbonates from the
cycloaddition of CS2 to epoxides catalyzed by readily available LiCl/NaHCO3/[Bmim]Br and
LiBr/ KOH/[Bmim]Br.
2. Results and discussion
2.1. Selective synthesis of cyclic dithiocarbonates
Firstly, we focused on the synthesis of 1,3-oxathiolane-2-thione. The imidazolium-based ILs,
1-butyl-3-methyl-1H-imidazol-3-ium bromide ([Bmim]Br), the base K2CO3 and the Lewis
acid ZnBr2 were selected and explored in the reaction of epoxide with CS2, as this catalytic
system showed good activity in the cycloaddition of epoxide with CO2 to prepare cyclic
carbonate10b. The reaction of 2-butyloxirane with CS2 was selected as model reaction. The
reaction was initially carried out under solvent free-conditions in the presence of ([Bmim]Br)
(10 mol%), K2CO3 (5 mol%) and ZnBr2 (5 mol%) as additive at 40 °C for 24 h (Table 1, entry
1). The result showed this catalytic system had good selectivity of 1,3-oxathiolane-2-thione
2

ACCEPTED MANUSCRIPT
over 1,3-dithiolane-2-thione. None of 4-butyl-1,3-dithiolane-2-thione (1b) was detected in
GC, whereas, 46% of 5-butyl-1,3-oxathiolane-2-thione (1a) was observed. Due to the
inspiring result, more Lewis acids ZnCl2, AlCl3, FeCl3, MgCl2 and LiCl were investigated
under the same reaction conditions (Table 1, entries 2-6). The results showed that LiCl would
slightly promote the reaction, and 50% of 1a was achieved selectively. (Table 1, entry 6).
However, neither 1a nor 1b was observed with ZnCl2, AlCl3, FeCl3 and MgCl2 as cocatalyst.
Then the effect of different bases (NaHCO3, KHCO3, Na2CO3, K3PO4, Et3N, NaOH and KOH)
on the reaction was investigated as well (Table 1, entries 7-12). The best result was obtained
by using NaHCO3 as base, leading a yield of 93% with good selectivity towards 1a. However,
none of 1a and 1b was achieved when other weak bases KHCO3, Na2CO3 and K3PO4, and
organic base Et3N were employed. When NaOH or KOH was used, good to moderate yield of
1a was achieved, however, the formation of certain amount of 1b was detected as well (8%
for NaOH and 23% for KOH). Interestingly, the result of using LiOH/KCl (Table 1, entry 13)
is quite different from that of using KOH/LiCl (Table 1, entry 12). It seems that the base has
great impact on the reaction. To understand the role of Br- and Cl- anion in the reaction, the
activity of LiBr was also examined (Table 1, entry 14). The results showed that Cl- facilitate
the reaction, it might cause by the different bond dissociation energy between of Li and X
ions, however, the real reason behind it is not clear at current stage.
A few common used ILs bearing different counter ion or alkyl chain were tested for the
reaction too, such as 1-butyl-3-methyl-1H-imidazol-3-ium chloride ([Bmim]Cl),
1-butyl-3-methyl-1H-imidazol-3-ium
1-ethyl-3-methyl-1H-imidazol-3-ium
acetate
bromide
([Bmim]OAc),
and
([Emim]Br)
1-hexyl-3-methyl-1H-imidazol-3-ium bromide ([Hmim]Br) (Table 1, entries 15-18). However,
all of them showed very poor catalytic activity. Unfortunately, a small amount of water would
harm the reaction, resulting that none of the product was formed (Table 1, entry 19). The
results of a couple of control experiments (Table 1, entries 20-23) revealed that [Bmim]Br,
LiCl and [Bmim]Br/NaHCO3 would not catalyze the reaction. Although [Bmim]Br/LiCl
could catalyze the reaction, the yield (47%) was decreased dramatically without NaHCO3
(Table 1, entry 25), indicating that the existence of base remarkably enhance the catalytic
activity.
3

ACCEPTED MANUSCRIPT
Table 1. Screening of various ILs, bases and Lewis acids for the synthesis of
1,3-oxathiolane-2-thione
Entry[a]
Ionic liquid
Base
Lewis acid
Yield (%)[b]
1a
46
0
0
0
1b
0
0
0
0
0
0
0
0
0
0
0
8
23
7
0
0
0
0
0
0
0
0
0
0
1
2
3
4
5
6
7
8
8
[Bmim]Br
[Bmim]Br
[Bmim]Br
[Bmim]Br
[Bmim]Br
[Bmim]Br
[Bmim]Br
[Bmim]Br
[Bmim]Br
[Bmim]Br
[Bmim]Br
[Bmim]Br
[Bmim]Br
[Bmim]Br
[Bmim]Br
[Bmim]Cl
[Bmim]OAc
[Emim]Br
[Hmim]Br
[Bmim]Br*
[Bmim]Br
-
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
NaHCO3
KHCO3
Na2CO3
K3PO4
Et3N
NaOH
KOH
LiOH
NaHCO3
NaHCO3
NaHCO3
NaHCO3
NaHCO3
NaHCO3
-
ZnBr2
ZnCl2
AlCl3
FeCl3
MgCl2
LiCl
LiCl
LiCl
LiCl
LiCl
LiCl
LiCl
LiCl
KCl
LiBr
LiCl
LiCl
LiCl
LiCl
LiCl
-
0
50
93
0
0
0
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
0
88
60
90
78
2
0
0
0
0
0
0
0
47
-
LiCl
-
LiCl
[Bmim]Br
[Bmim]Br
NaHCO3
-
[a] Reaction conditions: the reaction was carried out in a 4 mL of vial, containing of ionic liquid (0.1 mmol), base/Lewis acid (0.05
mmol), 2-butyloxirane (1 mmol), CS2 (3 mmol), 40 °C, 24 h. [b] GC yield, using dodecane as internal standard and the average of
two runs. *Water (1 mol%) was added.
Next, the influences of reaction time, temperature as well as the amount of LiCl/NaHCO3 and
CS2 on the reaction were investigated. As shown in entries 1-9 of Table 2, the reaction was
initiated after 10 h, and the yield moderately increased with extension of the reaction time
from 15 to 24 h. No significant increase of yield was happened after 24 h. The effect of
temperature on the reaction was investigated in the temperature range of 20-60 °C (Table 2,
entries 7 and 10-13). The results showed that the yield of 5-butyl-1,3-oxathiolane-2-thione
initially increased with elevation of the reaction temperature, then decreased when the
temperature is higher than 40 °C. The effect of LiCl/NaHCO3 loading on the reaction was
investigated in the range of 1-5 mol% (Table 2, entries 7 and 14-17). The results showed that
decreasing the amount of NaHCO3/LiCl would dramatically decrease the yield of 1a,
especially from 5 mol% to 4 mol%. Further experiments (provided in supporting information)
showed that the same dosages of NaHCO3 and LiCl are not necessary. However, if the
dosages of base and Lewis acid is less than 5 mol%, the yield of the product would
dramatically decrease under the same conditions. The equivalent of CS2 used in the reaction is
4

ACCEPTED MANUSCRIPT
also very important, 3 eq. of CS2 gave the highest yield of 1a (Table 1, entries 7 and 18-20).
Furthermore, no 1a was observed when the amount of [Bmim]Br decreased to the half
amount of 5 mol% (Table 1, entry 21).
Table 2 Screening of the amount of CS2, LiCl/NaHCO3, and [Bmim]Br, reaction time and
temperature for the synthesis of 1,3-oxathiolane-2-thione
entry[a]
CS2
(eq)
3
3
3
3
3
3
3
3
3
3
3
3
3
3
3
Loading of
LiCl/NaHCO3 (mol%)
Loading of
[Bmim]Br (mol%)
Temp
(oC)
40
40
40
40
40
40
40
40
40
20
30
50
60
40
40
40
40
40
40
40
40
Time
(h)
2
Yield (%)[b]
1a
0
1b
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
5
5
5
5
5
5
5
5
5
5
5
5
5
1
2
3
4
5
5
5
5
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
10
5
5
0
0
10
15
18
20
22
24
26
24
24
24
24
24
24
24
24
24
24
24
24
26
35
47
65
93
94
0
56
79
41
26
29
37
55
0
3
3
1
2
4
3
20
62
0
[a] Reaction conditions: the reaction was carried out in a 4 mL of vial, containing of [Bmim]Br (0.1-0.05 mmol), NaHCO3/LiCl
(0.01-0.05 mmol), 2-butyloxirane (1 mmol), CS2 (1-4 mmol), 20-60 °C, 2-26 h. [b] GC yield, using dodecane as internal standard
and the average of two runs.
To further assess the generality and scope of the reaction, a variety of epoxides were
chosen and examined in the synthesis of 1,3-oxathiolane-2-thione (Table 3). All
reactions were carried out with 10 mol% of [Bmim]Br and 5 mol% of LiCl/NaHCO3 at
40 °C for 24 h. The reactions of monosubstituted epoxides went smoothly, giving the
desired product in excellent selectivity and a yield of up to 97%. In additions, the
reaction of steric hindered disubstituted epoxides also went well with isolated yields of
up to 95% (Table 3, entry 5). In all the reactions, the other regioisomer of
1,3-oxathiolane-2-thione was not observed, however, less than 5 % of
1,3-dithiolane-2-thione was formed in the less hindered epoxides. Unfortunately,
internal epoxide does not active for this reaction. The functional groups, such as
bromide, chloride, alkene, ester, ether and furan were noticed.
5

ACCEPTED MANUSCRIPT
Table 3. Synthesis of 1,3-oxathiolane-2-thione.
R
R
O
S
5 mol% LiCl/NaHCO3
10 mol% [Bmim]Br, 40 °C, 24 h
O +
CS2
S
Entry
1
Product
Yield (%)
94
n-Bu
O
1a
S
S
S
S
S
S
S
S
S
O
2
3
2a
3a
96
97
S
O
Cl
Br
S
O
4a
5a
6a
7a
4
5
95
96
97
95
S
O
S
O
O
O
O
6
7
S
O
O
S
O
8
9
8a
9a
90
92
S
O
S
O
S
O
10
11
10a
11a
95
93
O
O
O
S
S
S
O
O
S
12
13
12a
13a
97
90
O
O
S
S
O
S
O
O
S
Reaction conditions: the reaction was carried out in a 4 mL of vial, containing of [Bmim]Br (43.8 mg, 0.2 mmol), NaHCO3 (8.4 mg,
0.1 mmol), LiCl (4.2 mg, 0.1 mmol), epoxide (2 mmol), CS2 (364 ꢀL, 6 mmol), 40 °C, 24 h. Isolated yield.
2.2. Synthesis of cyclic trithiocarbonates
Finally, we turned our attention to the synthesis of trithiocarbonate. From previous
result (Table 1, entry 12 and Table 4, entry 1), 23% of 4-butyl-1,3-dithiolane-2-thione
(
1b) was formed when LiCl/KOH was used. If we changed the LiCl to LiBr, the yield
of 1b increased to 27%, meanwhile, the yield of 1a decreased (Table 4, entry 2).
Increasing the amount of [Bmim]Br would slightly facilitate the formation of 1b
,
whereas, increasing the amount of LiCl/KOH would be largely in favor of the
formation of 1b to 78% (Table 4, entries 3-8). However, the formation of
6

ACCEPTED MANUSCRIPT
dithiocarbonate 1a was still observed in the above conditions, and this can be solved
by elevating the reaction temperature to 70 °C (Table 4, entry 9). The excellent yield of
trithiocarbonate 1b could be achieved by using a large excess of CS2 (Table 4, entries
10-12).
Table 4 Screening of conditions for the synthesis of 1,3-dithiolane-2-thione
S
S
LiBr(or LiCl)/KOH
O
CS2
O
+
S
S
S
+
[Bmim]Br, Temp., 24 h
n-Bu
n-Bu
n-Bu
1a
1b
Entry[a]
CS2
(eq.)
3
3
3
3
3
3
3
3
3
4
5
6
Ionic liquid
(mol%)
Base
(mol%)
Lewis acid
(mol%)
LiCl (5)
LiBr (5)
LiBr (5)
Temperature
(oC)
Yield (%)[b]
1a
60
1b
23
27
29
30
32
34
44
78
82
98
96
94
1
2
3
4
5
6
7
8
9
[Bmim]Br (10)
[Bmim]Br (10)
[Bmim]Br (30)
[Bmim]Br (50)
[Bmim]Br (50)
[Bmim]Br (50)
[Bmim]Br (50)
[Bmim]Br (50)
[Bmim]Br (50)
[Bmim]Br (50)
[Bmim]Br (50)
[Bmim]Br (50)
KOH (5)
KOH (5)
KOH (5)
KOH (5)
KOH (10)
KOH (30)
KOH (50)
KOH (70)
KOH (70)
KOH (70)
KOH (70)
KOH (70)
40
40
40
40
40
40
40
40
70
70
70
70
55
52
50
43
35
27
13
0
LiBr (5)
LiBr (10)
LiBr (30)
LiBr (50)
LiBr (70)
LiBr (70)
LiBr (70)
LiBr (70)
LiBr (70)
10
11
12
0
0
0
[a] Reaction conditions: the reaction was carried out in a 4 mL of vial, containing of CS2 (3-6 mmol), 2-butyloxirane (1 mmol, 121
µL), [Bmim]Br (0.1-0.5 mmol) and LiBr (or LiCl) /KOH (0.05-0.7 mmol), 40-70 °C, 24 h. [b] GC yield, using dodecane as internal
standard and the average of two runs.
The effect of reaction time on the reaction was investigated as well (Fig. 1). With
extending of the reaction time, the yield of 1b was increased and the yield of 1a was
decreased gradually. When the time reached to 24 h, no 1a was observed.
100
80
60
40
20
0
100
80
60
40
20
0
(1a)
(1b)
0
5
10
Time (h)
15
20
25
Figure 1 The effect of reaction time on the yield of 1a and 1b.
Reaction conditions: CS2 (6 mmol), 2-butyloxirane (1 mmol), [Bmim]Br (0.5 mmol) and LiBr/KOH (0.7 mmol), 70 °C, 14-24 h.
Furthermore, a variety of epoxides were chosen and examined in the synthesis of
1,3-dithiolane-2-thione (Table 5). All reactions were carried out with 50 mol% of
[Bmim]Br and 70 mol% of LiBr/KOH at 70 °C for 24 h. The conversion of both of
7

ACCEPTED MANUSCRIPT
aryl and alkyl substituted mono-substituted epoxides went smoothly, giving the desired
product in excellent selectivity and a yield of up to 97%. In additions, the conversion
of steric hindered di-substituted terminal epoxide also gave 3b in a good yield of 97%
(Table 5, entry 3).
Table 5. Synthesis of 1,3-dithiolane-2-thione.
R
R
S
S
70 mol% LiBr/KOH
50 mol% [Bmim]Br, 70 °C, 24 h
+
CS2
S
O
Entry
1
Product
Yield (%)
96
n-Bu
S
1b
2b
S
S
S
S
S
S
S
S
2
89
S
S
3
4
5
3b
4b
5b
97
90
94
S
S
O
O
O
S
S
O
S
S
6
7
6b
7b
89
87
S
S
S
O
S
O
8
9
8b
9b
88
90
S
O
O
S
S
S
S
O
S
10
11
10b
11b
92
96
S
O
S
S
S
S
Ph
S
S
12
13
12b
13b
91
95
S
S
S
S
S
O
N
O
Reaction conditions: the reaction was carried out in a 4 mL of vial, containing of [Bmim]Br (109.5 mg, 0.5 mmol), KOH (39.3 mg,
0.7 mmol), LiBr (60.8 mg, 0.7 mmol), epoxide (1 mmol), CS2 (364 ꢀL, 6 mmol), 70 °C, 24 h. Isolated yield.
As the catalyst could be separated easily from the reaction mixture, the recyclability of
the catalytic system LiBr/[Bmim]Br/KOH was examined in the reaction of 2-butyloxirane
with CS2 under optimal conditions. The yield of 1b was checked in recycle 1 to recycle 5,
8

ACCEPTED MANUSCRIPT
and the results were shown in Fig. 2. The results indicated that the catalyst could be
used for 3 times without loss of the catalytic activity, however, the yield of 1b
decreased gradually after 3 times. It is probably due to less and less amount of catalyst
recovered during the recycle process.
100
80
60
40
20
0
100
80
60
40
20
0
1
2
3
4
5
Number of Run
Figure 2 Recycling of the catalytic system LiBr/[Bmim]Br/KOH.
Reaction conditions: CS2 (6 mmol), 2-butyloxirane (1 mmol), [Bmim]Br (0.5 mmol) and LiBr/KOH (0.7 mmol), 70 °C, 24 h.
To understand the reaction mechanism, the corresponding NHC-CS2 adduct,
1-n-butyl-3-methylimidazolium-2-carbondithioate were prepared and a few control reactions
were carried out as shown in Scheme 1. In the reaction 1 catalyzed by NHC-CS2,
2-butyloxirane
reacted
with
CS2
smoothly
giving
cycloaddition
product,
1,3-oxathiolane-2-thione 1a in 40%, whereas, the yield of 1a increased to 92% with LiCl as
an additive (reaction 2). These indicated that NHC-CS2 would catalyse the reaction, and the
adding LiCl would facilitate the reaction. As a trace amount of 2-butylthiirane was detected
by GC-MS occasionally, it suggested that 2-alkylthiirane was generated and it might be the
intermediate for the formation of 1,3-dithiolane-2-thione. The commercial available
2-ethylthiirane was tested in the reaction with CS2 catalyzed by NHC-CS2 (reaction 3 and 4).
The result showed that NHC-CS2 would catalyze the reaction to give 1,3-dithiolane-2-thione
as product, and the adding LiBr would facilitate the reaction. Additionally, the reaction 5
indicated that compound 1b could be achieved from 1a directly, suggesting
1,3-dithiolane-2-thione is generated from 1,3-oxathiolane-2-thion via thiirane.
9

ACCEPTED MANUSCRIPT
S
10 mol% NHC-CS2
O
O
S
+
O
S
3 CS2
3 CS2
6 CS2
6 CS2
6 CS2
(1)
(2)
40 °C, 24 h
Yield: 40%
n-Bu
n-Bu
Et
n-Bu
1a
5 mol% LiCl
10 mol% NHC-CS2
S
+
+
+
O
S
40 °C, 24 h
Yield: 92%
n-Bu
1a
S
50 mol% NHC-CS2
S
S
S
(3)
(4)
(5)
70 °C, 24 h
Yield: 55%
Et
70 mol% LiBr
50 mol% NHC-CS2
S
S
S
S
70 °C, 24 h
Yield: 90%
Et
Et
70 mol% LiBr/KOH
50 mol% [Bmim]Br
S
S
S
O
+
S
70 °C, 24 h
Yield: 97%
n-Bu
n-Bu
1a
1b
Scheme 1 The control reactions
Based on these results, we propose the following mechanism for these reactions
(Scheme 2). NHC is generated through the reaction of [Bmim]Br with base to give
NHC-CS2 adduct, meanwhile, ring-opening of the epoxide by halide anion generates
the alkyl halide. Then the nucleophilic substitution reaction of NHC-CS2 to the alkyl
halide gives an intermediate
i, which could cyclize to result in the formation of
1,3-oxathiolane-2-thione and regenerate the catalysts. The ring open intermediate ii
a
of 1,3-oxathiolane-2-thione by nucleophile (might be OH-) would lead the formation of
alkylthiirane, which would further react with NHC-CS2, generating
1,3-dithiolane-2-thione b.
10

ACCEPTED MANUSCRIPT
S
N
S
N
n-Bu
S
S
S
S
R
b
R
N
S
N
S
n-Bu
CS2
Li
O
LiX
O
S
X
R
R
R
Nu
S
O
LiX
N
N
n-Bu
N
N
n-Bu
Nu
S
base
S
S
O
R
S
O
i
R
ii
N
N
n-Bu
Br
S
Nu
S
O
R
a
Scheme 2 The proposed reaction mechanism
3. Conclusion
In summary, an efficient catalyst system for selective cycloaddition of CS2 to epoxides
was developed using inexpensive and readily available compounds. Under neat
conditions, the reaction of diverse terminal epoxides with CS2 catalysed by the catalyst
system
LiCl/[Bmim]Br/NaHCO3
would
selectively
lead
cyclic
1,3-oxathiolane-2-thione up to 97% yield, meanwhile, the catalyst system
LiBr/[Bmim]Br/KOH would selectively lead 1,3-dithiolane-2-thione up to 97% yield.
4. Experimental section
4.1. General information
All substrates and reagents are commercially available and were used as received. 1H and 13C
NMR spectra were recorded on Bruker AV400 spectrometer at 25 °C. Chemical shift values
are expressed in ppm relative to solvent residue. GC-MS was performed on an Agilent
6890-5973N system with electron ionization (EI) mass spectrometry. IR spectra were
recorded on KBr pellets on a FTIR-Tensor 27 spectrometer. HRMS was recorded on a Fisher
LTQ-Orbitrap XL combined-type mass spectrometry.
4.2. Preparation of 1-n-butyl-3-methylimidazolium-2-carbondithioate
11

ACCEPTED MANUSCRIPT
To 15 mL of THF in an oven-dried round-bottom flask equipped with a magnetic stir bar was
added 1-n-butyl-3-methylimidazolium bromide (0.110 g, 0.5 mmol) and K2CO3 (0.067 g, 0.6
mmol) under nitrogen atmosphere. CS2 (300 ꢀL, 5 mmol) was injected into the reaction
mixture by a syringe and the resulting suspension was stirred at 80 °C for 24 h. The solvent
was removed by rotary evaporation and the residue was purified by column to give the
product as red oil. Yield: 80%.1H NMR (400 MHz, CDCl3): δ 6.85 (d, J = 8.0 Hz, 2H, 2 ×
NCH), 4.13 (t, J = 7.6 Hz, 2H, 1-Bu-CH2), 3.79 (s, 3H, CH3), 1.91–1.84 (m, 2H, 2-Bu-CH2),
13
1.42–1.36 (dd, J = 15.2, 7.6 Hz, 2H, 3-Bu-CH2), 0.94 (t, J = 7.2 Hz, 3H, 4-Bu-CH3). C
NMR (100 MHz, CDCl3): δ 224.7 (C=S), 128.9 (2-C), 118.3 (4-C), 117.7 (5-C), 48.5
(1-Bu-CH2), 35.0 (CH3), 31.8 (2-Bu-CH2), 19.8 (3-Bu-CH2), 13.6 (4-Bu-CH3). FI-IR (KBr):
3074, 2957, 1659, 1455, 1196 (C=S), 834, 756, 627 cm-1. HRMS (ESI) m/z: Calcd. for
C9H14N2S2Na [M+Na]+: 237.0496, found: 237.0507.
4.3. General procedure for the synthesis of dithiocarbonates
To a 4 mL of vial was charged with [Bmim]Br (43.8 mg, 0.2 mmol), NaHCO3 (8.4 mg, 0.1
mmol), LiCl (4.2 mg, 0.1 mmol), epoxide (2 mmol) and CS2 (364 ꢀL, 6 mmol). The reaction
mixture was stirred at 40 °C for 24 h, after which time, water (5 mL) was added into the
reaction mixture. The organic layer was extracted with CH2Cl2 (3 × 5 mL). The combined
organic phase was dried over anhydrous Na2SO4 and concentrated under reduced pressure.
The residue was purified by flash column chromatography on silica gel (petroleum ether/ethyl
acetate = 4:1 as eluent).
4.4. General procedure for the synthesis of trithiocarbonates
To a 4 mL of vial was charged with [Bmim]Br (109.5 mg, 0.5 mmol), KOH (39.3 mg, 0.7
mmol), LiBr (60.8 mg, 0.7 mmol), epoxide (1 mmol) and CS2 (364 ꢀL, 6 mmol) under air.
The reaction mixture was stirred at 70 °C for 24 h, after which time, water (5 mL) was added
into the reaction mixture. The organic layer was extracted with CH2Cl2 (3 × 5 mL). The
combined organic phase was dried over anhydrous Na2SO4 and concentrated under reduced
pressure. The residue was purified by flash column chromatography on silica gel (petroleum
ether/ethyl acetate = 4:1 as eluent).
4.5. Recycling procedure of the catalytic system LiBr/[Bmim]Br/KOH
To a 4 mL of vial was charged with [Bmim]Br (109.5 mg, 0.5 mmol), KOH (39.3 mg, 0.7
12

ACCEPTED MANUSCRIPT
mmol), LiBr (60.7 mg, 0.7 mmol), 2-butyloxirane (121 ꢀL, 1 mmol) and CS2 (364 ꢀL, 6
mmol). The reaction mixture was stirred at 70 °C for 24 h, after which time, the organic phase
was separated from the reaction mixture through extraction with ethyl acetate (4 × 2 mL). The
residue was dried under vacuum to remove left ethyl acetate giving the recovered catalyst. To
the recovered catalyst, 2-butyloxirane (121 ꢀL, 1 mmol) and CS2 (364 ꢀL, 6 mmol) were
added, and then a second run of 24 h at 40 °C was performed. This operation was
continuously repeated.
4.6. Data for dithiocarbonates (1a-13a)
4.6.1. 5-n-butyl-1,3-oxathiolane-2-thione(1a)2
1
Yellow oil. H NMR (400 MHz, CDCl3): δ 5.09–5.05 (m, 1H, OCH), 3.57 (dd, J = 11.2, 6.8
Hz, 1H, SCH2), 3.37 (t, J = 10.4 Hz, 1H, SCH2), 1.96 (s, 1H, 1-Bu-CH2), 1.83–1.76 (m, 1H,
1-Bu-CH2), 1.55–1.44 (m, 1H, 2-Bu-CH2), 1.38–1.34 (m, 3H, 2-Bu-CH2, 3-Bu-CH2), 0.90 (t,
13
J = 7.2 Hz, 3H, 4-Bu-CH3). C NMR (100 MHz, CDCl3): δ 212.4 (C=S), 92.0 (5-C), 39.3
(4-C), 33.3 (1-Bu-CH2), 27.4 (2-Bu-CH2), 22.3 (3-Bu-CH2), 13.8 (CH3). FI-IR (KBr): 2957,
2862, 1458, 1350, 1231, 1191 (C=S), 1101, 1047, 956 cm-1.
4.6.2. 5-ethyl-1,3-oxathiolane-2-thione (2a)2
1
Yellow oil. H NMR (400 MHz, CDCl3): δ 5.09–5.03 (m, 1H, OCH), 3.58 (dd, J = 10.8, 6.4
Hz, 1H, SCH2), 3.40 (dd, J = 10.8, 9.6 Hz, 1H, SCH2), 2.07–2.00 (m, 1H, 1-Et-CH2),
1.91–1.84 (m, 1H, 1-Et-CH2), 1.09 (t, J = 7.6 Hz, 3H, 2-Et-CH3). 13C NMR (100 MHz,
CDCl3): δ 212.5 (C=S), 93.1 (5-C), 38.9 (4-C), 26.8 (1-Et-CH2), 9.7 (2-Et-CH3). FI-IR (KBr):
3102, 2946, 2360, 2342, 1169 (C=S), 1109, 1066, 669 cm-1.
4.6.3. 5-(chloromethyl)-1,3-oxathiolane-2-thione (3a)2
1
Yellow oil. H NMR (400 MHz, CDCl3): δ 5.36–5.29 (m, 1H, OCH), 3.90–3.81 (m, 2H,
SCH2), 3.77–3.69 (m, 2H, CH2-Cl). 13C NMR (100 MHz, CDCl3): δ 211.0 (C=S), 88.4 (5-C),
43.0 (4-C), 36.7 (CH2-Cl). FI-IR (KBr): 2930, 2832, 2361, 1734, 1508, 1232, 1185 (C=S),
1049, 932, 824, 744, 652 cm-1.
4.6.4. 5-(bromomethyl)-1,3-oxathiolane-2-thione (4a)11
1
Yellow oil. H NMR (400 MHz, CDCl3): δ 5.36–5.29 (m, 1H, OCH), 3.77 (dd, J = 11.2, 7.2
13
Hz, 1H, SCH2), 3.70–3.65 (m, 3H, SCH2, CH2-Br). C NMR (100 MHz, CDCl3): δ 210.5
(C=S), 88.1 (5-C), 38.1 (4-C), 30.0 (CH2-Br). FI-IR (KBr): 3015, 2283, 1732, 1437, 1337,
13

ACCEPTED MANUSCRIPT
1226, 1184 (C=S), 1050, 995, 870, 639 cm-1.
4.6.5. 5,5-dimethyl-1,3-oxathiolane-2-thione (5a)2
1
13
Yellow oil. H NMR (400 MHz, CDCl3): δ 3.44 (s, 2H, SCH2), 1.65 (s, 6H, 2 × CH3). C
NMR (100 MHz, CDCl3): δ 211.3 (C=S), 97.2 (5-C), 45.5 (4-C), 26.2 (CH3). FI-IR (KBr):
2960, 2227, 1725, 1507, 1291, 1190 (C=S), 1071, 1045, 756 cm-1.
4.6.6. 5-((allyloxy)methyl)-1,3-oxathiolane-2-thione (6a)11
1
Yellow oil. H NMR (400 MHz, CDCl3): δ 5.85–5.76 (m, 1H, vinyl-H), 5.26–5.13 (m, 3H,
vinyl-H, OCH), 4.01–3.99 (m, 2H, vinyl-CH2), 3.78–3.65 (m, 2H, OCH2), 3.63–3.55 (m, 2H,
13
SCH2). C NMR (100 MHz, CDCl3): δ 212.0 (C=S), 133.6 (vinyl-C), 117.6 (vinyl-C), 89.3
(5-C), 72.2 (OCH2), 68.4 (vinyl-CH2), 35.8 (4-C). FI-IR (KBr): 3123, 2989, 2361, 2343, 1192
(C=S), 1066, 670 cm-1.
4.6.7. 5-((furan-2-ylmethoxy)methyl)-1,3-oxathiolane-2-thione (7a)
1
Yellow oil. H NMR (400 MHz, CDCl3): δ 7.40–7.39 (m, 1H, furan-H), 6.35–6.32 (m, 2H,
furan-H), 5.21–5.15 (m, 1H, OCH), 4.51 (d, J = 2.8 Hz, 2H, furan-CH2), 3.80 (dd, J = 11.2,
13
6.8 Hz, 1H, OCH2), 3.74(dd, J = 10.8, 4.4 Hz, 1H, OCH2), 3.63–3.52 (m, 2H, SCH2). C
NMR (100 MHz, CDCl3): δ 212.0 (C=S), 150.6 (furan-C), 143.0 (furan-C), 110.3 (furan-C),
110.1 (furan-C), 89.1 (5-C), 68.1 (furan-CH2), 65.1 (OCH2), 35.9 (4-C). FI-IR (KBr): 3118,
2907, 1732, 2360, 1355, 1231, 1191 (C=S), 1093, 1049, 919, 749, 600 cm-1. HRMS (ESI) m/z:
Calcd. for C9H10O3S2Na [M+Na] +: 252.9969, found: 252.9966.
4.6.8. 5-((benzyloxy)methyl)-1,3-oxathiolane-2-thione (8a)7h
1
Yellow oil. H NMR (400 MHz, CDCl3): δ 7.39–7.30 (m, 5H, Ph-H), 5.26–5.20 (m, 1H,
OCH), 4.64–4.56 (m, 2H, Ph-CH2), 3.83 (dd, J = 10.8, 4.8 Hz, 1H, OCH2), 3.75 (dd, J = 10.8,
13
4.8 Hz, 1H, OCH2), 3.68–3.55 (m, 2H, SCH2). C NMR (100 MHz, CDCl3): δ 213.0 (C=S),
137.2 (Ph-C), 128.6 (Ph-C), 128.1 (Ph-C), 127.9 (Ph-C), 89.2 (5-C), 73.8 (OCH2), 68.6
(Ph-CH2), 36.2 (4-C). FI-IR (KBr): 2864, 2361, 1734, 1453, 1230, 1192 (C=S), 1101, 1049,
740, 699 cm-1.
4.6.9. 5-((o-tolyloxy)methyl)-1,3-oxathiolane-2-thione (9a)7h
Yellow oil. 1H NMR (400 MHz, CDCl3): δ 7.17 (d, J = 7.2 Hz, 2H, Ph-H), 6.93 (t, J = 6.8 Hz,
1H, Ph-H), 6.80 (d, J = 8.0 Hz , 1H, Ph-H), 5.51–5.45 (m, 1H, OCH), 4.33 (dd, J = 10.4, 4.8
Hz, 1H, OCH2), 4.25 (dd, J = 10.4, 6.4 Hz, 1H, OCH2), 3.83–3.75 (m, 2H, SCH2), 2.25 (s, 3H,
14

ACCEPTED MANUSCRIPT
CH3). 13C NMR (100 MHz, CDCl3): δ 211.7 (C=S), 155.9 (Ph-C), 131.0 (Ph-C), 127.0 (Ph-C),
127.0 (Ph-C) 121.6 (Ph-C), 111.1 (Ph-C), 88.1 (5-C), 66.8 (OCH2), 36.2 (4-C), 16.2 (CH3).
FI-IR (KBr): 2924, 2867, 2361, 1734, 1602, 1495, 1458, 1246, 1186 (C=S), 1121, 1050, 932,
831, 752 cm-1.
4.6.10. 5-((4-methoxyphenoxy)methyl)-1,3-oxathiolane-2-thione (10a)
1
Yellow oil. H NMR (400 MHz, CDCl3): δ 6.87–6.81 (m, 4H, Ph-H), 5.43–5.36 (m, 1H,
OCH), 4.28–4.07 (m, 2H, SCH2), 3.75 (s, 3H, OCH3), 2.03 (s, 1H, OCH2), 1.25 (t, J = 6.8 Hz,
13
1H, OCH2). C NMR (100 MHz, CDCl3): δ 211.6 (C=S), 154.6 (Ph-C), 151.9 (Ph-C), 115.8
(Ph-C), 114.8 (Ph-C), 88.1 (5-C), 67.3 (OCH2), 55.7 (OCH3), 36.2 (4-C). FI-IR (KBr): 2964,
2360, 1590, 1505, 1254, 1189 (C=S), 1125, 1055, 1035, 865, 744 cm-1. HRMS (ESI) m/z:
Calcd. for C11H12O3S2Na [M+Na] +: 279.0126, found: 279.0144.
4.6.11. 5-((2-methoxyphenoxy)methyl)-1,3-oxathiolane-2-thione (11a)
1
Yellow oil. H NMR (400 MHz, CDCl3): δ 7.04–6.99 (m, 1H, Ph-H), 6.96–6.90 (m, 3H,
Ph-H), 5.48–5.41 (m, 1H, OCH), 4.33 (d, J = 5.2 Hz, 2H, OCH2), 3.88 (d, J = 8.0 Hz, 1H,
13
SCH2), 3.85 (s, 3H, OCH3), 3.75 (dd, J = 11.2, 7.2 Hz, 1H, SCH2). C NMR (100 MHz,
CDCl3): δ 211.7 (C=S), 150.2 (Ph-C), 147.4 (Ph-C), 123.3 (Ph-C), 121.1 (Ph-C), 116.2 (Ph-C),
112.4 (Ph-C), 88.1 (5-C), 68.5 (OCH2), 55.9 (CH3), 36.5 (4-C). FI-IR (KBr): 2964, 2359,
1505, 1254, 1187 (C=S), 1125, 1056, 745 cm-1. HRMS (ESI) m/z: Calcd. for C11H12O3S2Na
[M+Na] +: 279.0126, found: 279.0142.
4.6.12. 5-(phenoxymethyl)-1,3-oxathiolane-2-thione (12a)2
Yellow oil. 1H NMR (400 MHz, CDCl3): δ 7.31 (t, J = 7.6 Hz, 2H, Ph-H), 7.01 (t, J = 7.2 Hz,
1H, Ph-H), 6.92 (d, J = 8.0 Hz, 2H, Ph-H), 5.45–5.38 (m, 1H, OCH), 4.33–4.23 (m, 2H,
OCH2), 3.79–3.68 (m, 2H, SCH2). 13C NMR (100 MHz, CDCl3): δ 211.7 (C=S), 157.6 (Ph-C),
129.6 (Ph-C), 121.7 (Ph-C), 114.5 (Ph-C), 88.1 (5-C), 66.4 (OCH2), 36.0 (4-C). FI-IR (KBr):
2933, 1718, 1599, 1497, 1292, 1244, 1192 (C=S), 1173, 1079, 1046, 813, 755, 692 cm-1.
4.6.13. (2-thioxo-1,3-oxathiolan-5-yl)methyl benzoate (13a)7h
Yellow oil. 1H NMR (400 MHz, CDCl3): δ 8.03 (d, J = 6.8 Hz, 2H, Ph-H), 7.57 (t, J = 7.6 Hz,
1H, Ph-H), 7.44 (t, J = 8.0 Hz, 2H, Ph-H), 5.47–5.43 (m, 1H, OCH), 4.69–4.59 (m, 2H,
OCH2), 3.76–3.61 (m, 2H, SCH2). 13C NMR (100 MHz, CDCl3): δ 211.2 (C=S), 165.9 (C=O),
133.6 (Ph-C), 129.8 (Ph-C), 128.9 (Ph-C), 128.6 (Ph-C), 87.7 (5-C), 63.5 (OCH2), 36.0 (4-C).
15

ACCEPTED MANUSCRIPT
FI-IR (KBr): 2956, 1720, 1599, 1449, 1283, 1187 (C=S), 1117, 1060, 1024, 871, 715 cm-1.
4.7. Data for trithiocarbonates (1b-13b)
4.7.1. 4-butyl-1,3-dithiolane-2-thione (1b)2
1
Yellow oil. H NMR (400 MHz, CDCl3): δ 4.42–4.35 (m, 1H, SCH), 3.96 (dd, J = 11.6, 5.2
Hz, 1H, SCH2), 3.71 (dd, J = 12.0, 8.0 Hz, 1H, SCH2), 1.99–1.87 (m, 2H, 1-Bu-CH2),
1.45–1.34 (m, 4H, 2-Bu-CH2, 3-Bu-CH2), 0.93 (t, J = 7.2 Hz, 3H, 4-Bu-CH3). 13C NMR (100
MHz, CDCl3): δ 228.1 (C=S), 61.1 (5-C), 48.3 (4-C), 33.3 (1-Bu-CH2), 30.5 (2-Bu-CH2), 22.5
(3-Bu-CH2), 14.0 (4-Bu-CH3). FI-IR (KBr): 2956, 2927, 2359, 1464, 1095, 1062 (C=S), 871
cm-1.
4.7.2. 4-ethyl-1,3-dithiolane-2-thione (2b)2
1
Yellow oil. H NMR (400 MHz, CDCl3): δ 4.36–4.29 (m, 1H, SCH), 3.99 (dd, J = 12.0, 5.6
Hz, 1H, SCH2), 3.71 (dd, J = 12.0, 7.6 Hz, 1H, SCH2), 2.03–1.91 (m, 2H, 1-Et-CH2), 1.08 (t,
13
J = 7.2 Hz, 3H, 2-Et-CH3). C NMR (100 MHz, CDCl3): δ 228.1 (C=S), 62.6 (5-C), 48.0
(4-C), 26.9 (1-Et-CH2), 12.7 (2-Et-CH3). FI-IR (KBr): 2961, 2927, 2358, 1456, 1421, 1086,
1051 (C=S), 873 cm-1.
4.7.3. 4,4-dimethyl-1,3-dithiolane-2-thione (3b)2
1
13
Yellow oil. H NMR (400 MHz, CDCl3): δ 3.75 (s, 2H, SCH2), 1.74 (s, 6H, 2 × CH3). C
NMR (100 MHz, CDCl3): δ 227.7 (C=S), 66.2 (5-C), 55.8 (4-C), 27.6 (CH3). FI-IR (KBr):
3447, 2962, 2923, 2342, 1683, 1457, 1398, 1091, 1059 (C=S), 874, 669 cm-1.
4.7.4. 4-((allyloxy)methyl)-1,3-dithiolane-2-thione (4b)11
1
Yellow oil. H NMR (400 MHz, CDCl3): δ 5.93–5.83 (m, 1H, vinyl-H), 5.31–5.21 (m, 2H,
vinyl-H), 4.50–4.44 (m, 1H, SCH), 4.10–4.03 (m, 3H, vinyl-CH2, OCH2), 3.95 (dd, J = 12.0 ,
4.8 Hz, 1H, OCH2), 3.82 (t, J = 9.2 Hz, 1H, SCH2), 3.66–3.62 (m, 1H, SCH2). 13C NMR (100
MHz, CDCl3): δ 227.4 (C=S), 133.9 (vinyl-C), 118.2 (vinyl-C), 72.5 (OCH2), 69.1 (vinyl
-CH2), 58.2 (5-C), 45.1 (4-C). FI-IR (KBr): 2885, 2342, 1669, 1533, 1396, 1075 (C=S), 928,
669 cm-1.
4.7.5. 4-((furan-2-ylmethoxy)methyl)-1,3-dithiolane-2-thione (5b)
Yellow oil. 1H NMR (400 MHz, CDCl3): δ 7.43 (s, 1H, furan-H), 6.36 (s, 2H, furan-H), 4.52
(s, 2H, furan-CH2), 4.43–4.37 (m, 1H, SCH), 4.06 (dd, J = 12.0, 5.6 Hz, 1H, OCH2), 3.92 (dd,
J = 12.0, 4.4 Hz, 1H, OCH2), 3.85 (t, J = 9.6 Hz, 1H, SCH2), 3.67 (dd, J = 10.0, 5.6 Hz, 1H,
16

ACCEPTED MANUSCRIPT
SCH2). 13C NMR (100 MHz, CDCl3): δ 226.7 (C=S), 154.7 (furan-C), 152.0 (furan-C), 115.9
(furan-C), 114.9 (furan-C), 67.6 (furan-CH2), 57.5 (OCH2), 55.8 (5-C), 45.0 (4-C). FI-IR
(KBr): 2939, 2356, 1598, 1496, 1461, 1239, 1072 (C=S), 1037, 876, 759, 692 cm-1. HRMS
(ESI) m/z: Calcd. for C9H10O2S3Na [M+Na] +: 268.9741, found: 268.9751.
4.7.6. 4-((benzyloxy)methyl)-1,3-dithiolane-2-thione (6b)7h
1
Yellow oil. H NMR (400 MHz, CDCl3): δ 7.40–7.32 (m, 5H, Ph-H), 4.59 (s, 2H, Ph-CH2),
4.50–4.45 (m, 1H, SCH), 4.06 (dd, J = 12.0, 5.6 Hz, 1H, OCH2), 3.95 (dd, J = 12.4, 4.8 Hz,
1H, OCH2), 3.86 (t, J = 9.2 Hz, 1H, SCH2), 3.69 (dd, J = 10.0, 6.0 Hz, 1H, SCH2). 13C NMR
(100 MHz, CDCl3): δ 227.4 (C=S), 137.3 (Ph-C), 128.7 (Ph-C), 128.2 (Ph-C), 127.9 (Ph-C),
73.6 (Ph-CH2), 69.1 (5-C), 58.3 (OCH2), 45.0 (4-C). FI-IR (KBr): 3674, 3566, 3466, 3028,
2858, 2360, 1647, 1362, 1103, 1074 (C=S), 865, 738, 698 cm-1.
4.7.7. 4-((o-tolyloxy)methyl)-1,3-dithiolane-2-thione(7b)
Yellow oil. 1H NMR (400 MHz, CDCl3): δ 7.18 (t, J = 6.4 Hz, 2H, Ph-H), 6.92 (t, J = 7.2 Hz,
1H, Ph-H), 6.82 (d, J = 8.4 Hz, 1H, Ph-H), 4.73–4.67 (m, 1H, OCH2), 4.38 (t, J = 9.2 Hz, 1H,
OCH2), 4.25–4.19 (m, 2H, SCH2), 4.09 (dd, J = 12.0, 4.0 Hz, 1H, SCH), 2.24 (s, 3H, CH3).
13C NMR (100 MHz, CDCl3): δ 226.6 (C=S), 155.9 (Ph-C), 131.2 (Ph-C), 127.1 (Ph-C),
126.9 (Ph-C), 121.7 (Ph-C), 111.3 (Ph-C), 66.9 (5-C), 57.7 (OCH2), 45.1 (4-C), 16.4 (CH3).
FI-IR (KBr):: 2917, 2869, 2359, 1495, 1290, 1244, 1062 (C=S), 897, 756 cm-1. HRMS (ESI)
m/z: Calcd. for C11H12OS3Na [M+Na] +: 278.9948, found: 278.9945.
4.7.8. 4-((4-methoxyphenoxy)methyl)-1,3-dithiolane-2-thione (8b)
1
Yellow oil. H NMR (400 MHz, CDCl3): δ 6.85 (s, 4H, Ph-H), 4.64–4.58 (m, 1H, OCH2),
4.31 (t, J = 9.6 Hz, 1H, SCH), 4.19 (dd, J = 12.4, 5.6 Hz, 1H, OCH2), 4.13 (dd, J = 10.0, 5.6
13
Hz, 1H, SCH2), 4.05 (dd, J = 12.0, 4.0 Hz, 1H, SCH2), 3.77 (s, 3H, OCH3). C NMR (100
MHz, CDCl3): δ 226.7 (C=S), 154.7 (Ph-C), 152.0 (Ph-C), 115.9 (Ph-C), 114.9 (Ph-C), 67.6
(5-C), 57.5 (OCH3), 55.8 (OCH2), 45.0 (4-C). FI-IR (KBr): 3447, 2929, 2360, 1652, 1508,
1457, 1398, 1230, 1040 (C=S), 825 cm-1. HRMS (ESI) m/z: Calcd. for C11H12O2S3Na [M+Na]
+: 294.9897, found: 294.9885.
4.7.9. 4-((2-methoxyphenoxy)methyl)-1,3-dithiolane-2-thione (9b)
1
Yellow oil. H NMR (400 MHz, CDCl3): δ 7.04–7.02 (m, 1H, Ph-H), 6.96–6.89 (m, 3H,
Ph-H), 4.69–4.63 (m, 1H, OCH2), 4.35 (t, J = 10.0 Hz, 1H, SCH), 4.26–4.16 (m, 3H, OCH2,
17

ACCEPTED MANUSCRIPT
OCH2), 3.86 (s, 3H, OCH3). 13C NMR (100 MHz, CDCl3): δ 226.9 (C=S), 150.1 (Ph-C),
147.3 (Ph-C), 123.2 (Ph-C), 121.1 (Ph-C), 115.9 (Ph-C), 112.3 (Ph-C), 68.6 (5-C), 57.4
(OCH2), 56.0 (OCH3), 45.2 (4-C). FI-IR (KBr): 2927, 2359, 1647, 1505, 1222, 1177, 1123,
1079 (C=S), 1039 cm-1. HRMS (ESI) m/z: Calcd. for C11H12O2S3Na [M+Na] +: 294.9897,
found: 294.9889.
4.7.10. 4-(phenoxymethyl)-1,3-dithiolane-2-thione (10b)11
Yellow oil. 1H NMR (400 MHz, CDCl3): δ 7.32 (t, J = 8.0 Hz, 1H, Ph-H), 7.02 (t, J = 7.2 Hz,
1H, Ph-H), 6.92 (d, J = 8.4 Hz, 2H, Ph-H), 4.67–4.61 (m, 1H, OCH2), 4.37 (t, J = 9.6 Hz, 1H,
13
SCH), 4.25–4.17 (m, 2H, OCH2, SCH2), 4.07 (dd, J = 12.0, 3.6 Hz, 1H, SCH2). C NMR
(100 MHz, CDCl3): δ 226.6 (C=S), 157.8 (Ph-C), 129.8 (Ph-C), 122.0 (Ph-C), 114.7 (Ph-C),
66.6 (5-C), 57.4 (OCH2), 45.1 (4-C). FI-IR (KBr): 3750, 3675, 3649, 2922, 2360, 1598, 1496,
1461, 1238, 1072, 1058, 1037 (C=S), 876, 759, 692 cm-1.
4.7.11. 4-phenyl-1,3-dithiolane-2-thione (11b)2
1
Yellow solid, mp: 84–86 ºC. H NMR (400 MHz, CDCl3): δ 7.51–7.49 (m, 2H, Ph-H),
7.44–7.43 (m, 3H, Ph-H), 5.64 (dd, J = 10.8, 6.0 Hz, 1H, SCH), 4.18 (t, J = 11.2 Hz, 1H,
13
SCH2), 4.04 (dd, J = 12.0, 5.6 Hz, 1H, SCH2). C NMR (100 MHz, CDCl3): δ 227.4 (C=S),
135.2 (Ph-C), 129.3 (Ph-C), 129.3 (Ph-C), 127.6 (Ph-C), 84.3 (5-C), 49.8 (4-C). FI-IR (KBr):
2360, 1487, 1450, 1419, 1230, 1175, 1054 (C=S), 882, 768, 727, 696 cm-1.
4.7.12. 4-hexyl-1,3-dithiolane-2-thione (12b)2
Yellow oil. 1H NMR (400 MHz, CDCl3): δ 4.43–4.36 (m, 1H, CH2), 3.96 (dd, J = 11.6, 5.2 Hz,
1H, SCH), 3.70 (dd, J = 12.0, 8.0 Hz, 1H, SCH2), 2.00–1.85 (m, 2H, 1-Hex-CH2), 1.44–1.25
(m, 8H, 4 × CH2), 0.89 (t, J = 6.4 Hz, 3H, CH3). 13C NMR (100 MHz, CDCl3): δ 228.1 (C=S),
61.1 (5-C), 48.3 (4-C), 33.6 (4-Hex-CH2), 31.6 (1-Hex-CH2), 29.0 (3-Hex-CH2), 28.4
(2-Hex-CH2), 22.6 (5-Hex-CH2), 14.1 (CH3). FI-IR (KBr): 2955, 2926, 2853, 2360, 1653,
1457, 1067 (C=S), 872, 669 cm-1.
4.7.13. 2-((2-thioxo-1,3-dithiolan-4-yl)methyl)isoindoline-1,3-dione (13b)
1
Yellow oil. H NMR (400 MHz, CDCl3): δ 7.91–7.87 (m, 2H, Ph-H), 7.80–7.76 (m, 2H,
Ph-H), 4.70–4.64 (m, 1H, SCH), 4.27 (dd, J = 14.4, 8.8 Hz, 1H, SCH2), 4.14–4.05 (m, 2H,
NCH2), 3.77 (dd, J = 12.4, 4.4 Hz, 1H, SCH2). 13C NMR (100 MHz, CDCl3): δ 225.8 (C=S),
168.1 (C=O), 134.7 (Ph-C), 131.7 (Ph-C), 123.9 (Ph-C), 57.3 (5-C), 46.1 (4-C), 39.4 (NCH2).
18

ACCEPTED MANUSCRIPT
FI-IR (KBr): 3710, 3628, 3100, 2360, 1716, 1575, 1349, 1099, 1076 (C=S), 908, 717, 669
cm-1. HRMS (ESI) m/z: Calcd. for C12H9NO2S3Na [M+Na] +: 317.9693, found: 317.9684.
Acknowledgements
We are grateful to National Natural Science Foundation of China (NSFC 21571087),
Major Projects of Natural Science Research in Jiangsu Province (15KJA150004),
PAPD and TAPP of Jiangsu Higher Education Institutions, and the State Key
Laboratory of Inorganic Synthesis and Preparative Chemistry at Jilin University
(2016-01) for financial support.
Notes and references
1. (a) Sakakura T, Choi JC, Yasuda H. Chem Rev. 2007; 107:2365;
(b) Omae I. Coord Chem Rev. 2012; 256:1384;
(c) North M, Pasquale R, Young C. Green Chem. 2010; 12:1514;
(d) Lu X-B, Darensbourg DJ. Chem Soc Rev. 2012; 41:1462;
(e) Pescarmona PP, Taherimehr M. Catal Sci Technol. 2012; 2:2169.
2. Clegg W, Harrington RW, North M, Villuendas P. J Org Chem. 2010; 75:6201.
3. (a) Wang P, Qin J, Yuan D, Wang Y-R, Yao Y-M. ChemCatChem. 2015; 7:1145;
(b) Paddock RL, Adhikari D, Lord RL, Baik M, Nguyen ST. Chem Commun. 2014;
50:15187;
(c) Baronsky T, Beattie C, Harrington RW, Irfan R, North M, Osende JG, Young C. ACS
Catal. 2013; 3:790;
(d) Shibata I, Baba A, Iwasaki H, Matsuda H. J Org Chem. 1986; 51:2177.
4. (a) Ghazanfarpour-Darjani M, Khodakarami A. Monatshefte fuer Chemie. 2016; 147:829;
(b) Yavari I, Ghazanfarpour-Darjani M. J Sulfur Chem. 2014; 35:477.
5. (a) Yano K, Amishiro N, Baba A, Matsuda H. Bull Chem Soc Jpn. 1991; 64:2661;
(b) Fujiwara M, Baba A, Matsuda H. J Heterocycl Chem. 1988; 25:1351;
(c) Baba A, Shibata I, Masuda K, Matsuda H. Synthesis 1985; 12:1144;
(d) Shibata I, Baba A, Iwasaki H, Matsuda H. J Org Chem. 1986; 51:2177.
6. (a) Fukuoka S, Kawamura M, Komiya K, Tojo M, Hachiya H, Hasegawa K, Aminaka M,
Okamoto H, Fukawa I, Konno S. Green Chem. 2003; 5:497;
19

ACCEPTED MANUSCRIPT
(b) Yoshida M, Ihara M. Chem-Eur J. 2004; 10:2886;
(c) Yamaguchi K, Ebitani K, Yoshida T, Yoshida H, Kaneda K. J Am Chem Soc. 1999;
121:4526;
(d) Yano T, Matsui H, Koike T, Ishiguro H, Fujihara H, Yoshihara M, Maeshima T. Chem
Commun. 1997; 12:1129;
(e) Kihara N, Hara N, Endo T. J Org Chem. 1993; 58:6198;
(f) Guo L-P, Wang C-M, Luo X-Y, Cui G-K, Li H-R. Chem Commun. 2010; 46:5960;
(g) Reithofer MR, Sum YN, Zhang Y-G. Green Chem. 2013; 15:2086;
(h) Tharun J, Mathai G, Kathalikkattil AC, Roshan R, Kwak JY, Park DW. Green Chem.
2013; 15:1673;
(i) Wu Z-L, Xie H-B, Yu X, Liu E-H. ChemCatChem. 2013; 5:1328;
(j) Liang S-G, Liu H-Z, Jiang T, Song J-L, Yang G-Y, Han B-X. Chem Commun. 2011;
47:2131.
7. (a) Wang Y-M, Li B, Wang H, Zhang Z-C, Lu X-B. Appl Organometal Chem. 2012;
26:614;
(b) Taguchi Y, Yasumoto M, Shibuya I, Suhara Y. Bull Chem Soc Jpn. 1989; 62:474;
(c) Jesudason MV, Owen LN. J Chem Soc Perkin Trans. 1974; 1:1443;
(d) Durden Jr. JA, Stambury Jr. HA, Catlette WH. J Am Chem Soc. 1960; 82:3082;
(e) Adachi N, Kida Y, Shikata K. J Polym Sci Polym Chem. 1977; 15:937;
(f) Hayashi S, Furukawa M, Wino Y, Nakao T, Nagato K, Chem Pharm Bull. 1971;
19:1594;
(g) Kim HS, Nguyen DQ, Cheong M, Kim H, Lee H, Ko NH, Lee JS. Appl Catal A-Gen.
2008; 337:168;
(h) Kihara N, Nakawaki Y, Endo T. J Org Chem. 1995; 60:473;
(i) Cao Y, Fuchigami T. Electrochim Acta. 2006; 51:2477.
8. (a) Choi W, Sanda F, Kihara N, Endo T. J Polym Sci Part A Polym Chem. 1997; 35:3853;
(b) Choi W, Sanda F, Endo, T. Macromolecules. 1998; 31:2454;
(c) Choi W, Sanda F, Endo T. Heterocycles. 2000; 52:125;
(d) Motokucho S, Sudo A, Sanda F, Endo T. Chem Commun. 2002; 1946;
(e) Motokucho S, Itagaki Y, Sudo A, Endo T, J Polym Sci Part A Polym Chem. 2005;
43:3711;
(f) Barton DHR, McCombie SW, J Chem Soc Perkin Trans. 1975; 1:1574;
(g) Keddie DJ, Moad G, Rizzardo E, Thang SH. Macromolecules. 2012; 45:5321.
9. (a) Ochiai B, Endo T. Prog Polym Sci. 2005; 30:183;
(b) Pandey KK. Coord Chem Rev. 1995; 140:37;
(c)Nakano K, Tatsumi G, Nozaki K. J Am Chem Soc. 2007; 129:15116.
20

ACCEPTED MANUSCRIPT
10. (a) Liu X, Cao C-S, Li Y-L, Guan P, Yang L-G, Shi Y-H. Synlett. 2012; 23:1343;
(b) Zhang H.-Z, Kong X-Q, Cao C-S, Pang G-S, Shi Y-H. J CO2 Util. 2016; 14:76;
(c) Xiao Y-Q, Kong X-Q, Xu Z-C, Cao C-S, Pang G-S, Shi Y-H. RSC Adv. 2015; 5:5032;
(d) Chao M, Zhang H-Z, Li Z-Y; Zhao Y-B, Cao C-S, Pang G-S, Shi Y-H. J CO2 Util.
2016; 16:412.
11. Halimehjani AZ, Ebrahimi F, Azizi N, Saidi MR. J Heterocycl Chem. 2009; 46:347.
21