Synthesis of Thiophosphates by Coupling of Phosphates with Bunte Salts under Mild Conditions

Article abstract of DOI:10.1055/s-0037-1609556

A simple, green, and efficient method has been developed for the preparation of thiophosphates with sodium S-benzyl thiosulfates. The method uses an NaBr-catalyzed coupling reaction of Bunte salts with phosphonates in the presence of an acid and hydrogen peroxide (30%), and the desired products were obtained in good yields.

Full text of DOI:10.1055/s-0037-1609556

SYNLETT
0
9
3
6
-
5
2
1
4
1
4
3
7
-
2
0
9
6
© Georg Thieme Verlag Stuttgart · New York
2018, 29, A–D
letter
A
en
C. Min et al.
Letter
Synlett
Synthesis of Thiophosphates by Coupling of Phosphates with
Bunte Salts under Mild Conditions
Cong Min
NaBr (10 mol%)
H2O2 (2.0 equiv)
O
O
Rongxing Zhang
Qian Liu
R1S SO3Na
R1S
P
R2
R2
R2
+
H
P
R2
CH3CN (1 mL)
HOAc (2.0 equiv)
19 examples (40–92%)
mild conditions
metal-free catalysis
H2O2 as a green oxidiant
Sen Lin*
R1 = Aryl, Alkyl
R2 = Alkoxy, Aryl
Zhaohua Yan*
College of Chemistry, Nanchang University, Nanchang,
Jiangxi 330031, P. R. of China
senlin@ncu.edu.cn
yanzh@ncu.edu.cn
Received: 10.05.2018
Accepted after revision: 13.06.2018
Published online: 14.08.2018
tensive application. Therefore, the development of a green
and efficient method for the preparation of thiophosphates
still remains extremely significant and challenging.
DOI: 10.1055/s-0037-1609556; Art ID: st-2018-u0298-l
O
Abstract A simple, green, and efficient method has been developed
for the preparation of thiophosphates with sodium S-benzyl thiosul-
fates. The method uses an NaBr-catalyzed coupling reaction of Bunte
salts with phosphonates in the presence of an acid and hydrogen perox-
ide (30%), and the desired products were obtained in good yields.
O
O
N
S
P
OMe
O
S
O
P
O
P
OMe
SEt
MeO
S
MeO
S
N
Cl
OMe
OMe
Azamethiphos
NH2
Demeton-S-methyl
Methylisosytox
Key words hydrogen peroxide, thiophosphates, Bunte salts, synthe-
sis, acids
O
+
H
N
O
N
I–
EtO
P
S
HO
P
S
OEt
OH
Thiophosphate compounds are vital in organic synthe-
sis because of their widespread applications in pharmaceu-
ticals, natural products, and biomolecules (Figure 1).1–3 In
recent years, a class of thiophosphates have been found to
be valuable intermediates that can be used to construct an
intramolecular pyrophosphate linkage or have been intro-
duced as acetylcholinesterase (ACHE) inhibitors and poten-
tial agents against HIV,4a,b and so on.4c,d Therefore, the con-
struction of P–S bonds has received comprehensive atten-
tion from synthetic scientists.5
Traditionally, thiophosphates are synthesized by nucle-
ophilic substitution of (RO)2P(O)Cl with RSH.6 However,
these methods present a potential safety hazard, are ineffi-
cient and environmentally unfriendly. Recently, some new
strategies have been reported for the synthesis of thiophos-
phate compounds.7–8 Han and co-workers9 described an ef-
ficient Pd-catalyzed coupling reaction for the construction
of P–S bonds between mercaptan and dialkyl phosphite. Ji-
ao’s group10 reported the synthesis of thiophosphate com-
pounds through cesium carbonate-catalyzed cross-dehy-
drogenative coupling of thiols with phosphite esters, and so
on.11 However, metal-catalyzed conditions and the use of
fetid thiol involved in these methods could limit their ex-
Echothiopate
Amifostine
Figure 1 Selected examples of pesticides and drugs containing thio-
phosphates
In recent years, Bunte salts (RSSO3Na) have been exten-
sively applied to organic synthesis because of their stability,
odorlessness, and easy availability.12–14 Herein, we report a
new method of NaBr-catalyzed formation of thiophosphate
with sodium S-benzyl thiosulfate and phosphite ester in the
presence of H2O2 as the oxidant and acetic acid as an addi-
tive.
Preliminary optimization of the reaction conditions was
carried out with diethyl phosphite (1a) and sodium S-ben-
zyl thiosulfate (2a) in the presence of sodium bromide as
the catalyst, H2O2 (30%) as the oxidant, and the yield of the
product (3aa) reached up to 70% (Table 1, entry 1). Then, we
explored the effects of various solvents (DMF, DCE, 1,4-di-
oxane) on the synthesis of thiophosphate from phosphite
ester and sodium thiosulfate at 80 °C, but all were less ef-
fective than MeCN (Table 1, entries 2–4). Additionally, low-
er yields of product 3aa were obtained when the reaction
temperature changed (Table 1, entries 5–7). We explored
the effect of the amount of oxidant (Table 1, entries 8–10)
© Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–D

B
C. Min et al.
Letter
Synlett
for thiophosphate synthesis, and H2O2 (2.0 equiv) provided
the best results. Next, production efficiency was improved
by adding acetic acid (2.0 equiv) as an addititive, and the
thiophosphate product could be isolated in 92% yield (Table
1, entries 10–12). We then screened a wide range of cata-
lysts, including TBAB, NBS, NCS, HBr, Br2, and NaI. However,
all of them only provided 3aa in lower yields (Table 1, en-
tries 13–17). Unsatisfactory results were obtained when
acetic acid and sodium bromide were replaced by hydrogen
bromide (Table 1, entries 18–20). Therefore, the optimized
reaction conditions were established as follows: phosphite
ester 1a (1.0 equiv), sodium S-benzyl thiosulfate (2a) (1.5
equiv), H2O2 (2.0 equiv) as the oxidant, acetic acid (2.0
equiv) as the additive, NaBr (20 mol%) as the catalyst,
CH3CN (1 mL) as the solvent at 80 °C for 0.5 h.
Dialkyl phosphites and various sodium S-benzyl thio-
sulfates were employed to construct S-benzyl thiophos-
phates under the optimized reaction conditions (Scheme
1). The corresponding products 3ab–af were detected in
moderate to good yields when dialkyl phosphites 1b–f and
sodium S-benzyl thiosulfate 2a were used as the substrates
in the reaction system. The reactions of 1a (R2 = OEt) and 1b
(R2 = OMe) with 2a afforded the corresponding products in
higher yields of 92 and 90%, respectively. Para-substituted
sodium S-benzyl thiosulfates with an electron-donating
group (Me) and dialkyl phosphite were employed and the
desired thiophosphates were obtained in moderate to good
yields (Scheme 1, 3ba, 3bc, 3be, and 3bf). However, sodium
S-p-fluorobenzyl thiosulfate 3c with 1a provided the corre-
sponding product in moderate yield (Scheme 1, 3ca). S-Ben-
zyl diphenyl thiophosphonate was merely obtained in a low
yield when diphenyl phosphonate was used as the sub-
strate (Scheme 1, 3ag).
Table 1 Optimization of the Reaction Conditionsa
O
P
H
O
catalyst
H2O2
S
EtO
OEt
S
P
OEt
+
NaBr
H+, H2O2
O
P
O
P
SO3Na
OEt
solvent
R2
R2
R1S SO3Na
R1S
R2
+
2a
1a
3aa
CH3CN
R2
H
1
2
3
Entry Catalyst
(mol%)
Oxidant
(equiv)
Solvent
Additive
(equiv)
Yield
(%)b
O
P
O
O
P
S
OMe
S
P
OEt
S
Oi-Pr
OMe
3ab 90%
OEt
Oi-Pr
3ac 80%
1
NaBr (20)
H2O2 (2.0)
H2O2 (2.0)
H2O2 (2.0)
H2O2 (2.0)
H2O2 (2.0)
H2O2 (2.0)
H2O2 (2.0)
H2O2 (1.0)
H2O2 (3.0)
H2O2 (2.0)
H2O2 (2.0)
H2O2 (2.0)
H2O2 (2.0)
H2O2 (2.0)
H2O2 (2.0)
H2O2 (2.0)
H2O2 (2.0)
H2O2 (2.0)
H2O2 (2.0)
H2O2 (2.0)
CH3CN
DMF
–
–
–
–
–
–
–
–
–
70
25
40
62
50
62
58
60
64
92
87
88
83
85
74
81
n.r.
78
75
83
3aa 92%
2
NaBr (20)
NaBr (20)
NaBr (20)
NaBr (20)
NaBr (20)
NaBr (20)
NaBr (20)
NaBr (20)
NaBr (20)
NaBr (20)
NaBr (20)
TBAB (20)
NBS (20)
NCS (20)
Br2 (10)
O
O
O
3
DCE
S
P
OBu
OBu
3ad 83%
S
P
Oi-Bu
S
P
OBn
OBn
3af 60%
4
1,4-dioxane
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
Oi-Bu
5c
6d
7e
8
3ae 75%
O
O
O
S
P
Ph
S
P
Oi-Pr
Oi-Pr
3bc 75%
S
P
OEt
Ph
OEt
3ag 45%
3ba 85%
9
O
O
O
10
HOAc (2.0)
HOAc (1.0)
HOAc (4.0)
HOAc (2.0)
HOAc (2.0)
HOAc (2.0)
HOAc (2.0)
HOAc (2.0)
HOAc (2.0)
–
S
P
OEt
S
P
Oi-Bu
S
P
OBn
OBn
3bf 50%
11
12
13
14
15
16
17
18
19
20
OEt
Oi-Bu
3be 79%
F
3ca 60%
Scheme 1 Reagents and conditions: 1 (0.2 mmol), 2 (0.3 mmol), NaBr
(20 mmol%), H2O2 (2.0 equiv), HOAc (2.0 equiv), and CH3CN (1.0 mL),
80 °C
Next, we investigated the synthesis of thiophosphate
with various Bunte salts (sodium S-phenyl thiosulfate, sodi-
um S-butyl thiosulfate, and sodium S-octyl thiosulfate etc.)
as substrates in this system. The results are shown in
Scheme 2. These compounds were obtained in moderate to
good yields and S-linear chain alkyl thiophosphates were
formed in higher yields than S-phenyl thiophosphates.
To explore the reaction mechanism, we carried out sev-
eral control experiments. The results are shown in Scheme
3. First of all, benzyl disulfide 4 was obtained in 93% yield
by oxidation of sodium S-benzyl thiosulfate with H2O2 in
acetonitrile (Scheme 3, a). Thiophosphate was isolated in
NaI (20)
HBr (20)
HBr (40)
HBr (100)
–
a Reagents and conditions: 1a (0.2 mmol), 2a (0.3 mmol), catalyst and oxi-
dant, solvent (1 mL), 0.5 h, 80 °C.
b Yield of isolated product; n.r. = no reaction.
c 20 °C.
d 60 °C.
e 100 °C.
© Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–D

C
C. Min et al.
Letter
Synlett
90% yield when dibenzyl sulfide 4 was used as the sulfur
source (Scheme 3, b) under the optimized conditions. How-
ever, thiophosphate was not obtained when the reaction of
sodium S-benzyl thiosulfate 2a was performed with phos-
phite ester 1a under the optimized conditions without H2O2
(Scheme 3, c). On the basis of the previous experimental re-
sults, we conducted an additional control experiment in
which DTBP was added to the reaction system, and the ex-
pected product 3aa was not formed (Scheme 3, d). Then,
the radical inhibitor (BHT) was incorporated under our op-
timal reaction conditions, and it had only little effect on the
yield (Scheme 3, e). The control experiments above show
that the presence of H2O2 plays a vital role in this method.
On the basis of the previous related reports and the
above mentioned control experiments15 a possible reaction
pathway is proposed in Scheme 4. Thiosulfate readily hy-
drolyzes in water and under heating, which results in the
formation of thiol and bisulfate anion. Thiol is then at-
tacked by hydrogen peroxide to generate disulfide. Next,
the electrophilic species R1SBr would emerge through the
reaction of disulfide with molecular bromine. Finally, R1SBr
attacks the phosphite ester and leads to the formation of
the P–S bonds. In the meanwhile, HBr is released in this
transformation. Then, intermediate Br2 is produced by H2O2
oxidation of HBr to close the catalytic cycle of bromine.
NaBr
O
P
R2
H+, H2O2
O
P
H
R1S SO3Na
R1S
R2
R2
R2
+
CH3CN
1
2
3
NaHSO4
H2O
O
O
P
O
R1S SO3Na
R1SH
H2O2
R1S SR1
n-C8H17
S
P OBn
n-C8H17
S
Oi-Pr
n-C8H17
S
P
OEt
OBn
Oi-Pr
OEt
H2O
Br2
3dc 70%
3da 78%
3df 50%
H2O
O
O
O
HBr
R1SBr
O
n-C8H17
S
P
Ph
n-C4H9
S
P
OEt
S
P
OEt
Ph
OEt
OEt
3dg 40%
Cl
3ea 71%
3fa 65%
O
P
R2
R2
R2
P
H
R2
O
P
SR1
S
OEt
Scheme 4 Plausible reaction mechanism
OEt
MeO
3ga 65%
In summary, we have developed a green and efficient
method for the synthesis of thiophosphate compounds16
through NaBr-catalyzed cross-coupling of phosphite esters
with various thiosulfates. A class of thiophosphate com-
pounds was obtained in good to excellent yields under mild
conditions, and a plausible reaction mechanism was pro-
posed. The simple method for the formation of P–S bonds is
expected to find wide application in the future
Scheme 2 Reagents and conditions: 1 (0.2 mmol), 2 (0.3 mmol), NaBr
(20 mmol%), H2O2 (2.0 equiv), HOAc (2.0 equiv), and CH3CN (1.0 mL),
80 °C
a)
H2O2, H2O
S
S
S
SO3Na
CH3CN
2a
4
4 93%
NaBr
O
b)
c)
O
P
H
H2O2
S
S
S
P
OEt
+
EtO
OEt
H+, CH3CN
OEt
Funding Information
1a
3aa 90%
We are grateful for the financial support from the National Natural
O
P
NaBr
S
Science Foundation of China (21302084).
N
oaitn
a
l
N
a
utra
l
S
ecin
c
e
F
o
u
n
d
oaitn
of
C
h
n
i
a
2(
1
3
0
2
0
8
4)
EtO
OEt
+
n.r.
H+, CH3CN
SO3Na
H
2a
1a
Supporting Information
NaBr
DTBP (2.0 equiv)
d)
O
S
Supporting information for this article is available online at
https://doi.org/10.1055/s-0037-1609556.
+
EtO
P
H
OEt
n.r.
SO3Na
H+, CH3CN
S
u
p
p
ortiInfogrmoaitn
S
u
p
p
o
nrtogI
f
rmoaitn
2a
1a
BHT (4.0 equiv)
H2O2, NaBr
References and Notes
O
e)
O
P
S
SO3Na
S
P
OEt
EtO
OEt
+
(1) (a) Beletskaya, I. P.; Ananikov, V. P. Chem. Rev. 2011, 111, 1596.
(b) Kumar, T. S.; Yang, T.; Mishra, S.; Cronin, C.; Chakraborty, S.;
Shen, J. B.; Liang, B. T.; Jacobson, K. A. J. Med. Chem. 2013, 56,
902. (c) Xie, R.; Zhao, Q.; Zhang, T.; Fang, J.; Mei, X.; Ning, J.;
H+, CH3CN
OEt
H
3aa 85%
2a
1a
Scheme 3 Control experiments
© Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–D

D
C. Min et al.
Letter
Synlett
Tang, Y. Bioorg. Med. Chem. 2013, 21, 278. (d) Wang, D. G.; Zhao,
J. L.; Xu, W. G.; Shao, C. W.; Shi, Z.; Li, L.; Zhang, X. H. Org.
Biomol. Chem. 2017, 15, 545.
(11) (a) Bai, J.; Cui, X. L.; Wang, H.; Wu, Y. J. Chem. Commun. 2014, 50,
8860. (b) He, W.; Hou, X.; Li, X. J.; Song, L.; Yu, Q. Wang. Z. W.
2017, 73, 3133.
(2) (a) Li, N. S.; Frederiksen, J. O.; Piccirilli, J. A. Acc. Chem. Res. 2011,
44, 1257. (b) Lauer, A. M.; Wu, J. Org. Lett. 2012, 14, 5138.
(c) Keough, D. T.; Spacek, P.; Hockova, D.; Tichy, T.; Vrbkova, S.;
Slavetınska, L.; Janeba, Z.; Naesens, L.; Edstein, M. D.; Chavchich,
M.; Wang, T. H.; Jersey, J. D.; Guddat, L. W. J. Med. Chem. 2013,
56, 2513. (d) Liu, N.; Mao, L. L.; Yang, B.; Yang, S. D. Chem.
Commun. 2014, 50, 10879. (e) Sun, J. G.; Yang, H.; Li, P.; Zhang,
B. Org. Lett. 2016, 18, 5114. (f) Mieko, A.; Tetsuya, O.; Masahiko,
Yi. Tetrahedron Lett. 2005, 46, 5669.
(3) (a) Piekutowska, M.; Pakulski, Z. Tetrahedron Lett. 2007, 48,
8482. (b) Ghanem, E.; Li, Y. C.; Xu, C. F.; Raushel, F. M. Biochem-
istry 2007, 46, 9032. (c) Shen, D. L.; Cao, Y. Y.; Zhu, F. X. Nongyao
2002, 41, 17. (d) Lauer, A. M.; Mahmud, F.; Wu, J. J. Am. Chem.
Soc. 2011, 133, 9119.
(4) (a) Fukuoka, M.; Shuto, S.; Minakawa, N.; Ueno, Y.; Matsuda, A.
J. Org. Chem. 2000, 65, 5238. (b) Fukuoka, M.; Shuto, S.;
Minakawa, N.; Ueno, Y.; Matsuda, A. Tetrahedron Lett. 1999, 40,
5361. (c) Huang, L. J.; Zhao, Y. Y.; Yuan, L.; Min, J. M.; Zhang, L. H.
J. Med. Chem. 2002, 45, 5340. (d) Kaboudin, A.; Emadi, S.;
Hadizadeh, A. Bioorg. Chem. 2009, 37, 101.
(12) (a) Bunte, H. Chem. Ber. 1874, 7, 646. (b) Liu, F. M.; Yi, W. B. Org.
Chem. Front. 2018, 5, 428. (c) Reeves, J. T.; Camara, K.; Han, Z. X.
S.; Xu, Y. B.; Lee, H.; Busacca, C. A.; Senanayake, C. H. Org. Lett.
2014, 16, 1196. (d) Lin, Y. M.; Lu, G. P.; Cai, C.; Yi, W. B. RSC. Adv.
2015, 5, 27107. (e) Liu, B. B.; Chu, X. Q.; Liu, H.; Yin, L.; Wang, S.
Y.; Ji, S. J. J. Org. Chem. 2017, 82, 10174.
(13) (a) Qiao, Z. J.; Jiang, X. F. Org. Lett. 2016, 18, 1550. (b) Qi, H.;
Zhang, T. X.; Wan, K. F.; Luo, M. M. J. Org. Chem. 2016, 81, 4262.
(c) Qiao, Z. J.; Ge, N. Y.; Jiang, X. F. Chem. Commun. 2015, 51,
10295. (d) Zhang, R. X.; Yan, Z. H.; Lin, S. Synlett 2018, 29, 336.
(e) Qiao, Z. J.; Jiang, X. F. Org. Biomol. Chem. 2017, 15, 1942.
(f) Liu, H.; Jiang, X. F. Chem. Asian. J. 2013, 8, 2546.
(14) (a) Li, Y. M.; Wang, M.; Jiang, X. F. ACS Catal. 2017, 7, 7587. (b) Li,
Y. M.; Xie, W. S.; Jiang, X. F. Chem. Eur. J. 2015, 21, 16059.
(c) Xiao, X.; Feng, M. H.; Jiang, X. F. Chem. Commun. 2015, 51,
4208. (d) Zhang, Y. H.; Li, Y. M.; Zhang, X. M.; Jiang, X. F. Chem.
Commun. 2015, 51, 941. (e) Li, Y. M.; Pu, J. H.; Jiang, X. F. Org.
Lett. 2014, 16, 2692. (f) Qiao, Z. J.; Wei, J. P.; Jiang, X. F. Org. Lett.
2014, 16, 1212. (g) Qiao, Z. J.; Liu, H.; Xiao, X.; Fu, Y. N.; Wei, J. P.;
Li, Y. X.; Jiang, X. F. Org. Lett 2013, 15, 2594.
(5) (a) Pekutowska, M.; Pakulski, Z. Carbohydr. Res. 2008, 343, 785.
(b) Wang, G.; Shen, R.; Xu, Q.; Goto, M.; Zhao, Y.; Han, L. B. J. Org.
Chem. 2010, 75, 3890. (c) Wang, J.; Huang, X.; Ni, Z.; Wang, S.;
Wu, J.; Pan, Y. Green Chem. 2015, 17, 314. (d) Kaboudin, B.;
Abedi, Y.; Kato, J.-Y.; Yokomatsu, T. Synthesis 2013, 45, 2323.
(e) Panmand, D. S.; Tiwari, A. D.; Panda, S. S.; Monbaliu, J. C. M.;
Beagle, L. K.; Asiri, A. M.; Stevens, C. V.; Steel, P. J.; Hall, C. D.;
Katritzky, A. R. Tetrahedron Lett. 2014, 55, 5898.
(6) (a) Liu, T.; Neverov, A. A.; Tasang, J. S. W.; Brown, R. S. Org.
Biomol. Chem. 2005, 3, 1525. (b) Li, J. C.; Meng, F. H.; Wang, H.
M.; Xiao, J. H. Tetrahedron 2016, 72, 706.
(7) (a) Liu, Y. C.; Lee, C. F. Green Chem. 2014, 16, 357. (b) Babaev, B.
N.; Asanova, M. Uzb. Khim. Zh. 1988, 5, 17.
(8) (a) Alcaide, A.; Llebaria, A. J. Org. Chem. 2014, 79, 2993. (b) Sun,
J. G.; Weng, W. Z.; Li, P.; Zhang, B. Green. Chem. 2017, 19, 1128.
(c) Grounds, H.; Ermanis, K.; Newgas, S. A.; Porter, M. J. J. Org.
Chem. 2017, 82, 12735. (d) Wang, J. C.; Huang, X.; Ni, Z. Q.;
Wang, S. C.; Pan, Y. J.; Wu, J. Tetrahedron 2015, 71, 7853.
(9) Zhu, Y. Y.; Chen, T. Q.; Li, S.; Shimada, S.; Han, L. B. J. Am. Chem.
Soc. 2016, 138, 5825.
(15) (a) Zhang, R. X.; Yan, Z. H.; Wang, D. Y.; Wang, Y. X.; Lin, S.
Synlett 2017, 28, 1195. (b) Li, J.; Cai, Z. J.; Wang, S. Y.; Ji, S. J. Org.
Biomol. Chem. 2016, 14, 9384. (c) Zhang, R. X.; Jin, S. Z.; Wang, Y.
X.; Lin, S.; Yan, Z. H. Tetrahedron Lett. 2018, 59, 841.
(16) Phosphorothioates 3; General Procedure
Dialkyl phosphonate 1 (0.2 mmol) was added to a stirred
mixture of sodium S-benzyl thiosulfate 2 (0.3 mmol), NaBr
(0.04 mmol, 20 mol%), and HOAc (2.0 equiv) in CH3CN (1 mL).
H2O2 (2.0 equiv) was added and the reaction mixture was
stirred for 0.5 h at 80 °C. After the reaction was completed, it
was cooled down to r.t. The resulting solution was diluted and
extracted with EtOAc (3 ×10 mL). The organic layer was washed
with saturated salt water and dried with anhydrous sodium sul-
fate. The pure product 3 was obtained by column chromatography.
Compound 3bc was obtained in 77% yield (46.6 mg) according
to the general procedure as a colorless oil. 1H NMR (400 MHz,
CDCl3): δ = 7.27–7.19 (m, 2 H), 7.10 (d, J = 7.8 Hz, 2 H), 4.79–
4.55 (m, 2 H), 4.01 (d, J = 12.3 Hz, 2 H), 2.31 (s, 3 H), 1.32 (d, J =
6.2 Hz, 6 H), 1.28 (d, J = 6.2 Hz, 6 H) ppm. 13C NMR (101 MHz,
CDCl3): δ = 137.27, 134.24, 129.28, 128.79, 72.59 (d, J = 6.3 Hz),
34.96 (d, J = 3.8 Hz), 23.81 (d, J = 4.1 Hz), 23.51 (d, J = 5.6 Hz),
21.08 ppm. 31P NMR (243 MHz, CDCl3): δ = 24.38 ppm. HRMS
(ESI+): m/z calcd for C14H23O3PS [M + H]+: 303.1178; found:
303.1193.
(10) Song, S.; Zhang, Y. Q.; Yeerlan, A.; Zhu, B. C.; Liu, J. Z.; Jiao, N.
Angew. Chem. Int. Ed. 2017, 129, 2527.
© Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–D