External oxidant-free cross-coupling of arylcopper and alkynylcopper reagents leading to arylalkyne

Article abstract of DOI:10.1039/c7ra03348f

External oxidant-free oxidative cross-coupling between arylcopper and alkynylcopper has been performed, which provides a new way for the formation of arylalkyne with high selectivity.

Full text of DOI:10.1039/c7ra03348f

RSC Advances
View Article Online
View Journal | View Issue
PAPER
External oxidant-free cross-coupling of arylcopper
and alkynylcopper reagents leading to arylalkyne†
Cite this: RSC Adv., 2017, 7, 28308
ab
Sheng Wang,a Yaosen Min,a Xiaowei Zhanga and Chanjuan Xi
*
Received 22nd March 2017
Accepted 22nd May 2017
External oxidant-free oxidative cross-coupling between arylcopper and alkynylcopper has been performed,
which provides a new way for the formation of arylalkyne with high selectivity.
DOI: 10.1039/c7ra03348f
rsc.li/rsc-advances
Results and discussion
Introduction
Initially, we used phenylcopper 2a generated from phenyl
magnesium 1a with CuCl$2LiCl salts6 and (phenylethynyl)
copper 3a as starting materials. Reaction of 2a and 3a in the
THF solvent at room temperature for 12 h afforded 4aa in 5%
yield (Table 1, entry 1). During the reaction, we noticed the
reaction mixture was a slurry. Therefore, we tried to add some
additives such as hexamethyl-phosphoramide (HMPA), tetra-
Arylalkynes are useful building blocks in organic synthesis as
well as basic functional groups in various bioactive compounds
and natural products.1 The most common approach to ary-
lalkynes is transition-metal-catalyzed cross-coupling reaction
such as Sonogashira reaction2 or Stille reaction3 between aryl-
halides and terminal alkynes or alkynyltin compounds.
Recently, the oxidative cross-coupling reaction has been
considered as a convenient method to synthesize arylalkynes
under mild conditions utilizing various transition metals as
catalysts in the presence of oxidants.4 Although this reaction
provides a straightforward strategy for the synthesis of the
unsymmetrical alkynes, realizing oxidative cross-coupling
between arylmetal and alkylmetal in high efficiency with
oxidants is still difficult since potential side reactions such as
homo-coupling of the arylmetals or the alkylmetals as well as
direct reaction between organometallic reagents and oxidants.
During the course of our study on the carbon–carbon bond
formation utilizing alkynylcoppers,5 we found a direct cross-
coupling of alkynylcopper and arylcopper reagents to afford
arylalkynes with excellent selectivity without external oxidant,
which possibly underwent disproportionation mechanism and
was worthy of investigation (Scheme 1).
methylethylenediamine
(TMEDA),
1,8-diazabicyclo[5.4.0]-
undec-7-ene (DBU), 4-dimethylaminopyridine (DMAP) and
pyridine, respectively in the vessel to improve the solubility of
Table 1 Initial optimization studiesa
Entry
Temp (ꢀC)
Additive
Yield [%] of 4aab
1
rt
—
5
2
3
4
5
6
7
8
9
rt
rt
rt
rt
HMPA
TMEDA
DBU
Trace
Trace
Trace
Trace
18
85 (75)
72
70
DMAP
rt
Pyridine
Pyridine
Pyridine
Pyridine
Pyridine/DDQ
Pyridine/DCE
Pyridine/DBE
50
67
80
50
50
50
10c
11c
12c
Trace
9
6
Scheme 1 Direct coupling reaction of organocoppers.
a
aKey Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Ministry of
Education, Department of Chemistry, Tsinghua University, Beijing 100084, China.
E-mail: cjxi@tsinghua.edu.cn
Reaction conditions: phenylcopper 2a prepared in situ from the
corresponding phenylmagnesium bromide 1a (0.50 mmol, 1.0 M in
THF, 1.0 mL) with the 0.6 mL 1 M CuCl$2LiCl in THF-solution;
b
(phenylethynyl)copper 3a (0.5 mmol, 82 mg), N2, 12 h. GC yield,
bState Key Laboratory of Elemento-Organic Chemistry, Nankai University, Tianjin
yield based on n-dodecane, isolated yield was given in parenthesis.
300071, China
c
Diphenyl was obtained around in 60% GC yield.
† Electronic supplementary information (ESI) available: 1H NMR and 13C NMR
spectra for all compounds. See DOI: 10.1039/c7ra03348f
28308 | RSC Adv., 2017, 7, 28308–28312
This journal is © The Royal Society of Chemistry 2017

View Article Online
Paper
RSC Advances
Table
2
Coupling of arylcopper 2ba with various alkynylcopper Table
3
Oxidative coupling of various arylcopper 2a with alky-
reagents
nylcopper reagent 3
Entry Alkynylcopper reagent Alkyne
Yieldb (%)
73
1
2
Entry
1
Grignard reagent
Alkyne
Yieldb (%)
62
72
66
3
2
3
70
78
4
5
63
75
6
7
66
58
4
5
45
44
8
42
a
The (3-methoxyphenyl)copper 2b was prepared in situ from (3-
methoxyphenyl)magnesium bromide 1a (0.50 mmol, 1.0 M in THF,
b
1.0 mL) with the 0.6 mL 1 M CuCl$2LiCl in THF-solution. Isolated
yields.
6
35
organometallic reagents (entries 2–6). Only pyridine was found
to enhance the yield to 18% (entry 6). The reaction was screened
in different temperature (entries 6–9) and we found that when
the reaction was treated at 50 ꢀC, the product 4aa was formed in
75% isolated yield (entry 7). In the above reactions, the homo-
coupling products have not been obtained and copper mirror
on the wall of the reaction vessel was observed.
Theoretically, oxidative coupling of two organometallic
reagents forming C–C bond, the oxidants are denitely neces-
sary to take away two redundant electrons from organometal-
lics. Therefore, dichloroethane (DCE), 2,3-dichloro-5,6-
dicyanobenzoquinone (DDQ) and dibromoethane (DBE) were
examined as the oxidants under the same reaction conditions.
In each case, trace product 4aa and homo-coupling product
diphenyl was detected in GC-MS (entries 10–12). Compared with
oxidative cross-coupling reaction in the presence of external
oxidant, our reaction may take place through an intermolecular
disproportionation of arylcopper and alkynylcopper. The
formation of copper mirror on the wall of the reaction vessel
further conrmed the intermolecular disproportionation.
a
The arylcopper reagent 2 was prepared in situ from the corresponding
arylmagnesium halide 1 (0.50 mmol) with the CuCl$2LiCl in THF-
solution. b Isolated yields.
Under the optimized conditions, the experiments about
functional-group compatibility were carried out. Firstly, aryl
substituted alkynylcoppers 3 including phenyl, 4-chlorophenyl,
4-uorophenyl, 4-methylphenyl, and thiophen-3-yl groups were
used to react with (3-methoxyphenyl)copper 2b and a range of
alkynes 4 were obtained in good yields (entries 1–5). Then, we
tried (cyclohex-1-en-1-ylethynyl)copper 3f and desired product
4bf was obtained in 66% yield. Furthermore, employment of
hex-1-yn-1-ylcopper 3g and (5-chloropent-1-yn-1-yl)copper 3h
also afforded product 4bg and 4bh in 58% and 42% yields,
respectively.
To establish the full scope of the reaction, compatibility of
various arylcoppers in cross coupling reaction was studied. The
This journal is © The Royal Society of Chemistry 2017
RSC Adv., 2017, 7, 28308–28312 | 28309

View Article Online
RSC Advances
Paper
copper of the arylcopper 2 to form intermediate 5, which
undergoes disproportionation reaction leading to intermediate
6 and formation of copper powder. Finally, reductive elimina-
tion yields the desired cross-coupling product 4 with concomi-
tant precipitation of another molecular copper powder from the
reaction mixture.
Conclusions
Scheme 2 Use of PhMgCl prepared by I/Mg exchange with iPrMgCl.
We have reported a new oxidative coupling of the arylcopper
and alkynylcopper, which provides a complementary way for
formation of arylalkyne. It is the rst procedure for oxidative
cross-coupling of two different organocopper reagents without
external oxidant.
Scheme 3 Cross-coupling between alkylcopper and alkynylcopper.
Experimental section
General procedure for preparation of alkynylcopper reagents
Alkynylcopper reagents were prepared according to literature
reported.8 To round-bottom ask equipped with a magnetic
stirrer were added CuSO4$5H2O (2.5 g, 10 mmol), 100 mL H2O,
10 mL 28% aqueous ammonia and 1.4 g NH2OH$HCl (1.4 g, 20
mmol), and the solution was cooled to 0 ꢀC. Then terminal
alkyne (10 mmol) dissolved in 60 mL EtOH was added. Yellow
precipitation appeared immediately and the mixture was stirred
vigorously for 5 min, followed by ltration. The solid was
washed with H2O (15 mL ꢂ 2), EtOH (15 mL ꢂ 2) and Et2O (15
mL ꢂ 3) and dried in vacuum.
Scheme 4 Plausible reaction mechanism.
representative results are summarized in Table 3. The reaction
generally lead to satisfactory yields with electron-rich arylcop-
pers (entries 1–3). While arylcoppers bearing electron-poor
groups such as Cl, CO2Me, and CN afforded the correspond-
ing alkyne in diminished yields (entries 4–6) as well as forma-
tion of undesired self-coupling product from arylcoppers.
Notably, the reaction seemed no sensitive to steric hindrance
and the results as shown in Table 2 (entry 1) and Table 3 (entries
2–3).
Arylmagnesium reagents are sensitive, which can be gener-
ated from aryl halides in situ. From practical point of view, aryl
halides could be converted into the corresponding arylmagne-
sium reagents (1f, 1h, 1i, and 1j) by iodine/magnesium
exchange from iodoarenes and iPrMgCl$LiCl.7 It was then
transmetallated with CuCl$2LiCl (in THF solution) to give the
corresponding arylcopper reagents, which was treated subse-
quently with the compound 3a to generate the alkyne (4fa, 4ha,
4ia, and 4ja) (Scheme 2), respectively.
We also tried to use alkylcopper reagents in the reaction. As
an example, reaction of cyclohexylcopper with alkynylcopper in
the presence of pyridine at ꢁ20 ꢀC for 6 h and product 4ka was
isolated in 44% (Scheme 3) as well as bicyclohexane was
detected in GC-MS.
Based on the above results, a possible mechanism for the
oxidative cross-coupling of an arylmagnesium and an alky-
nylcopper is proposed in Scheme 4. First, transmetallation of
arylmagnesium compound 1 with CuCl yields arylcopper 2. An
alkynylcopper 30 in the presence of pyridine coordinates to the
Preparation of CuCl$2LiCl (1 M in THF)
1 M CuCl$2LiCl solution was prepared according to literature
reported.6 To nitrogen-ushed 50 mL Schlenk-tube containing
a magnetic stirrer was added LiCl (0.95 g, 20 mmol) and was
heated to 130 ꢀC for 1 h in high vaccum. Then Schlenk-tube was
cooled to room temperature and charged with CuCl (0.98 g,
10 mmol, 99.999% metal basis) under nitrogen ow. The
Schlenk-tube was heated to 130 ꢀC for 5 h in high vaccum. Aer
cooling to room temperature, 10 mL fresh-distilled THF was
added and the mixture was stirred vigorously overnight under
nitrogen atmosphere protecting from light with aluminium foil.
Colorless solution was obtained and stored away from light.
Typical procedure to generate arylcopper reagents
Procedure 1. Nitrogen-ushed Schlenk-tube equipped with
a magnetic stirrer was charged with Grignard reagents (0.5
mmol). 2 mL Fresh-distilled THF was added. Then, the mixture
was cooled to ꢁ42 ꢀC and charged with 0.6 mL CuCl$2LiCl (1 M
in THF, 0.6 mmol). Aer 0.5 h, arylcopper reagents were
obtained.
Procedure 2. Nitrogen-ushed Schlenk-tube equipped with
a magnetic stirrer was charged with aryliodide (0.5 mmol). 2 mL
fresh-distilled THF was added and the solution was cooled to
0 ꢀC. 0.5 mL iPrMgCl$LiCl (1.2 M in THF, 0.6 mmol) was added
dropwise. The solution was stirred vigorously for 0.5 h. Then the
mixture was cooled to ꢁ42 ꢀC and charged with 0.6 mL
28310 | RSC Adv., 2017, 7, 28308–28312
This journal is © The Royal Society of Chemistry 2017

View Article Online
Paper
RSC Advances
CuCl$2LiCl (1 M in THF, 0.6 mmol). Aer 0.5 h, arylcopper 5.4, 3.3 Hz, 4H). 13C NMR (101 MHz, CDCl3-d) d 159.4, 135.5,
reagents were obtained.
129.4, 124.9, 124.1, 120.8, 116.3, 114.6, 91.2, 86.8, 55.3, 29.3,
25.9, 22.5, 21.6. GC-MS: 212.
1-(Hex-1-yn-1-yl)-3-methoxybenzene12 (4bg). 55 mg, 58%
General procedure of cross coupling between arylcopper
reagents and alkynylcopper reagents
1
ꢀ
yield, yellow solid, mp: 48–50 C. H NMR (400 MHz, CDCl3-d)
d 7.18 (t, J ¼ 7.9 Hz, 1H), 6.99 (d, J ¼ 7.6 Hz, 1H), 6.94–6.91 (m,
To a solution of arylcopper reagents (0.5 mmol) was added 1H), 6.84–6.80 (m, 1H), 3.79 (s, 3H), 2.40 (t, J ¼ 7.0 Hz, 2H), 1.63–
alkynylcopper reagents (0.6 mmol). 2 mL pyridine (extra dry) 1.55 (m, 2H), 1.53–1.43 (m, 2H), 0.95 (t, J ¼ 7.2 Hz, 3H). 13C NMR
was added and the mixture was heated to 50 ꢀC for 12 h. To (101 MHz, CDCl3-d) d 159.2, 129.2, 125.1, 124.1, 116.4, 114.1,
quench the reaction, 5 mL HCl (1 M) was added, extracted with 90.3, 80.4, 55.2, 30.8, 22.0, 19.1, 13.6. GC-MS: 188.
EtOAc (5 mL ꢂ 3). The combined organic layer was washed with
1-(5-Chlorohex-1-yn-1-yl)-3-methoxybenzene (4bh). 44 mg,
saturated NaCl solution, dried by Na2SO4, evaporated and 42% yield, yellow oil. 1H NMR (400 MHz, CDCl3-d) d 7.19 (t, J ¼
puried by ash chromatography.
7.9 Hz, 1H), 7.01–6.97 (m, 1H), 6.94–6.90 (m, 1H), 6.86–6.82 (m,
1,2-Diphenylethyne9 (4aa). 67 mg, 75% yield, white solid, 1H), 3.79 (s, 3H), 3.71 (t, J ¼ 6.4 Hz, 2H), 2.60 (t, J ¼ 6.8 Hz, 2H),
mp: 60–62 ꢀC. 1H NMR (400 MHz, CDCl3-d) d 7.59–7.54 (m, 4H), 2.06 (p, J ¼ 6.7 Hz, 2H). 13C NMR (101 MHz, CDCl3-d) d 159.4,
7.40–7.34 (m, 6H). 13C NMR (101 MHz, CDCl3-d) d 131.7, 128.5, 129.4, 124.7, 124.3, 116.6, 114.5, 88.1, 81.6, 55.4, 43.9, 31.6, 17.0.
128.4, 123.4, 89.5. GC-MS: 178.
GC-MS: 208.
1-Methoxy-3-(phenylethynyl)benzene9 (4ba). 76 mg, 73%
3-(o-Tolylethynyl)thiophene13 (4ce). 65 mg, 66% yield, yellow
yield, yellow solid, mp: 63–64 C. H NMR (400 MHz, CDCl3-d) oil. 1H NMR (400 MHz, CDCl3-d) d 7.51 (dt, J ¼ 3.0, 1.0 Hz, 1H),
d 7.55–7.51 (m, 2H), 7.34 (d, J ¼ 5.1 Hz, 3H), 7.24 (d, J ¼ 7.5 Hz, 7.48 (d, J ¼ 7.4 Hz, 1H), 7.31–7.29 (m, 1H), 7.24–7.13 (m, 4H),
1H), 7.13 (d, J ¼ 7.2 Hz, 1H), 7.06 (s, 1H), 6.92–6.86 (m, 1H), 3.81 2.50 (s, 3H). 13C NMR (101 MHz, CDCl3-d) d 140.2, 131.9, 130.0,
(s, 3H). 13C NMR (101 MHz, CDCl3-d) d 159.3, 131.6, 129.4, 129.6, 128.4, 128.4, 125.7, 125.5, 123.1, 122.6, 88.4, 87.9, 20.9.
128.3, 128.3, 124.2, 124.1, 123.1, 116.3, 114.9, 89.3, 89.2, 55.2. GC-MS: 198.
1
ꢀ
GCMS: 208.
1-((4-Chlorophenyl)ethynyl)-3-methoxybenzene
1-Methoxy-2-(phenylethynyl)benzene14 (4da). 73 mg, 70%
(4bb). yield, yellow oil. H NMR (400 MHz, CDCl3-d) d 7.61–7.55 (m,
1
75 mg, yield: 62%, yellow solid, mp: 95–97 ꢀC. 1H NMR (400 2H), 7.52 (dd, J ¼ 7.5, 1.3 Hz, 1H), 7.37–7.29 (m, 4H), 6.98–6.89
MHz, CDCl3-d) d 7.45 (d, J ¼ 8.5 Hz, 2H), 7.34–7.30 (m, 2H), (m, 2H), 3.92 (s, 3H). 13C NMR (101 MHz, CDCl3-d) d 160.1,
7.26–7.22 (m, 1H), 7.11 (d, J ¼ 7.5 Hz, 1H), 7.06–7.03 (m, 1H), 133.7, 131.8, 129.9, 128.4, 128.2, 123.7, 120.6, 112.6, 110.8, 85.9,
6.92–6.88 (m, 1H), 3.82 (s, 3H). 13C NMR (101 MHz, CDCl3-d) 56.0. GC-MS: 208.
d 159.3, 134.3, 132.8, 129.5, 128.7, 124.1, 123.9, 121.7, 116.3,
115.1, 90.2, 88.0, 55.1. GC-MS: 242.
1-Methoxy-4-(phenylethynyl)benzene14 (4ea). 81 mg, 78%
yield, yellow solid, mp: 57–59 C. H NMR (400 MHz, CDCl3-d)
1
ꢀ
1-((4-Fluorophenyl)ethynyl)-3-methoxybenzene (4bc). 81 mg, d 7.56–7.51 (m, 2H), 7.49 (d, J ¼ 8.8 Hz, 2H), 7.38–7.29 (m, 3H),
72% yield, yellow oil. H NMR (400 MHz, CDCl3-d) d 7.53–7.48 6.89 (d, J ¼ 8.6 Hz, 2H), 3.83 (s, 3H). 13C NMR (101 MHz, CDCl3-
1
(m, 2H), 7.25 (t, J ¼ 8.0 Hz, 1H), 7.13–7.10 (m, 1H), 7.06–7.01 (m, d) d 159.7, 133.2, 131.6, 128.4, 128.1, 123.7, 115.5, 114.1, 89.5,
3H), 6.91–6.87 (m, 1H), 3.81 (s, 3H). 13C NMR (101 MHz, CDCl3- 88.20, 55.4. GC-MS: 208.
d) d 162.5 (d, J ¼ 249.5 Hz), 159.3, 133.5 (d, J ¼ 8.2 Hz), 129.4,
1-Chloro-3-(phenylethynyl)benzene15 (4fa). 48 mg, 45% yield,
124.1, 124.0, 119.2 (d, J ¼ 3.4 Hz), 116.3, 115.6 (d, J ¼ 22.1 Hz), white solid, mp: 30–32 ꢀC. 1H NMR (400 MHz, CDCl3-d) d 7.54–
114.9, 88.9, 88.1, 55.2. GC-MS: 226.
7.50 (m, 3H), 7.42–7.39 (m, 1H), 7.37–7.34 (m, 3H), 7.32–7.26
1-Methoxy-3-(p-tolylethynyl)benzene10 (4bd). 70 mg, 63% (m, 2H). 13C NMR (101 MHz, CDCl3-d) d 134.1, 131.7, 131.4,
1
ꢀ
yield, yellow solid, mp: 63–64 C. H NMR (400 MHz, CDCl3-d) 129.7, 129.5, 128.6, 128.5, 128.4, 125.0, 122.7, 90.5, 87.9. GC-MS:
d 7.43 (d, J ¼ 7.8 Hz, 2H), 7.23 (d, J ¼ 7.9 Hz, 1H), 7.13 (dd, J ¼ 212.
11.1, 7.9 Hz, 3H), 7.05 (s, 1H), 6.88 (d, J ¼ 8.2 Hz, 1H), 3.81 (s,
Methyl 3-((4-uorophenyl)ethynyl)benzoate (4gc). 56 mg,
2H), 2.36 (s, 2H). 13C NMR (101 MHz, CDCl3-d) d 159.3, 138.4, 44% yield, white solid, mp: 73–75 ꢀC. 1H NMR (400 MHz, CDCl3-
131.5, 129.3, 129.1, 124.4, 124.1, 120.0, 116.2, 114.8, 89.4, 88.6, d) d 8.20 (s, 1H), 8.00 (d, J ¼ 7.8 Hz, 1H), 7.69 (d, J ¼ 7.7 Hz, 1H),
55.2, 21.5. GC-MS: 222.
7.55–7.50 (m, 2H), 7.43 (t, J ¼ 7.8 Hz, 1H), 7.06 (t, J ¼ 8.6 Hz, 2H),
3-((3-Methoxyphenyl)ethynyl)thiophene (4be). 80 mg, 75% 3.94 (s, 3H). 13C NMR (101 MHz, CDCl3-d) d 166.5, 162.8 (d, J ¼
1
yield, yellow oil. H NMR (400 MHz, CDCl3-d) d 7.53–7.50 (m, 250.0 Hz), 135.8, 133.7 (d, J ¼ 8.5 Hz), 132.8, 130.6, 129.4, 128.7,
1H), 7.28 (dd, J ¼ 5.0, 3.0 Hz, 1H), 7.25–7.19 (m, 2H), 7.11 (d, J ¼ 123.7, 119.1 (d, J ¼ 3.4 Hz), 115.9 (d, J ¼ 22.1 Hz), 89.3, 88.1,
7.5 Hz, 1H), 7.04 (dd, J ¼ 2.4, 1.4 Hz, 1H), 6.88 (dd, J ¼ 8.3, 52.4. GC-MS: 254.
2.5 Hz, 1H), 3.80 (s, 3H). 13C NMR (101 MHz, CDCl3-d) d 159.3,
3-(Phenylethynyl)benzonitrile14 (4ha). 36 mg, 35% yield,
129.8, 129.4, 128.7, 125.4, 124.1, 124.0, 122.2, 116.2, 114.9, 88.8, yellow solid, mp: 68–70 ꢀC. 1H NMR (400 MHz, CDCl3-d) d 7.79
84.3, 55.2. GC-MS: 214.
(s, 1H), 7.72 (d, J ¼ 7.8 Hz, 1H), 7.59 (d, J ¼ 7.8 Hz, 1H), 7.53 (dd,
1-(Cyclohex-1-en-1-ylethynyl)-3-methoxybenzene11
(4bf). J ¼ 6.5, 2.9 Hz, 2H), 7.45 (t, J ¼ 7.8 Hz, 1H), 7.38–7.35 (m, 3H).
70 mg, 66% yield, yellow oil. 1H NMR (400 MHz, CDCl3-d) d 7.20 13C NMR (101 MHz, CDCl3-d) d 135.6, 134.9, 131.7, 131.3, 129.2,
(t, J ¼ 8.0 Hz, 1H), 7.04–7.01 (m, 1H), 6.97–6.94 (m, 1H), 6.86– 129.0, 128.5, 124.9, 122.2, 118.1, 112.8, 91.8, 86.9. GC-MS: 203.
6.82 (m, 1H), 6.22 (dt, J ¼ 4.1, 2.2 Hz, 1H), 3.79 (s, 3H), 2.25–2.21
1-Bromo-4-(phenylethynyl)benzene16 (4ia). 62 mg, 48% yield,
(m, 2H), 2.15 (dq, J ¼ 6.0, 3.7 Hz, 2H), 1.65 (dddd, J ¼ 20.4, 9.0, white solid, mp: 82–83 ꢀC. 1H NMR (400 MHz, CDCl3-d) d 7.55–
This journal is © The Royal Society of Chemistry 2017
RSC Adv., 2017, 7, 28308–28312 | 28311

View Article Online
RSC Advances
Paper
7.45 (m, 4H), 7.4–7.31 (m, 5H). 13C NMR (101 MHz, CDCl3-d)
d 133.0, 131.6, 128.5, 128.4, 122.9, 122.4, 122.2, 90.5, 88.3. GC-
MS: 256.
1-Iodo-3-(phenylethynyl)benzene17 (4ja). 73 mg, 48% yield,
white solid, mp: 83–85 ꢀC. 1H NMR (400 MHz, CDCl3-d) d 7.90 (t,
J ¼ 1.6 Hz, 1H), 7.68–7.65 (m, 1H), 7.54–7.48 (m, 3H), 7.37–7.34
(m, 3H), 7.08 (t, J ¼ 7.8 Hz, 1H). 13C NMR (101 MHz, CDCl3-d)
d 140.1, 137.2, 131.6, 130.7, 129.8, 128.6, 128.4, 125.3, 122.7,
93.79, 90.7, 87.6. GC-MS: 304.
(Cyclohexylethynyl)benzene18 (4ka). 40 mg, 44 yield, yellow
oil. 1H NMR (400 MHz, CDCl3-d) d 7.42–7.36 (m, 2H), 7.31–7.24
(m, 3H), 2.61–2.55 (m, 1H), 1.91–1.85 (m, 2H), 1.77–1.74 (m,
2H), 1.58–1.51 (m, 3H), 1.38–1.31 (m, 3H). 13C NMR (101 MHz,
CDCl3-d) d 131.7, 128.2, 127.5, 124.2, 94.6, 80.6, 32.8, 29.8, 26.0,
25.0. GC-MS: 184.
4208; (c) J.-H. Li, B.-X. Tang, L.-M. Tao, Y.-X. Xie, Y. Liang
and M.-B. Zhang, J. Org. Chem., 2006, 71, 7488.
4 (a) C. Liu, D. Liu and A. Lei, Acc. Chem. Res., 2014, 47, 3459;
(b) C. Liu, H. Zhang, W. Shi and A. Lei, Chem. Rev., 2011, 111,
1780; (c) W. Shi, C. Liu and A. Lei, Chem. Soc. Rev., 2011, 40,
2761; (d) K. M. Liu, L. Y. Liao and X. F. Duan, Chem.
Commun., 2015, 51, 1124; (e) K. M. Liu, J. Wei and
X. F. Duan, Chem. Commun., 2015, 51, 4655; (f) J. Yu, J. Liu,
G. Shi, C. Shao and Y. Zhang, Angew. Chem., Int. Ed., 2015,
54, 4079; (g) Y. Zhu, T. Xiong, W. Han and Y. Shi, Org.
Lett., 2014, 16, 6144; (h) C. Theunissen and G. Evano, Org.
Lett., 2014, 16, 4488; (i) T. Yasukawa, H. Miyamura and
S. Kobayashi, Org. Biomol. Chem., 2011, 9, 6208.
5 J. Jiao, S. Wang, C. Chen, Q. Liu and C. Xi, Organometallics,
2016, 35, 1415.
6 S. R. Dubbaka, M. Kienle, H. Mayr and P. Knochel, Angew.
Chem., Int. Ed., 2007, 46, 9093.
Acknowledgements
¨
7 (a) T. Klatt, J. T. Markiewicz, C. Samann and P. Knochel, J.
This work was supported by the National Natural Science
Foundation of China (21472106 and 91645120) and the
National Key Basic Research Program of China (973 program)
(2012CB933402).
Org. Chem., 2014, 79, 4253; (b) R. L. Bao, R. Zhao and
L. Shi, Chem. Commun., 2015, 51, 9744.
¨
8 D. Gallego, A. Bruck, E. Irran, F. Meier, M. Kaupp, M. Driess
and J. F. Hartwig, J. Am. Chem. Soc., 2013, 135, 15617.
9 G. C. Edwin Raja, F. M. Irudayanathan, H. Kim, J. Kim and
S. Lee, J. Org. Chem., 2016, 81, 5244.
10 J. Mao, G. Xie, M. Wu, J. Guo and S. Ji, Adv. Synth. Catal.,
2008, 350, 2477.
11 S. Urgaonkar and J. G. Verkade, J. Org. Chem., 2004, 69, 5752.
12 M. Chen, X. Zheng, W. Li, J. He and A. Lei, J. Am. Chem. Soc.,
2010, 132, 4101.
13 K. Kiyokawa, N. Tachikake, M. Yasuda and A. Baba, Angew.
Chem., Int. Ed., 2011, 50, 10393.
Notes and references
1 (a) K. C. Nicolaou and W. M. Dai, Angew. Chem., Int. Ed.,
1991, 30, 1387; (b) P. J. Stang and F. Diederich, Modern
Acetylene Chemistry, Wiley-VCH, Weinheim, 1995; (c)
M. C. Joshi and D. S. Rawat, Chem. Biodiversity, 2012, 9,
459; (d) F. Monnier and M. Taillefer, Angew. Chem., Int. Ed.,
2008, 47, 3096; (e) G. Evano, N. Blanchard and M. Toumi,
Chem. Rev., 2008, 108, 3054; (f) C. S. Yeung and
V. M. Dong, Chem. Rev., 2011, 111, 1215.
14 H. Huang, H. Jiang, K. Chen and H. Liu, J. Org. Chem., 2008,
73, 9061.
2 (a) H. Doucet and J. Hierso, Angew. Chem., Int. Ed., 2007, 46,
834; (b) M. Eckhardt and G. C. Fu, J. Am. Chem. Soc., 2003,
125, 13642; (c) K. Sonogashira, J. Organomet. Chem., 2002,
653, 46; (d) K. Sonogashira, Y. Tohda and N. Hagihara,
Tetrahedron Lett., 1975, 16, 4467; (e) K. Okuro, M. Furuune,
M. Mura and M. Nomura, Tetrahedron Lett., 1992, 33, 5363.
3 (a) J. K. Stille, Angew. Chem., Int. Ed., 1986, 25, 508; (b)
S.-K. Kang, J.-S. Kim and S.-C. Choi, J. Org. Chem., 1997, 62,
15 K. Park, G. Bae, J. Moon, J. Choe, K. H. Song and S. Lee, J.
Org. Chem., 2010, 75, 6244.
16 C. Lin, Y. Wang and C. Lee, Eur. J. Org. Chem., 2010, 4368.
17 A. Orita, H. Taniguchi and J. Otera, Chem.–Asian J., 2006, 1,
430.
18 G. Cahiez, O. Gager and J. Buendia, Angew. Chem., Int. Ed.,
2010, 49, 1278.
28312 | RSC Adv., 2017, 7, 28308–28312
This journal is © The Royal Society of Chemistry 2017