Visible-Light-Promoted Difunctionalization of Olefins Leading to α-Thiocyanato Ketones

Article abstract of DOI:10.1055/s-0037-1609443

A simple and convenient visible-light-induced difunctionalization of alkenes with ammonium thiocyanate and dioxygen has been developed at room temperature. A series of α-thiocyanato ketones could be easily and efficiently obtained in moderate to good yields through the formation of C-S and C=O bonds simply by using nontoxic and inexpensive Na ₂ -Eosin Y as a photocatalyst.

Full text of DOI:10.1055/s-0037-1609443

SYNLETT
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© Georg Thieme Verlag Stuttgart · New York
2018, 29, A–F
letter
A
en
G. Nan, H. Yue
Letter
Synlett
Visible-Light-Promoted Difunctionalization of Olefins Leading to
α-Thiocyanato Ketones
Guangming Nan*a
Huilan Yue*b
a University and College Key Lab of Natural Product Chemistry and
Application in Xinjiang, School of Chemistry and Environmental
Science, Yili Normal University, Yining 835000, China
nanguangming02@sohu.com
b Key Laboratory of Tibetan Medicine Research, Northwest Institute
of Plateau Biology, Chinese Academy of Sciences and Qinghai Pro-
vincial Key Laboratory of Tibetan Medicine Research, Qinghai
810008, China
O
Na2-Eosin Y (2 mol%)
SCN
R2
R1
+
NH4SCN
+ O2
R1
1 = aryl
3W blue LED
R2
CH3CN, r.t., 5 h
R
18 examples
metal-free
room temperature
R2 = alkyl, H
49–82% yields
simple operation
eco-benign energy source
hlyue@nwipb.cas.cn
dioxygen as oxygen source
Received: 07.01.2018
Accepted after revision: 08.03.2018
Published online: 23.04.2018
tion of styrenes in the presence of a stoichiometric amount
of cerium(IV) ammonium nitrate (CAN), cis-1,4-bis(triph-
enylphosphonium)-2-buteneperoxodisulfate (BTPBPD), or
AcOH have also been developed.9 Nevertheless, many of
these methods still involve multi-step synthetic sequences,
the use of a large excess of expensive and strong oxidants,
or toxic metal catalysts and metal thiocyanates, which may
limit their practical applications in synthetic and pharma-
ceutical chemistry. Therefore, the development of mild,
convenient, economic, and environmentally benign meth-
ods to prepare α-thiocyanato ketones is still highly desir-
able.
DOI: 10.1055/s-0037-1609443; Art ID: st-2018-w0014-l
Abstract A simple and convenient visible-light-induced difunctional-
ization of alkenes with ammonium thiocyanate and dioxygen has been
developed at room temperature. A series of α-thiocyanato ketones
could be easily and efficiently obtained in moderate to good yields
through the formation of C–S and C=O bonds simply by using nontoxic
and inexpensive Na2-Eosin Y as a photocatalyst.
Key words visible-light catalysis, difunctionalization, alkenes, ammo-
nium thiocyanate, α-thiocyanato ketones
Visible-light photoredox catalysis has attracted great at-
tention as a powerful tool to develop sustainable synthetic
processes because of its advantageous properties: clean and
safe application and easy availability of visible light, which
is a renewable energy source.10 In recent years, various syn-
thetically useful chemical transformations have been suc-
cessfully established by visible-light-driven catalysis under
the mild conditions.11 On the other hand, the direct utiliza-
tion of dioxygen as an oxidant and oxygen source in organic
synthesis meets the demands of green chemistry because
of its economic and environmentally benign features. Visi-
ble-light photoredox catalysis has opened up a new and at-
tractive avenue for aerobic oxidation, where molecular oxy-
gen is usually used as an oxidant to regenerate the photore-
dox catalyst after its reductive quenching to finish the
catalytic cycle.12
As an important functionality, the thiocyanato group is
widely present in a number of natural products and biolog-
ically-active compounds.1 Furthermore, organic thiocya-
nates are of great importance in various areas of organo-
sulfur chemistry because they are key synthetic intermedi-
ates to access diverse valuable sulfur-containing
compounds.2 In particular, α-thiocyanato carbonyl com-
pounds can serve as versatile precursors for the construc-
tion of sulfur-containing heterocycles such as thiazoles and
2-amino-1,3-thiazines,3 some of which are associated with
herbicidal and other useful biological activities.4 As a con-
sequence, considerable research efforts have been dedicat-
ed to construct α-thiocyanato ketones. In general, α-thiocy-
anato ketones are prepared by the nucleophilic reaction of
the thiocyanate anion with halocarbonyl compounds5 or α-
tosyloxycarbonyls.6 However, these classical methods usu-
ally require harsh reaction conditions and suffer from low
yields that are due to the poor nucleophilicity of the thiocy-
anate anion. In recent years, alternative methods such as
the direct α-thiocyanation of ketones mediated by I2,7a het-
eropolyacid,7b FeCl3,7c NBS,7d and copper,7e the oxidative
thiocyanation of enol ethers,8 and the thiocyanation reac-
O
Na2-Eosin Y (2 mol%)
3W blue LEDs
SCN
R2
NH4SCN
+ O2
+
R1
R1
CH3CN, r.t., 5 h
R2
Scheme 1 Visible-light-induced difunctionalization of alkenes with
ammonium thiocyanate and dioxygen
© Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–F

B
G. Nan, H. Yue
Letter
Synlett
Herein, we report a mild and convenient visible-light-
enabled method for the construction of α-thiocyanato car-
bonyl compounds through Na2-Eosin Y catalyzed difunc-
tionalization of alkenes with ammonium thiocyanate and
dioxygen (Scheme 1), in which the C−S and C=O bonds are
formed in a one-pot procedure under mild and metal-free
conditions.
We started our investigation by using the combination
of styrene (1a), NH4SCN, and Eosin B (2 mol%) in MeCN (5
mL) under O2 at room temperature as the model reaction.
The reaction was conducted under irradiation with a 3W
blue LED lamp. To our delight, the desired α-thiocyanato ke-
tone 4a was obtained in 36% yield after five hours (Table 1,
entry 1). In the screening of photocatalysts Na2-Eosin Y was
the best one leading to the desired product 4a in 79% yield
(Table 1, entry 7), while others such as Rhodamine B, Acri-
dine Red, Rose Bengal, Eosin Y, and Ru(bpy)3Cl2 were less ef-
fective in this transformation (Table 1, entries 2−6). The
choice of solvent was also crucial
for this oxythiocyanation reaction. Replacing CH3CN
with other solvents dramatically decreased the yield of 4a
(Table 1, entries 8−17). Low to moderate yields were ob-
tained when the reaction was carried out in ether solvent
such as THF, DME, or 1,4-dioxane (Table 1, entries 8−10).
DCE, toluene, DMF, H2O, acetone, EtOH, and CH3CN/H2O
all resulted in no transformation or low efficiency (Table 1,
entries 11−17). Increasing or decreasing the loading of
Na2-Eosin Y failed to improve the reaction efficiency (Table
1, entries 18−19). Furthermore, replacing NH4SCN by KSCN
gave the desired product 4a in only 34% yield (Table 1, entry
20). Moreover, the target product could also be isolated in
moderate yield when the model reaction was carried out
under air (Table 1, entry 21). Notably, only a lower amount
of the desired product was obtained when the reaction was
conducted in absence of the photocatalyst (Table 1, entry
22). In contrast, the oxythiocyanation of alkene did not at
all occur in the dark (Table 1, entry 23).
Table 1 Optimization of Reaction Conditionsa
O
photocatalyst (mol%)
3W blue LEDs
SCN
+
NH4SCN
+ O2
solvent, r.t., 5 h
1a
2
3
4a
Structures of photocatalysts:
Cl
Cl
Cl
Cl
COOH
Cl
COONa
I
I
N
O
N
H
• HCl
N
O
N
NaO
O
O
I
I
Bengal Rose
Acridine Red
Rhodamine B
COONa
Br
COOH
COONa
Br
Br
Br
O2N
NO2
NaO
O
O
HO
O
O
NaO
O
O
Br
Br
Br
Br
Br
Br
Eosin B
Eosin Y
Na2-Eosin Y
Entry
Photocatalyst (mol%)
Solvent
Yield (%)b
1
2
3
4
5
6
7
Eosin B (2)
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
36
34
33
33
41
56
79
Rhodamine B (2)
Acridine Red (2)
Rose Bengal (2)
Eosin Y (2)
Ru(bpy)3Cl2 (2)
Na2-Eosin Y (2)
© Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–F

C
G. Nan, H. Yue
Letter
Synlett
Table 1 (continued)
Entry
Photocatalyst (mol%)
Solvent
Yield (%)b
8
9
Na2-Eosin Y (2)
Na2-Eosin Y (2)
Na2-Eosin Y (2)
Na2-Eosin Y (2)
Na2-Eosin Y (2)
Na2-Eosin Y (2)
Na2-Eosin Y (2)
Na2-Eosin Y (2)
Na2-Eosin Y (2)
Na2-Eosin Y (2)
Na2-Eosin Y (5)
Na2-Eosin Y (1)
Na2-Eosin Y (2)
Na2-Eosin Y (2)
−
THF
12
16
54
0
DME
10
11
12
13
14
15
16
17
18
19
20
21
22
23
1,4-dioxane
DCE
toluene
DMF
0
0
H2O
0
EtOH
trace
trace
18
49
63
34c
50d
22
0e
acetone
CH3CN/H2O
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
CH3CN
Na2-Eosin Y (2)
a Reaction conditions: 1a (0.2 mmol), 2 (0.4 mmol), photocatalyst (1–5 mol%), solvent (5 mL), 3W blue LED lamps, r.t., O2, 5 h.
b Isolated yields based on 1a.
c KSCN was used instead of NH4SCN.
d Under air.
e In the dark.
After the establishment of the optimal reaction condi-
tions, the substrate scope in this visible-light-promoted di-
functionalization of alkenes was examined. As listed in
Scheme 2, in general, reactions of aromatic alkenes contain-
ing electron-donating or electron-withdrawing groups with
ammonium thiocyanate and dioxygen worked well under
the standard conditions and their corresponding α-thiocy-
anato ketones were obtained in moderate to good yields.
The reaction efficiency was not obviously affected by the
steric effect, and substrates bearing a methyl group in the
para, meta, or ortho position of the aryl ring were all suit-
able for this reaction (4b–d). A series of functionalities such
as methoxy, chloromethyl, acetoxy, or halogen groups sur-
vived well leading to 4f–n, which could be potentially em-
ployed for further modifications. 2-Vinylnaphthalene also
performed well in this reaction to give the expected prod-
uct 4o in 82% yield. Notably, an internal aromatic alkene
such as (E)-prop-1-enylbenzene could smoothly be con-
verted into the desired α-thiocyanato ketone 4p in 51%
yield. Nevertheless, none of the desired products (4q and
4r) were detected when stilbene and an aliphatic alkene
such as hex-1-ene were employed in this reaction system.
Subsequently, we turned our attention to the possible
reaction mechanism. As demonstrated in Scheme 3 (a), the
model reaction was significantly inhibited when 2,2,6,6-te-
tramethyl-1-piperidinyloxy (TEMPO) or 2,6-di-tert-butyl-
4-methylphenol (BHT) was added under standard condi-
tions, indicating that a radical process might be involved in
this transformation. Furthermore, only a trace amount of
product 4a was detected when the model reaction was car-
ried out under a nitrogen atmosphere (Scheme 3, b), which
suggests that dioxygen should be the key oxidant and oxy-
gen source in the present reaction system. Moreover, to cer-
tify the effect of photo irradiation, on/off visible-light irra-
diation experiments were performed. The result demon-
strated that the continuous irradiation of visible-light is
essential for this reaction (Figure 1).
Figure 1 On/off experiments
© Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–F

D
G. Nan, H. Yue
Letter
Synlett
Na2-Eosin Y (2 mol%)
3W blue LEDs
O
Na2-Eosin Y (2 mol%)
3W blue LEDs
O
SCN
SCN (a)
R2
Ph
R1
O
NH4SCN
+
+ O2
NH4SCN
+ O2
+
Ph
R1
CH3CN, r.t., 4 h
CH3CN, r.t., 5 h
R2
1
2
3
4
TEMPO (2 equiv)
BHT (2 equiv)
4a (0%)
O
O
4a (trace)
SCN
SCN
SCN
SCN
Na2-Eosin Y (2 mol%)
3W blue LEDs
O
(b)
SCN
4a (79%)
4b (70%)
4c (78%)
NH4SCN
+
Ph
Ph
CH3CN, r.t., 4 h, N2
O
4a (trace)
O
O
SCN
SCN
Scheme 3 Prelimininary mechanistic study
MeO
4d (74%)
4e (69%)
4f (51%)
O
O
O
SCN
O
SCN
SCN
Cl
F
O
4g (72%)
4h (49%)
4i (79%)
O
O
O
F
SCN
SCN
Cl
SCN
Cl
4j (71%)
4k (68%)
4l (72%)
O
O
O
SCN
SCN
SCN
Br
Figure 2 Quenching of Na2-Eosin Y fluorescence emission in the pres-
Br
ence of NH4SCN
4m (64%)
4n (62%)
4o (82%)
O
O
O
SCN
SCN
SCN
4q (0%)
4p (51%)
4r (0%)
Scheme 2 Results for visible-light-induced difunctionalization of
alkenes leading to α-thiocyanato ketones. Reaction conditions: 1 (0.2
mmol), 2 (0.4 mmol), Na2-Eosin Y (2 mol%), CH3CN (5 mL), 3W blue LED
lamps, r.t., O2, 5 h. Isolated yields are based on 1.
In addition, an energy transfer process between Na2-Eo-
sin Y and NH4SCN was proved by a series of fluorescence-
quenching (Stern–Volmer) experiments. As shown in Fig-
ures 2 and 3, the emission intensity of excited Na2-Eosin Y
gradually decreased along with increasing concentration of
NH4SCN. On the contrary, when Na2-Eosin Y and styrene 1a
were mixed separately, such effect was not observed (see
Supporting Information). These results strongly suggest
that a single-electron transfer process occurred between
Na2-Eosin Y and NH4SCN under the standard reaction con-
ditions.
Figure 3 Stern–Volmer plot
gle-electron transfer (SET) from thiocyanate anion 2 to Na2-
Eosin Y* gives the thiocyanate radical 5 and Na2-Eosin Y•−
radical anion.13 The oxidation of Na2-Eosin Y•− by dioxygen
forms the ground-state Na2-Eosin Y and O2•−. Then, the se-
lective addition of thiocyanate radical 5 to alkene 1 produc-
•−
On the basis of the above results and previous re-
ports,9,13–15 a possible reaction mechanism is described in
Scheme 4. Initially, Na2-Eosin Y* is generated from Na2-Eo-
sin Y in the presence of blue LED light. Subsequently, a sin-
es alkyl radical 6. Next, the interaction of radical 6 with O2
or O2 and NH4+ would lead to the formation of hydroperox-
ide intermediate 7.14 Finally, the elimination of water from
7 affords the corresponding product 4.9,15
© Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–F

E
G. Nan, H. Yue
Letter
Synlett
R2
2003, 68, 9116. (g) Ke, F.; Qu, Y.-Y.; Jiang, Z.-Q.; Li, Z.-K.; Wu, D.;
Zhou, X.-G. Org. Lett. 2011, 13, 454. (h) Jansa, P.; Cechova, L.;
Dracinsky, M.; Janeba, Z. RSC Adv. 2013, 3, 2650.
R1
SCN
R1
1
SCN
SCN
R2
6
5
2
(3) (a) Wood, J. L. Organic Reactions;
3
V
o.
l
Adams, R., Ed.; Chap. 6; John
+
NH4
Wiley & Sons: New York, 1946. (b) Metzer, J. B. Comprehensive
Na2-Eosin Y*
Na2-Eosin Y*
O2
O
2 /O2
Heterocyclic Chemistry;
6
V
o.
l
Katritzky, A., Ed.; Pergamon: Oxford,
1984, 235. (c) Yadav, L. D. S.; Patel, R.; Rai, V. K.; Srivastava, V. P.
Tetrahedron Lett. 2007, 48, 7793.
NH3
hv
HO
(4) Kawamura, S.; Izumi, K.; Satoh, J.; Sanemitsu, Y.; Hamada, T.;
Shibata, H.; Satoh, R. Eur. Patent Appl. E. P. 446802, 1991.
O
O2
Na2-Eosin Y
O
SCN
R1
SCN
R1
– H2O
(5) Dittmer, D. C. Comprehensive Hetrocyclic Chemistry;
7
V
o.
l
Katritzky,
4
R2
7
R2
A., Ed.; Pergamon: Oxford, 1984, 178.
(6) Prakash, O.; Saini, N. Synth. Commun. 1993, 23, 1455.
Scheme 4 Postulated reaction pathway
(7) (a) Yadav, J. S.; Reddy, B. V. S.; Reddy, U. V. S.; Krishna, A. D. Tet-
rahedron Lett. 2007, 48, 5243. (b) Chaskar, A. C.; Yadav, A. A.;
Langi, B. P.; Murugappan, A.; Shah, C. Synth. Commun. 2010, 40,
2850. (c) Yadav, J. S.; Reddy, B. V. S.; Reddy, U. V. S.; Chary, D. N.
Synthesis 2008, 8, 1283. (d) Reddy, B. V. S.; Reddy, S. M. S.;
Madan, C. Tetrahedron Lett. 2011, 52, 1432. (e) Zhang, G.-F.;
Wang, Y.; Ding, C.-Y.; Wen, X.; Wu, J. Faming Zhuanli Shenqing
2012, CN 102320909A.
(8) (a) Prakash, O.; Kaur, H.; Batra, H.; Singh, S. P.; Moriarty, R. A. J.
Org. Chem. 2001, 66, 2019. (b) Prakash, O.; Rani, N.; Sharma, V.;
Moriarty, R. M. Synlett 1997, 1255. (c) Iranpoor, N.; Firouzabadi,
H.; Shaterian, H. Synlett 2000, 65. (d) Tanabe, Y.; Makita, T.;
Mori, K. Chem. Lett. 1994, 2275.
In summary, a facile and efficient visible-light-enabled
method has been developed for the construction of α-thio-
cyanato ketones through Na2-Eosin Y catalyzed difunction-
alization of alkenes with ammonium thiocyanate and di-
oxygen at room temperature.16 Such a “green” protocol pro-
vides an attractive approach to access various α-
thiocyanato ketones because of its operational simplicity,
mild reaction conditions, eco-friendly energy source, and
cheap and nontoxic catalyst. Further studies on the scope
and application of this reaction are underway in our labora-
tory.
(9) (a) Nair, V.; Nair, L. G.; George, T. G.; Augustine, A. Tetrahedron
2000, 56, 7607. (b) Badri, R.; Gorjizadeh, M. Synth. Commun.
2012, 42, 2058. (c) Liu, K.; Li, D.-P.; Zhou, S.-F.; Pan, X.-Q.;
Shoberu, A.; Zou, J.-P. Tetrahedron 2015, 71, 4031.
Funding Information
(10) Selected examples: (a) Nicewicz, D. A.; MacMillan, D. W. C.
Science 2008, 322, 77. (b) Prier, C. K.; Rankic, D. A.; MacMillan,
D. W. C. Chem. Rev. 2013, 113, 5322. (c) Yoon, T. P.; Ischay, M. A.;
Du, J. Nat. Chem. 2010, 2, 527. (d) Schultz, D. M.; Yoon, T. P.
Science 2014, 343, 6174. (e) Shi, L.; Xia, W. Chem. Soc. Rev. 2012,
41, 7687. (f) Xuan, J.; Xiao, W.-J. Angew. Chem. Int. Ed. 2012, 51,
6828. (g) Chen, J.-R.; Hu, X.-Q.; Lu, L.-Q.; Xiao, W.-J. Chem. Soc.
Rev. 2016, 45, 2044. (h) Skubi, K. L.; Blum, T. R.; Yoon, T. P. Chem.
Rev. 2016, 116, 10035. (i) Romero, N. A.; Nicewicz, D. A. Chem.
Rev. 2016, 116, 10075.
This work was supported by the Opening Project of Key Laboratory at
Universities of Education Department of Xinjiang Uygur Autonomous
Region (No. 2017YSHXZD04).
)(
Supporting Information
Supporting information for this article is available online at
https://doi.org/10.1055/s-0037-1609443.
S
u
p
p
ortioInfgrmoaitn
S
u
p
p
ortiInfogrmoaitn
(11) Selected examples: (a) Shi, Q.; Li, P.; Zhu, X.; Wang, L. Green
Chem. 2016, 18, 4916. (b) Zhang, L.; Yi, H.; Wang, J.; Lei, A. Green
Chem. 2016, 18, 5122. (c) Ghogare, A. A.; Greer, A. Chem. Rev.
2016, 116, 9994. (d) Shyam, P. K.; Jang, H.-Y. J. Org. Chem. 2017,
82, 1761. (e) Hu, X.; Zhang, G.; Bu, F.; Lei, A. ACS Catal. 2017, 7,
1432. (f) Wei, W.; Cui, H.; Yang, D.; Yue, H.; He, C.; Zhang, Y.;
Wang, H. Green Chem. 2017, 19, 5608. (g) Li, X.; Fang, X.;
Zhuang, S.; Liu, P.; Sun, P. Org. Lett. 2017, 19, 3580.
(12) (a) Zou, Y.-Q.; Chen, J.-R.; Liu, X.-P.; Lu, L.-Q.; Davis, R. L.;
Jørgensen, K. A.; Xiao, W.-J. Angew. Chem. Int. Ed. 2012, 51, 784.
(b) Ravelli, D.; Fagnoni, M.; Albini, A. Chem. Soc. Rev. 2013, 42,
97. (c) Keshari, T.; Yadav, V. K.; Srivastava, V. P.; Yadav, L. D. S.
Green Chem. 2014, 16, 3986. (d) Shi, Q.; Li, P.; Zhu, X.; Wang, L.
Green Chem. 2016, 18, 4916. (e) Zhang, L.; Yi, H.; Wang, J.; Lei, A.
Green Chem. 2016, 18, 5122. (f) Cui, H.; Wei, W.; Yang, D.;
Zhang, Y.; Zhao, H.; Wang, L.; Wang, H. Green Chem. 2017, 19,
3520. (g) Shyam, P. K.; Jang, H.-Y. J. Org. Chem. 2017, 82, 1761.
(13) (a) Mitra, S.; Ghosh, M.; Mishra, S.; Hajra, A. J. Org. Chem. 2015,
80, 8275. (b) Fan, W.; Yang, Q.; Xu, F.; Li, P. J. Org. Chem. 2014,
79, 10588. (c) Yadav, A. K.; Yadav, L. D. S. Green Chem. 2015, 17,
3515. (d) Hari, D. P.; Konig, B. Chem. Commun. 2014, 50, 6688.
(e) Kundu, D.; Ahammed, S.; Ranu, B. C. Org. Lett. 2014, 16,
1814. (f) Zhang, G.; Zhang, L.; Yi, H.; Luo, Y.; Qi, X.; Tung, C.-H.;
References and Notes
(1) (a) Mehta, R. G.; Liu, J.; Constantinou, A.; Thomas, C. F.;
Hawthorne, M.; You, M.; Gerhüser, C.; Pezzuto, J. M.; Moon, R.
C.; Moriarty, R. M. Carcinogenesis 1995, 16, 399. (b) Yasman, Y.;
Edrada, R. A.; Wray, V.; Proksch, P. J. Nat. Prod. 2003, 66, 1512.
(c) Elhalem, E.; Bailey, B. N.; Docampo, R.; Ujváry, I.; Szajnman,
S. H.; Rodriguez, J. B. J. Med. Chem. 2002, 45, 3984. (d) Kokorekin,
V. A.; Terent’ev, A. O.; Ramenskaya, G. V.; Grammatikova, N. E.;
Rodionova, G. M.; Ilovaiskii, A. I. Pharm. Chem. J. 2013, 47, 422.
(e) Promkatkaew, M.; Gleeson, D.; Hannongbua, S.; Gleeson, M.
P. Chem. Res. Toxicol. 2014, 27, 51. (f) Roberts, D. W.; Aptula, A.
O. Chem. Res. Toxicol. 2014, 27, 240.
(2) (a) Still, I. W. J.; Toste, F. D. J. Org. Chem. 1996, 61, 7677.
(b) Kianmehr, E.; Ghanbari, M.; Niri, M. N.; Faramarzi, R. J. Comb.
Chem. 2010, 12, 41. (c) Toste, F. D.; LaRonde, F.; Still, I. W. J. Tet-
rahedron Lett. 1995, 17, 2949. (d) Erian, A. W.; Sherif, S. M. Tet-
rahedron 1999, 55, 7957. (e) Demko, Z. P.; Sharpless, K. B. Org.
Lett. 2001, 3, 4091. (f) Wei, Z. L.; Kozikowski, A. P. J. Org. Chem.
© Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–F

F
G. Nan, H. Yue
Letter
Synlett
Wu, L.-Z.; Lei, A. Chem. Commun. 2016, 52, 10407. (g) Hu, B.; Li,
Y.; Dong, W.; Ren, K.; Xie, X.; Wan, J.; Zhang, Z. Chem. Commun.
2016, 52, 3709. (h) Cao, S.; Zhong, S.; Xin, L.; Wan, J.-P.; Wen, C.
ChemCatChem 2015, 7, 1478. (i) Pan, X.-Q.; Lei, M.-Y.; Zou, J.-P.;
Zhang, W. Tetrahedron Lett. 2009, 50, 347.
(16) Preparation of 1-Phenyl-2-thiocyanatoethanone (4a)
To a solution of NH4SCN (2) (30.4 mg, 0.4 mmol) and Na2-EosinY
(2.8 mg, 0.004 mmol, 2 mol%) in CH3CN (5 mL) was added
alkene 1a (20.8 mg, 0.2 mmol). The reaction mixture was
stirred under the irradiation of 3W blue LED under an oxygen
atmosphere at r.t. for 5 h. After completion of the reaction, the
solution was concentrated under vacuum. The residue was puri-
fied by using a mixture of ethyl acetate and petroleum ether
(1:10) as eluent to give the desired product 4a. Yield: 30 mg
(79%). 1H NMR (CDCl3, 500 MHz, ppm): δ = 7.95 (d, J = 8.0 Hz, 2
H), 7.68 (t, J = 7.3 Hz, 1 H), 7.54 (t, J = 7.7 Hz, 2 H), 4.75 (s, 2 H).
13C NMR (CDCl3, 125 MHz, ppm): δ = 190.8, 134.8, 134.0, 129.2,
128.5, 111.9, 43.0. HRMS: m/z [M + Na]+ calcd for C9H7NOSNa:
200.0146; found 200.0149.
(14) (a) Bu, M.; Lu, G.; Cai, C. Catal. Sci. Technol. 2016, 6, 413. (b) Yi,
H.; Bian, C.; Hu, X.; Niu, L.; Lei, A. Chem. Commun. 2015, 51,
14046. (c) Lu, Q.; Zhang, J.; Zhao, G.; Qi, Y.; Wang, H.; Lei, A. J.
Am. Chem. Soc. 2013, 135, 11481. (d) Huang, M.-H.; Zhu, Y.-L.;
Hao, W.-J.; Wang, A.-F.; Wang, D.-C.; Liu, F.; Wei, P.; Tu, S.-J.;
Jiang, B. Adv. Synth. Catal. 2017, 359, 2229.
(15) (a) Wei, W.; Ji, J.-X. Angew. Chem. Int. Ed. 2011, 50, 9097.
(b) Zhang, G.-Y.; Li, C.-K.; Li, D.-P.; Zeng, R.-S.; Shoberu, A.; Zou,
J.-P. Tetrahedron 2016, 72, 2972. (c) Wei, W.; Liu, C.; Yang, D.;
Wen, J.; You, J.; Suo, Y.; Wang, H. Chem. Commun. 2013, 49,
10239. (d) Wei, W.; Wen, J.; Yang, D.; Wu, M.; You, J.; Wang, H.
Org. Biomol. Chem. 2014, 12, 7678.
© Georg Thieme Verlag Stuttgart · New York — Synlett 2018, 29, A–F