Redox-triggered hydroarylation of o-(hydroxyalkyl)arylalkynes with arylsulfonyl chlorides using visible light catalysis

Article abstract of DOI:10.1007/s11426-015-5529-0

A new radical-mediated method for the synthesis of 1-(2-(1,2-diarylvinyl)phenyl)ethan-1-ones by the redox hydroarylation of o-(hydroxyalkyl)arylalkynes with arylsulfonyl chlorides is described. This visible light catalysis method proceeds via a sequence o

Full text of DOI:10.1007/s11426-015-5529-0

SCIENCE CHINA
Chemistry
February 2016 Vol.59 No.2: 184–189
doi: 10.1007/s11426-015-5529-0
• ARTICLES •
· SPECIAL TOPIC · Organic Photochemistry
Redox-triggered hydroarylation of o-(hydroxyalkyl)arylalkynes
with arylsulfonyl chlorides using visible light catalysis
Renjie Song1†, Jiadong Xia1†, Jiangxi Yu1,2* & Jinheng Li1*
1State Key Laboratory of Chemo/Biosensing and Chemometrics; College of Chemistry and Chemical Engineering, Hunan University,
Changsha 410082, China
2Key Laboratory of Functional Organometallic Materials of College of Hunan Province; College of Chemistry and Material Science,
Hengyang Normal University, Hengyang 421008, China
Received August 31, 2015; accepted September 14, 2015; published online December 15, 2015
A new radical-mediated method for the synthesis of 1-(2-(1,2-diarylvinyl)phenyl)ethan-1-ones by the redox hydroarylation of
o-(hydroxyalkyl)arylalkynes with arylsulfonyl chlorides is described. This visible light catalysis method proceeds via a se-
quence of the radical addition of aryl group across the CC triple bond, protonation and redox reaction, and represents a new
redox transformation reaction directed by a neighboring hydroxyl group.
hydroarylation, redox, visible light catalysis, alkynes, arylsulfonyl chlorides
Citation:
Song RJ, Xia JD, Yu JX, Li JH. Redox-triggered hydroarylation of o-(hydroxyalkyl)arylalkynes with arylsulfonyl chlorides using visible light cata-
–
lysis. Sci China Chem, 2016, 59: 184 189, doi: 10.1007/s11426-015-5529-0
The redox-triggered strategy has proven to be one of the
most important tools for the construction of complex and
useful compounds [13–15]. Maulide and co-workers [16]
have recently reported a new intramolecular redox-triggered
C–H functionalization through the reduction of the neigh-
boring carboxaldehyde group. We reason that this redox-
triggered strategy might be applicable to the alkenylation of
arenes with alkynes. Herein, we report a new redox-
triggered hydroarylation of o-(hydroxyalkyl)arylalkynes
1 Introduction
Aryl olefins are important motifs that widely found in natu-
ral products, pharmaceuticals and functional materials, and
can also serve as useful synthetic building blocks in organic
synthesis [1–6]. Accordingly, an increase in the develop-
ment of new efficient methods for the synthesis of aryl ole-
fins has been witnessed. Attractive straightforward methods
include the alkenylation of arenes with alkynes (Eq. (1) in
Scheme 1) [7–12]. However, there are still limitations with
existing transformations such as the need to use harsh reac-
tion conditions, the presence of a competitive alkyne
polymerization reactions and the moderate selectivity ob-
tained. Therefore, the development of new efficient routes,
especially selective and environmental-benign strategies, for
accessing the aryl olefins, is highly interesting.
†Contributed equally to this work
*Corresponding authors (email: hnhyyjx@126.com; jhli@hnu.edu.cn)
Scheme 1 Alkenylation of arenes with alkynes.
© Science China Press and Springer-Verlag Berlin Heidelberg 2015
chem.scichina.com link.springer.com

Song et al. Sci China Chem February (2016) Vol.59 No.2
185
with arylsulfonyl chlorides for the construction of 1-(2-(1,2-
diarylvinyl) phenyl)ethan-1-ones using visible light cataly-
sis [17–29] (Eq. (2) in Scheme 1). This method allows the
formation of aryl olefins through a sequence of the radical
addition of arylsulfonyl chlorides across a C-C triple bond,
protonation and redox reaction, and represents the first ex-
ample of hydroarylation of alkynes via a redox-triggered
visible light catalysis.
132.0, 131.1, 130.1, 129.8, 129.7, 128.1, 127.9, 127.6,
127.4, 123.4; LRMS (EI 70 eV) m/z (%): 405 (M+, 100),
328 (45), 283 (25), 105 (39); HRMS (ESI) for C27H20NO3
[M+H]+ calcd. 406.1443, found. 406.1449.
2.3.2 1-(2-(1,2-Diphenylvinyl)phenyl)ethanone (3bb)
1
Yellow oil; H NMR (500 MHz, CDCl3, major isomer) :
7.68–7.66 (m, 1H), 7.47–7.41 (m, 3H), 7.35–7.22 (m, 5H),
7.12–7.11 (m, 3H), 7.02 (s, 1H), 6.97–6.95 (m, 2H), 2.20 (s,
3H); 13C NMR (125 MHz, CDCl3) : 201.1, 142.5, 141.8,
140.3, 139.5, 137.0, 136.6, 133.6, 132.2, 131.7, 131.4,
129.4, 128.8, 128.3, 128.1, 127.7, 127.6, 127.5, 127.2,
126.9, 29.7, 28.7; LRMS (EI 70 eV) m/z (%): 298 (M+, 56),
221 (100), 178 (32); HRMS (ESI) for C22H19O [M+H]+
calcd. 299.1436, found. 299.1442.
2 Experimental
2.1 General experimental
All the materials and solvents were purchased from com-
mercial suppliers and used without purification. IR meas-
urements were performed on a FTIR Shimadzu DR-8000
(Japan) spectrometer fitted with a Pike Technologies MIRa-
2.3.3 1-(2-(2-Phenyl-1-p-tolylvinyl)phenyl)ethanone (3bc)
1
Yellow oil; Z/E=5:1; H NMR (500 MHz, CDCl3, major
1
cle Single Reflection ATR adapter. H and 13C NMR spec-
isomer) : 7.66 (d, J=7.5 Hz, 1H), 7.47–7.40 (m, 2H, major
isomer), 7.23–7.17 (m, 4H, major isomer), 7.13–7.09 (m,
5H, both isomers), 7.01 (s, 1H, major isomer), 6.94 (d,
J=7.5 Hz, 2H, major isomer), 2.33 (s, 3H, major isomer),
2.22 (s, 3H, major isomer); 13C NMR (125 MHz, CDCl3,
both isomers) : 201.3, 141.6, 140.4, 139.6, 137.5, 137.1,
136.5, 132.1, 131.7, 130.2, 129.4, 129.3, 129.1, 128.8,
128.1, 127.7, 127.6, 127.1, 126.8, 28.8, 21.1; LRMS (EI 70
ev) m/z (%): 312 (M+, 78), 235 (100), 221 (26), 119 (53);
HRMS (ESI) for C23H21O [M+H]+ calcd. 313.1592, found.
313.1598.
tra were recorded on a Bruker DRX-500 spectrometer
(Germany) (1H at 500 MHz and 13C at 125 MHz). NMR
data were obtained in CDCl3 unless otherwise noted.
High-resolution mass spectra were recorded on a Bruker
microTOF-QII (ESI) spectrometer (Germany). Preparative
thin-layer chromatography was performed on silica gel
plates with PF254 indicator. Flash column chromatography
was performed with silica gel 60N unless otherwise noted.
2.2 Typical experimental procedure for the redox-
triggered hydroarylation of o-(hydroxyalkyl)arylalky-
nes with arylsulfonyl chloride using visible light catalysis
2.3.4 1-(2-(1-(4-Acetylphenyl)-2-phenylvinyl)phenyl)eth-
anone (3bd)
A mixture of phenyl(2-(phenylethynyl)phenyl)methanol 1a
(0.2 mmol), 4-nitrobenzenesulfonyl chloride 2a (0.4 mmol),
[Ru(bpy)3Cl2]·6H2O (5 mol%), NaHCO3 (0.5 mmol), and
anhydrous MeCN (3 mL) was added to a Schlenk tube. The
mixture was stirred at 45 °C (oil bath temperature) under
nitrogen atmosphere 36 W compact fluorescent light for the
indicated time until the starting material was completely
consumed by TLC monitoring and GC-MS analysis. Upon
the completion of the reaction, diethyl ether was poured into
the mixture, filtrated and evaporated under vacuum. The res-
idue was purified by flash column chromatography (hexane/
ethyl acetate=10:1, v/v) to afford the desired product 3aa.
Yellow oil; Z/E=2.5:1; 1H NMR (500 MHz, CDCl3) : 7.88
(d, J=8.5 Hz, 2H), 7.73–7.71 (m, 1H), 7.50–7.44 (m, 2H),
7.42–7.39 (m, 1H), 7.37 (d, J=8.5 Hz, 2H), 7.25–7.22 (m,
1H), 7.13–7.12 (m, 2H), 7.09 (s, 1H), 6.96–6.94 (m, 2H),
2.58 (s, 3H), 2.19 (s, 3H); 13C NMR (125 MHz, CDCl3) :
200.5, 197.6, 149.4, 147.2, 141.1, 139.8, 139.0, 136.6,
135.8, 132.2, 132.0, 130.9, 129.9, 129.5, 129.4, 129.1,
128.6, 128.4, 128.3, 128.1, 128.0, 127.3, 127.1, 122.1,
120.5, 83.3, 29.7, 28.4, 26.6, 24.0; LRMS (EI 70 eV) m/z
(%): 340 (M+, 86), 263 (100), 221 (34), 193 (42); HRMS
(ESI) for C24H21O2 [M+H]+ calcd. 341.1542, found.
341.1548.
2.3 Characterization of compound 3
2.3.5 1-(2-(1-(4-Chlorophenyl)-2-phenylvinyl)phenyl)eth-
2.3.1 (2-(1-(4-Nitrophenyl)-2-phenylvinyl)phenyl)(phenyl)
anone (3be)
1
methanone (3aa)
Yellow oil; Z/E=2.5:1; H NMR (500 MHz, CDCl3, major
1
Yellow solid; m.p. 128.7–129.5 °C (uncorrected); H NMR
isomer) : 7.69–7.67 (m, 1H, major isomer), 7.52–7.38 (m,
3H, major isomer), 7.26–7.18 (m, 5H, major isomer),
7.12–7.10 (m, 3H, major isomer), 6.97 (s, 1H, major iso-
mer), 6.94–6.92 (m, 1H, major isomer), 2.18 (s, 3H, major
isomer); 13C NMR (125 MHz, CDCl3, both isomers) :
200.8, 141.1, 140.8, 140.0, 139.2, 136.8, 133.5, 133.4,
(500 MHz, CDCl3) : 8.08 (d, J=9.0 Hz, 2H), 7.57–7.53
(m, 1H), 7.45–7.43 (m, 4H), 7.41–7.33 (m, 4H), 7.20 (t,
J=8.0 Hz, 2H), 7.11–7.07 (m, 3H), 7.04 (s, 1H), 6.96 (d,
J=7.0 Hz, 2H); 13C NMR (125 MHz, CDCl3) : 196.3,
149.1, 146.8, 139.6, 139.4, 136.5, 136.4, 132.6, 132.3,

186
Song et al. Sci China Chem February (2016) Vol.59 No.2
132.2, 132.1, 132.0, 131.9, 130.8, 130.5, 129.4, 128.9,
128.5, 128.5, 128.4, 128.3, 128.1, 127.9, 127.8, 127.4,
127.1, 29.9, 28.5; LRMS (EI 70 eV) m/z (%): 334 (M++2,
23), 332 (M+, 66), 255 (100), 221 (32); HRMS (ESI) for
C22H18ClO [M+H]+ calcd. 333.1046, found. 333.1052.
isomer), 2.21 (s, 3H, major isomer); 13C NMR (125 MHz,
CDCl3, both isomers) : 202.6, 200.0, 149.3, 147.1, 146.7,
142.1, 140.7, 139.4, 139.0, 138.7, 137.9, 137.8, 133.4 (2),
133.3, 132.3 (2), 131.6, 131.1 (2), 130.9, 129.6, 129.4,
129.4, 129.1, 129.0, 128.4, 128.3, 128.0, 127.4, 123.6,
123.4, 29.6, 28.3, 21.2 (2); LRMS (EI 70 eV) m/z (%): 357
(M+, 83), 266 (100), 221 (54), 193 (48); HRMS (ESI) for
C23H20NO3 [M+H]+ calcd. 358.1443, found. 358.1449.
2.3.6
1-(2-(1-(4-Iodophenyl)-2-phenylvinyl)phenyl)etha-
none (3bf)
1
Yellow oil; Z/E=15:1; H NMR (500 MHz, CDCl3, major
isomer) : 7.69–7.67 (m, 1H), 7.62–7.60 (m, 2H), 7.46–
7.41 (m, 2H), 7.21–7.19 (m, 1H), 7.11–7.10 (m, 3H),
7.03–7.01 (m, 3H), 6.98 (s, 1H), 6.93–6.01 (m, 2H), 2.18 (s,
3H); 13C NMR (125 MHz, CDCl3, major isomer) : 200.6,
142.2, 141.0, 140.0, 139.0, 137.4, 136.7, 132.2, 131.9,
129.4, 128.9, 128.5, 128.1, 127.9, 127.1, 93.2, 29.7, 28.5;
LRMS (EI 70 eV) m/z (%): 426 (M++2, 21), 424 (63), 346
(100), 211 (46); HRMS (ESI) for C22H18IO [M+H]+ calcd.
425.0402, found. 405.0408.
2.3.10
phenyl)ethanone (3ea)
1-(2-(2-(4-Fluorophenyl)-1-(4-nitrophenyl)vinyl)
1
Yellow oil; Z/E=3.75:1; H NMR (500 MHz, CDCl3) :
8.15–8.13 (m, 2H, major isomer), 8.07 (d, J=9.0 Hz, 2H,
minor isomer), 7.79–7.78 (m, 1H, major isomer), 7.53–7.50
(m, 4H, both isomers), 7.42–7.39 (m, 2H, major isomer),
7.31 (d, J=8.5 Hz, 2H, minor isomer), 7.21–7.19 (m, 1H,
major isomer), 7.04 (s, 1H, major isomer), 6.92–6.89 (m,
4H, both isomers), 6.82 (t, J=8.5 Hz, 2H, major isomer),
6.69 (s, 1H, minor isomer), 2.35 (s, 3H, minor isomer), 2.23
(s, 3H, major isomer); 13C NMR (125 MHz, CDCl3, both
isomers) : 199.8, 162.9, 160.9, 149.0, 146.8, 140.4, 139.1,
138.4, 132.5 (3), 132.3, 131.6, 131.5, 131.3, 131.2, 131.1
(2), 129.7, 129.6, 128.5, 128.2, 127.5, 123.6, 123.4, 115.6,
115.4, 115.3, 115.2, 29.5, 28.2; LRMS (EI 70 eV) m/z (%):
363 (M++2, 8), 361 (M+, 72), 266 (100), 239 (45); HRMS
(ESI) for C22H17FNO3 [M+H]+ calcd. 362.1193, found.
362.1199.
2.3.7
1-(2-(2-Phenyl-1-(thiophen-2-yl)vinyl)phenyl)etha-
none (3bg)
1
Yellow oil; Z/E>20:1; H NMR (500 MHz, CDCl3, major
isomer) : 7.74 (d, J=7.5 Hz, 1H), 7.51–7.45 (m, 2H),
7.30–7.29 (m, 1H), 7.20–7.19 (m, 1H), 7.11–7.09 (m, 4H),
6.93–6.89 (m, 3H), 6.61–6.60 (m, 1H), 2.33 (s, 3H); 13C
NMR (125 MHz, CDCl3, major isomer) : 201.0, 147.3,
140.0, 138.4, 136.2, 135.5, 132.0, 131.5, 129.2, 129.0,
128.3, 128.2, 127.5, 127.1, 126.8, 125.9, 124.9, 28.9;
LRMS (EI 70 eV) m/z (%): 304 (M+, 100), 271 (19), 261
(29), 227 (86), 193 (42); HRMS (ESI) for C20H17OS
[M+H]+ calcd. 305.1000, found. 305.1006.
2.3.11 1-(2-(3,3-Dimethyl-1-(4-nitrophenyl)but-1-enyl)phe-
nyl)ethanone (3fa)
1
Yellow oil; Z/E=7:1; H NMR (500 MHz, CDCl3, major
isomer) : 8.17 (d, J=9.0 Hz, 2H), 7.52 (d, J=8.5 Hz, 2H),
7.47–7.45 (m, 1H), 7.35–7.28 (m, 2H), 7.09 (d, J=7.5 Hz,
1H), 5.66 (s, 1H), 2.49 (s, 3H), 0.97 (s, 9H); 13C NMR (125
MHz, CDCl3, major isomer) : 203.3, 147.8, 146.9, 144.8,
142.6, 140.6, 136.1, 131.2, 130.5, 130.2, 127.6, 127.1,
122.8, 34.4, 30.9, 30.3; LRMS (EI 70 eV) m/z (%): 323
(M+, 5), 266 (100), 219 (21), 178 (8); HRMS (ESI) for
C20H22NO3 [M+H]+ calcd. 324.1600, found. 324.1606.
2.3.8
1-(2-(2-(4-Methoxyphenyl)-1-(4-nitrophenyl)vinyl)
phenyl)ethanone (3ca)
1
Yellow oil; Z/E=8.6:1; H NMR (500 MHz, CDCl3, major
isomer) : 8.15–8.12 (m, 2H), 7.79–7.77 (m, 1H), 7.55–
7.48 (m, 2H), 7.40 (d, J=7.0 Hz, 2H), 7.25–7.23 (m, 1H),
7.06 (s, 1H), 6.88–6.86 (m, 2H), 6.69–6.67 (m, 2H), 3.75 (s,
3H), 2.22 (s, 3H); 13C NMR (125 MHz, CDCl3, major iso-
mer) : 200.1, 159.1, 149.4, 146.5, 139.4, 138.8, 138.1,
132.4, 132.3, 131.1, 130.8, 129.4, 128.9, 128.3, 127.3,
123.6, 113.7, 55.2, 28.4; LRMS (EI 70 eV) m/z (%): 373
(M+, 83), 266 (100), 221 (45), 178 (18); HRMS (ESI) for
C23H20NO4 [M+H]+ calcd. 374.1392, found. 374.1398.
2.3.12 (2-(1-(4-Nitrophenyl)-2-phenylvinyl)phenyl)(p-tolyl)
methanone (3ga)
Yellow oil; Z/E=2.3:1; 1H NMR (500 MHz, CDCl3) : 8.06
(d, J=7.5 Hz, 2H, major isomer), 7.86 (d, J=8.5 Hz, 2H,
minor isomer), 7.53–7.35 (m, 9H, both isomers), 7.26 (d,
J=8.0 Hz, 1H, major isomer), 7.14–7.06 (m, 6H, both iso-
mers), 7.04 (s, 1H, major isomer), 7.01–6.97 (m, 4H, both
isomers), 6.87 (d, J=6.5 Hz, 1H, major isomer), 6.82 (s, 1H,
minor isomer), 2.35 (s, 3H, minor isomer), 2.32 (s, 3H, ma-
jor isomer). 13C NMR (125 MHz, CDCl3, both isomers) :
197.5, 196.1, 149.1, 146.6 (2), 144.2, 143.5, 142.3, 139.8,
139.6, 139.3, 136.4, 136.2, 134.0, 133.7, 132.2, 132.0,
131.8, 131.0, 130.6, 130.1, 130.0 (2), 129.7, 129.3, 128.8,
128.6, 128.2, 128.1 (2), 127.6 (2), 127.5, 127.3, 123.4,
2.3.9 1-(2-(1-(4-Nitrophenyl)-2-p-tolylvinyl)phenyl)etha-
none (3da)
Yellow oil; Z/E=1.1:1; 1H NMR (500 MHz, CDCl3) : 8.14
(d, J=9.0 Hz, 2H, major isomer), 8.08 (d, J=8.5 Hz, 2H,
minor isomer), 7.77 (d, J=7.5 Hz, 2H, major isomer), 7.59–
7.22 (m, 11H, both isomers), 7.07 (s, 1H, major isomer),
7.01–6.94 (m, 6H, both isomers), 6.82 (d, J=7.5 Hz, 2H,
major isomer), 6.71 (s, 1H, minor isomer), 2.36 (s, 3H, mi-
nor isomer), 2.30 (s, 3H, minor isomer), 2.26 (s, 3H, major

Song et al. Sci China Chem February (2016) Vol.59 No.2
187
123.1, 21.6 (2) ; LRMS (EI 70 eV) m/z (%): 419 (M+, 100),
342 (52), 297 (21), 252 (29), 119 (27); HRMS (ESI) for
C28H22NO3 [M+H]+ calcd. 420.1600, found. 420.1606.
isomer) : 7.75–7.67 (m, 1H), 7.52–7.45 (m, 2H), 7.30–7.29
(m, 1H), 7.17–7.16 (m, 1H), 7.04 (s, 1H), 6.89–6.84 (m,
3H), 6.66 (d, J=9.0 Hz, 2H), 6.56–6.55 (m, 1H), 3.72 (s,
3H), 2.34 (s, 3H); 13C NMR (125 MHz, CDCl3, major iso-
mer) : 201.2, 158.6, 147.6, 140.1, 138.6, 133.4, 132.1,
131.5, 130.5, 129.1, 128.8, 128.2, 127.5, 126.5, 125.4,
124.4, 113.7, 55.1, 29.0; LRMS (EI 70 eV) m/z (%): 334
(M+, 100), 291 (16), 227 (76); HRMS (ESI) for C21H19O2S
[M+H]+ calcd. 335.1106, found. 335.1112.
2.3.13
(4-Fluorophenyl)(2-(1-(4-nitrophenyl)-2-phenyl-
vinyl)phenyl)methanone (3ha)
Yellow oil; Z/E=1.3:1; 1H NMR (500 MHz, CDCl3) : 8.10
(d, J=9.0 Hz, 2H, major isomer), 7.90 (d, J=8.5 Hz, 2H,
minor isomer), 7.64–7.33 (m, 14H, both isomers),
7.14–6.98 (m, 10H, both isomers), 6.91 (d, J=7.5 Hz, 2H,
major isomer), 6.87–6.84 (m, 4H, both isomers), 6.81 (s,
1H, minor isomer); 13C NMR (125 MHz, CDCl3, both iso-
mers) : 196.3, 194.8, 166.4, 164.3, 149.0, 146.8, 146.7,
146.5, 142.3, 139.5, 139.4 (2), 139.2 (2), 136.3, 136.0,
134.0, 133.6, 132.7, 132.5, 132.4, 132.4, 132.3, 131.9,
131.7, 131.2, 130.7, 130.5, 129.7, 129.6, 129.2, 128.9,
128.3, 128.2, 127.8, 127.7, 127.6, 127.4, 123.4, 123.2,
115.4, 115.2 (2) , 115.0; LRMS (EI 70 eV) m/z (%): 425
(M++2, 15), 423 (M+, 83), 346 (100), 301 (26), 119 (35);
HRMS (ESI) for C27H19FNO3 [M+H]+ calcd. 424.1349,
found. 424.1355.
3 Results and discussion
3.1 Screening of the reaction conditions
As shown in Table 1, the reaction of phenyl(2-(phenyleth-
ynyl)phenyl)methanol (1a) with 4-nitrobenzenesulfonyl
chloride (2a) was chosen as a model for reaction condition
optimization. Initially, treatment of o-(hydroxyalkyl)arylal-
kyne 1a with 4-nitrobenzenesulfonyl chloride 2a, [Ru(bpy)3-
Cl2]·6H2O, NaHCO3 and 5 W blue LED light in acetonitrile
afforded the desired product 3aa in 36% yield (Entry 1).
The identical results were achieved when using 23 W com-
pact fluorescent light (Entry 2). Interestingly, the yield of
3aa dramatically increased to 80% when using 36 W com-
pact fluorescent light (Entry 3). However, no desired reac-
tion was observed in the absence of either visible-light or
photoredox catalysts (Entry 4). Inspired by the results, a
series of other bases, including KHCO3, Na2CO3, NaOAc
and Et3N were subsequently tested, but they were less ef-
fective than NaHCO3 (Entry 3 vs. Entries 5–8). It was noted
that the reaction could be performed in the absence of bases,
albeit with a decreased yield (Entry 9). Several solvents,
such as toluene, CH2Cl2, THF and DMF, were investigated:
the results showed that their reactivity was lower than that
of MeCN (Entries 10–13). Extensive screening revealed that
the amount of [Ru(bpy)3Cl2]·6H2O affected the reaction
(Entries 14 and 15): while the use of 10 mol% [Ru(bpy)3-
Cl2]·6H2O gave the identical yield to that of 5 mol% of
[Ru(bpy)3Cl2]·6H2O; using a lower amount of [Ru(bpy)3-
Cl2]·6H2O (2 mol%) sharply decreased the yield to 28%.
Two other visible light photoredox catalysts, [Ir(ppy)3] and
Eosin Y, were also found to have high activity for the reac-
tion (Entries 16 and 17). Among the temperature examined,
45 °C was proved to be the best choice (Entries 3, 18 and
19).
2.3.14 (4-Methyl-2-(1-(4-nitrophenyl)-2-phenylvinyl)phe-
nyl)(phenyl)methanone (3ia)
Yellow oil; Z/E=1.5:1; 1H NMR (500 MHz, CDCl3) : 8.10
(d, J=9.0 Hz, 2H, major isomer), 7.88 (d, J=9.0 Hz, 2H,
minor isomer), 7.59 (d, J=7.0 Hz, 2H, minor isomer), 7.45
(d, J=6.5 Hz, 2H, major isomer), 7.41–7.05 (m, 19H, both
isomers), 7.02 (s, 1H, major isomer), 6.95 (d, J=7.0 Hz, 2H,
major isomer), 6.83 (d, J=7.0 Hz, 2H, minor isomer), 6.80
(s, 1H, minor isomer), 2.42 (s, 3H, minor isomer), 2.41 (s,
3H, major isomer); (s, 3H); 13C NMR (125 MHz, CDCl3,
both isomers) : 198.0, 196.3, 149.2, 146.6, 146.5, 142.6,
141.8, 140.7, 139.7, 139.6, 137.5, 136.9, 136.8, 136.5,
136.4, 136.2, 133.7, 132.9, 132.7, 132.4, 131.7, 131.6,
131.3, 130.5, 129.8, 129.7, 129.6, 129.3 (2) , 128.4, 128.1
(3), 128.0 (2), 127.8, 127.6, 127.5, 123.4, 123.1, 21.5, 21.4;
LRMS (EI 70 eV) m/z (%): 419 (M+, 100), 342 (46), 297
(21), 105 (35); HRMS (ESI) for C28H22NO3 [M+H]+ calcd.
420.1600, found. 420.1606.
2.3.15 1-(2-(2-(4-Methoxyphenyl)-1-phenylvinyl)phenyl)
ethanone (3cb)
1
Yellow oil; Z/E>20:1; H NMR (500 MHz, CDCl3, major
isomer) : 7.69–7.67 (m, 1H), 7.48–7.41 (m, 2H), 7.29–7.23
(m, 6H), 6.98 (s, 1H), 6.89 (d, J=7.0 Hz, 2H), 6.67–6.66 (m,
2H), 3.73 (s, 3H), 2.23 (s, 3H); 13C NMR (125 MHz,
CDCl3, major isomer) : 201.4, 158.5, 142.6, 140.4, 139.7,
132.2, 131.8, 130.7, 129.7, 128.8, 128.3, 128.0, 127.7,
127.3, 127.0, 113.6, 55.1, 28.9; LRMS (EI 70 eV) m/z (%):
328 (M+, 82), 251 (24), 221 (100), 119 (48); HRMS (ESI)
for C23H21O2 [M+H]+ calcd. 329.1542, found. 329.1548.
3.2 Screening of the arylsulfonyl chlorides
With the optimal conditions in hand, a variety of aryl-
sulfonyl chlorides 2 were first probed in the presence of
alkyne 1b, [Ru(bpy)3Cl2]·6H2O, NaHCO3 and 36 W com-
pact fluorescent light (Scheme 2). We were pleased to find
that benzenesulfonyl chloride 2b was viable to furnish
product 3bb in moderate yield. Arylsulfonyl chlorides 2,
2.3.16 1-(2-(2-(4-Methoxyphenyl)-1-(thiophen-2-yl)vinyl)
phenyl)ethanone (3cg)
1
Yellow oil; Z/E>99:1; H NMR (500 MHz, CDCl3, major

188
Song et al. Sci China Chem February (2016) Vol.59 No.2
Table 1 Screening of the reaction conditions a)
Entry
[M] (mol%)
Base (equiv.) Solvent T (°C) Yield (%) b)
1 c) [Ru(bpy)3Cl2] (5) NaHCO3 (2.5) MeCN
2 d) [Ru(bpy)3Cl2] (5) NaHCO3 (2.5) MeCN
45
45
45
45
45
45
45
45
45
45
45
45
45
45
45
45
45
30
60
36
37
80
0
3
4
[Ru(bpy)3Cl2] (5) NaHCO3 (2.5) MeCN
NaHCO3 (2.5) MeCN
-
5
[Ru(bpy)3Cl2] (5) KHCO3 (2.5) MeCN
[Ru(bpy)3Cl2] (5) Na2CO3 (2.5) MeCN
[Ru(bpy)3Cl2] (5) NaOAc (2.5) MeCN
27
56
21
12
19
5
6
7
8
[Ru(bpy)3Cl2] (5)
[Ru(bpy)3Cl2] (5)
Et3N (2.5)
MeCN
MeCN
Scheme 2 Screening of the arylsulfonyl chlorides 2. Reaction conditions:
1b (0.2 mmol), 2 (2 equiv.), [Ru(bpy)Cl2]·6H2O (5 mol%), NaHCO3 (2.5
equiv.) and MeCN (anhydrous, 2 mL) with 36 W compact fluorescent light
9
-
10
11
12
13
14
15
16
17
18
19
[Ru(bpy)3Cl2] (5) NaHCO3 (2.5) toluene
[Ru(bpy)3Cl2] (5) NaHCO3 (2.5) CH2Cl2
[Ru(bpy)3Cl2] (5) NaHCO3 (2.5) THF
[Ru(bpy)3Cl2] (5) NaHCO3 (2.5) DMF
[Ru(bpy)3Cl2] (2) NaHCO3 (2.5) MeCN
[Ru(bpy)3Cl2] (10) NaHCO3 (2.5) MeCN
1
for 24 h. The Z/E ratio is given in parenthesis which is determined by H
8
NMR analysis.
40
trace
28
77
78
53
60
76
[Ir(ppy)3] (5)
Eosin Y (5)
NaHCO3 (2.5) MeCN
NaHCO3 (2.5) MeCN
[Ru(bpy)3Cl2] (5) NaHCO3 (2.5) MeCN
[Ru(bpy)3Cl2] (5) NaHCO3 (2.5) MeCN
a) Reaction conditions: 1a (0.2 mmol), 2a (2 equiv.), [M], base and
solvent (anhydrous, 2 mL) with 36 W compact fluorescent light for 24 h; b)
yield of the isolated product; c) 5 W blue LED light used instead of 36 W
compact fluorescent light; d) 23 W compact fluorescent light used instead
of 36 W compact fluorescent light.
bearing either electron-donating (Me) or electron-with-
drawing substituents, (Ac, Cl and I) at the 4-position of the
aromatic ring, were compatible with the optimal conditions
(Products 3bc–3bf). For example, p-Me-substituted aryl-
sulfonyl chloride delivered product 3bc in 41% yield. Using
p-Ac-substituted arylsulfonyl chloride, the desired product
3bd was also formed in 61% yield. Notably, halogen atoms,
Cl and I, could be well-tolerated, thereby facilitating addi-
tional modifications at the halogenated position (Products
3be–3bf). Interestingly, thiophene-2-sulfonyl chloride 2g, a
heteroarene, was also a suitable substrate for the reaction
(Product 3bg).
Scheme 3 Redox hydroarylation of o-(hydroxyalkyl)arylalkynes 1 with
arylsulfonyl chlorides 2a. Reaction conditions: 1 (0.2 mmol), 2 (2 equiv.),
[Ru(bpy)3Cl2]·6H2O (5 mol%), NaHCO3 (2.5 equiv.) and MeCN (anhy-
drous, 2 mL) with 36 W compact fluorescent light for 24 h. The Z/E ratio
determined by 1H NMR analysis is given in parenthesis.
aliphatic alkyne 1f also underwent the redox-triggered hy-
droarylation reaction, giving product 3fa in good yield. This
protocol was applicable to Me- or F-substituted alcohols
1g–1i, assembling 3ga–3ia in 60%–67% yields. Gratifying-
ly, the reaction of 1-(2-((4-methoxyphenyl)ethynyl) phe-
nyl)ethan-1-ol 1c with arylsulfonyl chlorides 2b or 2g also
delivered 3cb and 3cg in 48% and 71% yields, respectively.
3.3 Screening of the o-(hydroxyalkyl)arylalkynes
We next explored the feasibility of this redox-triggered hy-
droarylation protocol with respect to internal arylalkynes 1
(Scheme 3). In the presence of 2a, [Ru(bpy)3Cl2]·6H2O,
NaHCO3 and 36 W compact fluorescent light, a number of
internal diarylalkynes 1c–1e, having either electron-with-
drawing or electron-donating groups, were smoothly con-
verted into 3ca–3ea in 45%–78% yields. For example, 1-
(2-((4-methoxyphenyl)ethynyl)phenyl)ethan-1-ol 1c reacted
with 2a afforded the desired product 3ca in 78% yield. In
the case of substrate 1e with an electron-withdrawing group,
the reaction constructed product 3ea in 45% yield. Notably,
4 Conclusions
In summary, we have developed the first redox-triggered
hydroarylation of o-(hydroxyalkyl)arylalkynes with aryl-

Song et al. Sci China Chem February (2016) Vol.59 No.2
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Acknowledgments This work was supported by the National Natural
Science Foundation of China (21402046, 21172060, 21472039), and the
Fundamental Research Funds for the Central Universities. Dr. Renjie Song
also thanks the Fundamental Research Funds for the Central Universities.
Conflict of interest The authors declare that they have no conflict of
interest.
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