Copper(II) acetate/1,4-diphenyl-1,4-diazabuta-1,3-diene catalyzed sonogashira cross-coupling of aryl halides with terminal alkynes under aerobic and solvent-free conditions

Article abstract of DOI:10.1055/s-2006-950207

The Sonogashira cross-coupling of aryl halides with terminal alkynes catalyzed by an inexpensive copper(II) acetate/1,4-diphenyl-1,4-diazabuta-1,3- diene [Cu(OAc)₂/DAB-Ph] catalytic system is reported. A series of ligands, including diazabutadiene systems, N,N-dimethylglycine, L-proline, ethylenediamine, and phosphines, were evaluated, and 1,4-diphenyl-1,4-diazabuta- 1,3-diene provided the best results. In the presence of copper(II) acetate (10 mol%), 1,4-diphenyl-1,4-diazabuta-1,3-diene (20 mol%), and tetrabutylammonium fluoride (3 equiv), a number of aryl iodides or bromides were treated smoothly with alkynes to afford the corresponding products in moderate to excellent yields. It is noteworthy that the reaction is conducted under aerobic and solvent-free conditions. Georg Thieme Verlag Stuttgart.

Full text of DOI:10.1055/s-2006-950207

3
370
PAPER
Copper(II) Acetate/1,4-Diphenyl-1,4-diazabuta-1,3-diene Catalyzed
Sonogashira Cross-Coupling of Aryl Halides with Terminal Alkynes under
Aerobic and Solvent-Free Conditions
S
C
onogashira Cros
h
s-Coupling o
e
f
Aryl Ha
l
n
ide
s
w
ith Te
-
r
minal
A
L
lkynes iang Deng, Ye-Xiang Xie, Du-Lin Yin, Jin-Heng Li*
Key Laboratory of Chemical Biology & Traditional Chinese Medicine Research (Ministry of Education), College of Chemistry and
Chemical Engineering, Hunan Normal University, Changsha 410081, P. R. of China
Fax +86(731)8872531; E-mail: jhli@hunnu.edu.cn
Received 2 May 2006; revised 6 June 2006
lytic system for the coupling of aryl iodides or bromides.8d
Abstract: The Sonogashira cross-coupling of aryl halides with ter-
Although 1,10-phenanthroline (phen) was used as a ligand
minal alkynes catalyzed by an inexpensive copper(II) acetate/1,4-
in the Cu(phen)(PPh )Br or [Cu(phen)(PPh ) ]NO cata-
diphenyl-1,4-diazabuta-1,3-diene [Cu(OAc) /DAB-Ph] catalytic
3
3 2
3
2
system is reported. A series of ligands, including diazabutadiene lyzed Sonogashira coupling, the substrates were aryl io-
9
systems, N,N-dimethylglycine, L-proline, ethylenediamine, and dides and vinyl iodides. Furthermore, almost all of these
phosphines, were evaluated, and 1,4-diphenyl-1,4-diazabuta-1,3-
protocols must be performed under an inert gas to reduce
diene provided the best results. In the presence of copper(II) acetate
the occurrence of the Glaser reaction (the oxidative homo-
(
10 mol%), 1,4-diphenyl-1,4-diazabuta-1,3-diene (20 mol%), and
10
coupling of terminal alkynes) and using harmful sol-
tetrabutylammonium fluoride (3 equiv), a number of aryl iodides or
bromides were treated smoothly with alkynes to afford the corre-
sponding products in moderate to excellent yields. It is noteworthy
vents (DMF, DMSO, dioxane, or toluene etc.) as the
media. In view of economic and environmental require-
that the reaction is conducted under aerobic and solvent-free condi- ments, the challenge is to develop more active copper cat-
tions.
alytic systems to allow direct coupling of a large range of
aryl halides with alkynes under aerobic and solvent-free
conditions. Here, we wish to report a highly active and in-
expensive catalytic system that employs tetrabutylammo-
nium fluoride as a base and 1,4-diphenyl-1,4-diazabuta-
Key words: copper(II) acetate, diazabutadiene, Sonogashira cross-
coupling reaction, aryl halide, terminal alkyne
1
,3-diene (DAB-Ph) as a ligand for copper(II) acetate cat-
The cross-coupling of aryl halides with terminal alkynes
alyzed couplings of aryl halides with terminal alkynes
without the aid of degasification and without solvent
(Equation 1).11 Moreover, the presence of either N,N-di-
methylformamide or inert gas has a deleterious effect on
the reaction.
(
the Sonogashira cross-coupling reaction) represents one
of the most valuable synthetic methods in organic chem-
istry. Generally, a palladium(0) complex is chosen, in-
variably as the catalyst in the presence of a ligand (often a
1
–9
2
–6
phosphine). However, the palladium catalysts are ex-
pensive; to satisfy economic concerns, the use of inexpen-
7
–9
Cu(OAc)2 (10 mol%)
DAB-Ph (20 mol%)
sive metals as catalysts could be a solution to this
problem, as well as the recovery and recycling of the ex-
X
+
R'
R'
2
,6
R
TBAF (3 equiv), 130–135 °C
R
pensive palladium catalysts. Among the inexpensive
metals catalysts, copper catalysts, such as copper(I) io-
X = I, Br
dide, Cu(phen)(PPh )Br, and copper nanoclusters, have Equation 1
3
been employed in the Sonogashira cross-coupling reac-
8
,9
tion. However, there are only a few reports of the exten-
sion of the Sonogashira reaction to aryl bromides.8
Miura and co-workers first reported the copper-catalyzed
Sonogashira reaction, but the scope was limited to aryl io-
Our preliminary study was carried out on the cross-cou-
pling of 1-iodo-4-methoxybenzene (1a) with phenylacet-
ylene (2a), a model reaction, under aerobic and solvent-
free conditions (Table 1). To the best of our knowledge,
only two divalent copper salts [CuCl and Cu(OAc) ]
b–d
8
a
8b
dides. In 2004, Rothenberg and co-workers reported
that the Sonogashira reaction of aryl iodides and activated
aryl bromides catalyzed by copper nanoclusters gave sat-
isfactory results under ligand-free conditions. Ma and
2
2
were evaluated for the Sonogashira reaction of iodoben-
zene with phenylacetylene using N,N-dimethylformamide
as the medium and potassium carbonate as the base under
8
c
Liu found that copper(I) iodide combined with N,N-di-
methylglycine as the catalytic system could couple deac-
tivated aryl bromides. Guo and co-worker have also
employed copper(I) iodide/ethylenediamine as the cata-
8a
nitrogen. The results showed that the reaction catalyzed
by copper(II) chloride/triphenylphosphine was unsuc-
cessful, but copper(II) acetate/triphenylphosphine was
found to be an effective catalytic system for the coupling
(
diphenylacetylene; 88% yield, and 1,4-diphenylbuta-
diyne, 5% yield). Thus, we decided to perform the reac-
tion of the iodide 1a with alkyne 2a, copper(II) acetate,
triphenylphosphine (L1), and potassium carbonate under
SYNTHESIS 2006, No. 20, pp 3370–3376
x
x.
x
x
.
2
0
0
6
Advanced online publication: 21.08.2006
DOI: 10.1055/s-2006-950207; Art ID: F07006SS
Georg Thieme Verlag Stuttgart · New York
©

PAPER
Sonogashira Cross-Coupling of Aryl Halides with Terminal Alkynes
3371
solvent-free conditions. Unfortunately, the target product base; however, the yield of 3 increased only slightly (15%
was obtained in only 10% yield together with 1,4-diphe- yield; Table 1, entry 2). Another phosphine ligand, tricy-
nylbutadiyne (4) in 56% yield after 24 hours under air clohexylphosphine (L2), gave almost identical results
Table 1, entry 1). Very recently, we reported a fast and (Table 1, entry 3). It is pleasing to observe that treatment
3
(
general dichlorobis(triphenylphosphine)palladium cata- of 1a with alkyne 2a, copper(II) acetate, and tetrabutylam-
lyzed Sonogashira cross-coupling reaction under solvent- monium fluoride afforded a 43% yield of 3 without the aid
5
a
free conditions; tetrabutylammonium fluoride was ob- of any ligands and solvents (Table 1, entry 4). The results
served to be an effective base for the reaction. Thus, tet- encouraged us to further explore and optimize the condi-
rabutylammonium fluoride was examined as a suitable tions. Initially, a series of alternative ligands, including
Table 1 Copper-Catalyzed Sonogashira Cross-Coupling Reaction of 1-Iodo-4-methoxybenzene (1a) with Phenylacetylene (2a)a
MeO
I
+
Ph
MeO
Ph
+
Ph
Ph
1a
2a
3
4
b
Entry
[Cu]
Ligand
Time (h)
Yield (%)
3
4
1c
2
3
4
5
6
7
8
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Ph3P
Ph3P
Cy3P
–
L1
24
20
20
21
20
20
20
14
10
15
13
43
70
59
21
86
56
35
30
53
trace
26
44
0
L1
L2
–
Me NCH CO H·HCl
L3
L4
L5
L6
2
2
2
L-proline
H NCH CH NH
2
2
2
2
PhN
NPh
9
Cu(OAc)2
Cu(OAc)2
L7
L8
14
14
81
84
0
0
MesN
NMes
1
1
1
1
0
1
2
3
(
4-Ph)C6H4N
NC6H4(4-Ph)
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
L9
19
14
14
85
56
78
0
CyN
NCy
L10
L11
trace
0
n-C12H25N
Cy-C=N
Nn-C12H25
N=C-Cy
1
4
Cu(OAc)2
L12
20
66
trace
N
N
1
1
1
1
5
CuI
L6
L6
L6
L6
L6
20
18
15
14
14
45
26
18
29
trace
0
6
CuO
trace
28
7d
8e
9f
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
60
1
85
a
Unless otherwise indicated, the reaction conditions were as follows: 1a (0.5 mmol), 2a (0.65 mmol), [Cu] (10 mol%), ligand (20 mol%), TBAF
3 equiv), air, 130–135 °C.
Isolated yield. Yield of 4 on base of the amount of 2a.
(
b
c
d
e
f
K CO (3 equiv) was used as the base instead of TBAF.
2
3
DMF (1 mL) was added.
Under argon.
Under O (1 atm) instead of air.
2
Synthesis 2006, No. 20, 3370–3376 © Thieme Stuttgart · New York

3
372
C.-L. Deng et al.
PAPER
N,N-dimethylglycine (L3), L-proline (L4), ethylenedi- ucts even in the presence of tetrabutylammonium bromide
amine (L5), and diazabutadienes L6–L12, were examined (Table 2, entries 17 and 19). However, satisfactory yields
to improve the catalytic efficacy (Table 1, entries 5–14). were obtained when the reactions of 1i–k were conducted
We found that diazabutadienes L6–L12 as the ligands in the presence of 50 mol% of copper(II) acetate and 100
were superior to the earlier reported effective ligands, mol% of 1,4-diphenyl-1,4-diazabuta-1,3-diene (L6) at
8c
such as N,N-dimethylglycine hydrochloride (L7), L-pro- 140–145 °C (Table 2, entries 16, 18, and 20).
8
c
8d
line (L4), and ethylenediamine (L5), in terms of reac-
tion rate and yield. Among the diazabutadienes L6–L12,
It was interesting to find that the Sonogashira reaction and
deprotection occurred in one pot between aryl iodides and
prop-2-ynyl acetate (2d) to produce the corresponding
alk-2-yn-1-ols in good yields (Scheme 1).
1
,4-diphenyl-1,4-diazabuta-1,3-diene (DAB-Ph, L6) was
the most efficient ligand based on yield (Table 1, entries
–14). The use of other copper sources, such as copper(I)
8
iodide and copper(II) oxide, were also tested in air as the
catalyst and they were less effective than copper(II) ace-
tate (Table 1, entries 8, 15, and 16). To our surprise, the
yield of 3 decreased sharply to 28% when N,N-dimethyl-
Cu(OAc)2 (10 mol%)
L6 (20 mol%)
R
CH2OH
R
I +
CH2OAc
TBAF (3 equiv)
1
30–135 °C, 14 h R = OMe (68% yield; 7)
R = NO2 (76% yield; 15)
1
a and 1b
2d
8
a
formamide (1 mL), the previously reported solvent, was
added (Table 1, entry 17). It is noteworthy that argon has Scheme 1
a deleterious effect on the reaction mediated by copper(II)
acetate (Table 1, entries 8 and 18). Under argon, the yield
It is well known that copper(II) acetate can mediate the
Glaser coupling of terminal alkynes to afford diynes, and
this reaction often requires the presence of oxygen. To
our surprise, zero or low yields of diynes were observed
under the conditions used. Thus, some control reactions
of 3 was reduced to 60% (Table 1, entry 18). The effect of
oxygen was also examined; results identical to those in air
were observed when the reaction was carried out under an
oxygen atmosphere (Table 1, entry 19).
10
With the optimized reaction conditions in hand, we were were carried out to explore the mechanism of the copper-
keen to explore the range of substrates, including aryl ha- catalyzed Sonogashira cross-coupling (Table 3). Several
lides and terminal alkynes, that could be used in the cou- conclusions can be drawn, including: (1) The addition of
pling protocol. As shown in Table 2, the copper(II) 1,4-diphenyl-1,4-diazabuta-1,3-diene (L6) could sup-
acetate/1,4-diphenyl-1,4-diazabuta-1,3-diene (L6) cata- press the occurrence of the oxidative homocoupling of ter-
lytic system proved to be exceptionally active for the So- minal alkynes. Without a ligand present, using copper(II)
nogashira reaction of various aryl iodides 1a–f with acetate as the catalyst and tetrabutylammonium fluoride
alkynes. In the presence of copper(II) acetate (10 mol%), as the base, the target product 3 was produced in 43%
1
,4-diphenyl-1,4-diazabuta-1,3-diene (L6, 20 mol%), and yield together with the homocoupling product 4 in 53%
tetrabutylammonium fluoride (3 equiv), substrate 1a was yield (Table 3, entry 1), whereas the use of 1,4-diphenyl-
treated with alkynes 2b and 2c, respectively, to afford the 1,4-diazabuta-1,3-diene (L6) (20 mol%) shifted the selec-
corresponding products in good yields (Table, entries 1 tivity toward the cross-coupling reaction providing 3 in
and 2), but with alkyne 2d bearing an unprotected hy- 86% yield with no homocoupling product 4 formed
droxy group, the reaction was unsuccessful (Table 2, en- (Table 3, entry 2). (2) Argon in place of air suppressed the
try 3). The other aryl iodides 1b–f were coupled with copper(II) acetate catalyzed reaction, but favored the cop-
alkynes 2a and 2b smoothly in good to excellent yields per(I) iodide catalyzed procedure (Table 3, entries 2–5).
under the same conditions (Table 2, entries 4–10). How- In other words, oxygen can promote the copper(II) acetate
ever, the efficiency of copper(II) acetate/1,4-diphenyl- catalyzed Sonogashira protocol. The yield of 3 was re-
1
,4-diazabuta-1,3-diene (L6) decreased to some extent for duced from 86% (in air) to 60% (under argon) using cop-
the coupling of aryl bromides 1g–k (Table 2, entries 11– per(II) acetate/1,4-diphenyl-1,4-diazabuta-1,3-diene (L6)
1
7). For example, only a 43% yield of the desired product as the catalytic system (Table 3, entries 2 and 3). By con-
8
was isolated after 19 hours when 1-bromo-4-nitroben- trast, the yield of 3 increased from 45% (in air) to 65%
zene (1g) was reacted with phenylacetylene (2a), cop- (under argon) and the yield of 4 decreased when copper(I)
per(II) acetate (10 mol%), 1,4-diphenyl-1,4-diazabuta- iodide was used in place of copper(II) acetate (Table 3,
1
(
,3-diene (20 mol%), and tetrabutylammonium fluoride entries 4 and 5). (3) Copper(II) acetate is not a good cata-
3 equiv) (Table 2, entry 11). We were happy to observe lyst for the homocoupling reaction under the optimized
that tetrabutylammonium bromide could improve the re- conditions. In the absence of 1a, alkyne 2a was consumed
action. The yield of 8 was enhanced to 69% when tetrabu- completely in 15 hours [Cu(OAc) (10 mol%), DAB-Ph
2
tylammonium bromide (1 equiv) was added (Table 2, (L6) (20 mol%), TBAF (3 equiv), 130–135 °C] to afford
entry 12). Other bromides 1h and 1i underwent the reac- 4 in 27% yield (Table 3, entry 6). The yield of 4 was en-
tion smoothly to provide moderate yields in the present of hanced to 40% when N,N-dimethylformamide (2 mL) was
tetrabutylammonium bromide (Table 2, entries 14 and added (Table 3, entry 8). We found that the ligand 1,4-
1
5). It was found that the these reaction conditions were diphenyl-1,4-diazabuta-1,3-diene (L6) has no influence
less effective for the reaction of substrates 1j and 1k, on the homocoupling reaction (Table 3, entries 6 and 7).
which gave low yields of the corresponding desired prod- Employing copper(II) acetate and tetrabutylammonium
Synthesis 2006, No. 20, 3370–3376 © Thieme Stuttgart · New York

PAPER
Sonogashira Cross-Coupling of Aryl Halides with Terminal Alkynes
3373
Table 2 a Copper(II) Acetate/1,4-Diphenyl-1,4-diazabuta-1,3-diene (L6) Catalyzed Sonogashira Cross-Coupling of Aryl Halides with
Alkynes
b
Entry
1
Aryl halide
Alkyne
Time (h)
14
Product
Yield (%)
1a
HC≡C(CH ) Me
2b
5
87
2
7
MeO
I
2
3
4
1a
1a
1b
HC≡CCH OTHP
2c
2d
2a
14
14
14
6
7
8
84
2
HC≡CCH OH
trace
98
2
HC≡CPh
O2N
O
I
5
6
1b
1c
HC≡C(CH ) Me
2b
2a
14
16
9
95
70
2
7
HC≡CPh
10
I
I
7
8
9
1d
1e
HC≡CPh
HC≡CPh
2a
2a
14
14
11
12
85
93
I
Me
1e
1f
HC≡C(CH ) Me
2b
2a
14
14
13
14
91
85
2
7
1
0
HC≡CPh
I
Me
1
1
1g
HC≡CPh
HC≡CPh
2a
19
8
43
O2N
Br
1
1
1
2c
3c
4c
1g
1g
1h
2a
2b
2a
19
19
19
8
9
69
58
72
HC≡C(CH ) Me
2
7
O
HC≡CPh
10
Br
Br
1
5c
1i
HC≡CPh
2a
20
9
57
Br
1
1
6cd
7c
1i
1j
HC≡CPh
HC≡CPh
2a
2a
26
19
9
72
32
12
Me
1
1
8cd
9c
1j
HC≡CPh
HC≡CPh
2a
2a
24
23
12
3
70
21
1k
MeO
Br
2
0cd
1k
HC≡CPh
2a
23
3
40
a
b
c
d
Reaction conditions: 1 (0.5 mmol), 2 (0.65 mmol), Cu(OAc) ·H O (10 mol%), DAB-Ph (L6) (20 mol%), TBAF (3 equiv), 130–135 °C.
Isolated yield.
TBAB (1 equiv).
2
2
Cu(OAc) ·2 H O (50 mol%), DAB-Ph (L6) (100 mol%), 140–145 °C.
2
2
fluoride with methanol as the medium resulted in the com- To elucidate the results, a working mechanism was pro-
pleted consumption of 2a in three hours but gave 4 in only posed for this copper(II) acetate catalyzed Sonogashira
6
% yield (Table 3, entry 9). Under the same conditions, cross-coupling reaction, based on the reported mechanism
but using sodium acetate as the base, 4 was obtained in proposed by Miura8a and Rothenberg (Scheme 2).
8% yield (Table 3, entry 10). (4) N,N-Dimethylforma- Firstly, complexation of copper(II) acetate with the ligand
mide as the medium disfavored the target reaction. In led to the formation of a four-centered transition state 16,
8b
2,7–9
1
12
N,N-dimethylformamide, the yield of 3 decreased sharply which was observed by Castro and Stephens. Intermedi-
to 28%, while 4 was obtained in 29% yield (Table 3, en- ate 16 then reacted with readily with an alkyne with the
tries 2 and 11).
aid of a base to yield intermediate 17, and this was fol-
Synthesis 2006, No. 20, 3370–3376 © Thieme Stuttgart · New York

3
374
C.-L. Deng et al.
PAPER
Table 3 Control Reactions of 1-Iodo-4-methoxybenzene (1a) with Phenylacetylene (2a)a
MeO
I
+
Ph
MeO
Ph
+
Ph
Ph
1a
2a
3
4
Entry
[Cu]
Ligand
Solvent
Time (h)
Yieldbc (%)
3
4
1
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
CuI
–
neat
21
14
14
20
18
15
3
43
86
60
45
65
–
53
trace
trace
26
14
27
30
40
6
2
L6
L6
L6
L6
L6
–
neat
3d
4
neat
neat
5d
6e
7e
8e
9e
CuI
neat
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
Cu(OAc)2
neat
neat
–
L6
–
DMF
MeOH
MeOH
DMF
15
3
–
–
1
0ef
1
–
3
–
18
29
1
L6
15
28
a
Under otherwise indicated, the reaction conditions were as follows: 1a (0.5 mmol), 2a (0.65 mmol), [Cu] (10 mol%), DAB-Ph (L6) (20 mol%),
TBAF (3 equiv), air, 130–135 °C.
b
Isolated yield.
Yield of 4 based on the amount of 2a.
Under argon.
Without 1a.
c
d
e
f
NaOAc (3 equiv) was used instead of TBAF.
lowed by the oxidative addition of 17 to ArX to afford in- In summary, we have demonstrated an inexpensive cop-
termediate 18. The subsequent reductive elimination of 18 per(II) acetate/1,4-diphenyl-1,4-diazabuta-1,3-diene sys-
took place to produce the desired product and regenerate tem for the Sonogashira-type, cross-coupling reaction.
the active copper species 16. On the other hand, the homo- The system is effective for aryl iodides and activated aryl
coupling of terminal alkyne could be catalyzed by 17 to bromides, and emerges as an attractive alternative to the
afford the diyne 4.1 Further study to obtain a more accu- palladium/ligand catalyst systems. It is noteworthy that
0
rate mechanism for the reaction is underway.
the reaction is performed under aerobic and solvent-free
conditions. Further mechanistic and reactive studies of
this system in other cross-coupling transformations are in
progress.
Cu(OAc)2
3L
L3CuY
R
+ base
HbaseY
R
Ar
16
NMR spectroscopy was performed on Bruker AMX-300 or 400
2
3
and 5–15
1
13
spectrometers, operating at 300 MHz ( H NMR) and 75 MHz ( C
1
13
L
NMR) or 400 MHz ( H NMR) and 100 MHz ( C NMR). TMS was
used an internal standard.
Y = OAc, I, Br
X = I, Br
L
Copper(I) Iodide/1,4-Diphenyl-1,4-diazabuta-1,3-diene Cata-
lyzed Sonogashira Cross-Coupling Reactions; General Proce-
dure
A mixture of aryl halide 1 (0.5 mmol), alkyne 2 (0.65 mmol),
Cu(OAc)2 (10 mol%), DAB-Ph (L6, 20 mol%), and TBAF (3
equiv) was stirred at 130–135 °C for the desired time until complete
consumption of starting material as monitored by TLC. The mixture
L
Cu
X
Cu
L
1
L
L
R
7
R
Ar
18
ArX
1
L
L
was then dissolved in EtOAc (10 mL), filtered, washed with H O
Cu
R
R
2
L
L
4
(3 × 5 mL), extracted with Et O (5 × 10 mL) and evaporated. The
2
R
1
7
residue was purified by flash column chromatography (hexane or
hexane–EtOAc) to afford the product.
Scheme 2
Synthesis 2006, No. 20, 3370–3376 © Thieme Stuttgart · New York

PAPER
-Methoxy-4-(2-phenylethynyl)benzene (3)8c
Sonogashira Cross-Coupling of Aryl Halides with Terminal Alkynes
3375
13
1
C NMR (100 MHz, CDCl ): d = 197.4, 136.1, 131.8, 131.7, 128.8,
3
1
H NMR (400 MHz, CDCl ): d = 7.52–7.51 (m, 2 H), 7.48 (d,
128.4, 128.3, 122.6, 92.7, 88.6, 26.7.
3
J = 9.0 Hz, 2 H), 7.34–7.32 (m, 3 H), 6.88 (d, J = 8.8 Hz, 2 H), 3.83
+
LRMS (EI, 20 eV): m/z (%) = 220 (M , 100).
(
s, 3 H).
1
3
8c
C NMR (100 MHz, CDCl ): d = 159.6, 133.0, 131.4, 128.3, 127.9,
Diphenylacetylene (11)
3
1
1
23.6, 115.4, 114.0, 89.4, 88.1, 55.3.
H NMR (300 MHz, CDCl ): d = 7.60–7.51 (m, 4 H), 7.39–7.26 (m,
3
+
6 H).
LRMS (EI, 20 eV): m/z (%) = 208 (M , 100).
1
3
C NMR (75 MHz, CDCl ): d = 132.0, 128.7, 128.6, 123.7, 89.7.
3
1
,4-Diphenylbuta-1,3-diyne (4)8c
H NMR (400 MHz, CDCl ): d = 7.54 (d, J = 7.4 Hz, 4 H), 7.38–
.34 (m, 6 H).
+
LRMS (EI, 20 eV): m/z (%) = 178 (M , 100).
1
3
7
1
-(Phenylethynyl)toluene (12)8c
H NMR (300 MHz, CDCl ): d = 7.54–7.50 (m, 2 H), 7.43 (d,
J = 8.1 Hz, 2 H), 7.35–7.31 (m, 3 H), 7.15 (d, J = 7.8 Hz, 2 H), 2.36
4
3
1
C NMR (100 MHz, CDCl ): d = 132.8, 129.6, 128.8, 122.1, 81.9,
3
3
7
4.2.
+
(s, 3 H).
LRMS (EI, 20 eV): m/z (%) = 202 (M , 100).
1
3
C NMR (100 MHz, CDCl ): d = 138.7, 132.9, 131.9, 129.6, 129.5,
3
1
-(Dec-1-ynyl)-4-methoxybenzene (5)4
128.8, 128.7, 128.4, 89.1, 83.4, 21.9.
1
H NMR (400 MHz, CDCl ): d = 7.33 (d, J = 8.8 Hz, 2 H), 6.81 (d,
J = 8.8 Hz, 2 H), 3.80 (s, 3 H), 2.38 (t, J = 7.6 Hz, 2 H), 1.61–1.57
+
3
LRMS (EI, 20 eV): m/z (%) = 192 (M , 100).
(
m, 2 H), 1.45–1.40 (m, 2 H), 1.31–1.24 (m, 8 H), 0.88 (t, J = 6.4
-(Dec-1-ynyl)toluene (13)4
4
Hz, 3 H).
1
1
H NMR (400 MHz, CDCl ): d = 7.28 (d, J = 8.0 Hz, 2 H), 7.08 (d,
3
3
C NMR (100 MHz, CDCl ): d = 158.9, 132.8, 116.1, 113.7, 88.8,
J = 8.0 Hz, 2 H), 2.38 (t, J = 7.2 Hz, 2 H), 2.32 (s, 3 H), 1.61–1.55
(m, 2 H), 1.46–1.42 (m, 2 H), 1.31–1.29 (m, 8 H), 0.89 (t, J = 7.2
Hz, 3 H).
3
8
0.1, 55.2, 31.8, 29.2, 29.1, 28.9, 28.8, 22.7, 19.4, 14.1.
+
LRMS (EI, 20 eV): m/z (%) = 244 (M , 100).
1
3
C NMR (100 MHz, CDCl ): d = 137.4, 131.4, 128.9, 121.0, 89.6,
3
2
-[3-(4-Methoxyphenyl)prop-2-ynyloxy]tetrahydro-2H-pyran
80.6, 31.9, 29.2, 29.1, 28.9, 28.8, 23.7, 21.4, 18.4, 14.1.
8
c
(
6)
+
LRMS (EI, 20 eV): m/z (%) = 228 (M , 100).
1
H NMR (400 MHz, CDCl ): d = 7.39 (d, J = 8.8 Hz, 2 H), 6.83 (d,
3
J = 8.8 Hz, 2 H), 4.90 (t, J = 3.2 Hz, 1 H), 4.53–4.22 (m, 2 H), 3.89
t, J = 7.2 Hz, 1 H), 3.80 (s, 3 H), 3.58–3.54 (m, 1 H), 1.76–1.54 (m,
-(Phenylethynyl)toluene (14)4
2
(
1
H NMR (400 MHz, CDCl ): d = 7.53–7.52 (m, 3 H), 7.35–7.33 (m,
3
6
H).
4
H), 7.23–7.22 (m, 2 H), 2.52 (s, 3 H).
1
3
C NMR (100 MHz, CDCl ): d = 159.6, 133.3, 114.8, 113.8, 96.8,
13
3
C NMR (100 MHz, CDCl ): d = 140.2, 132.6, 131.9, 131.6, 129.5,
3
8
5.7, 83.6, 62.0, 55.2, 54.8, 30.3, 25.4, 19.1.
1
29.2, 128.4, 128.3, 128.2, 125.6, 88.4, 81.7, 20.7.
+
LRMS (EI, 20 eV): m/z (%) = 246 (M , 100).
+
LRMS (EI, 20 eV): m/z (%) = 192 (M , 100).
3
-(4-Methoxyphenyl)prop-2-yn-1-ol (7)4i
-(4-Nitrophenyl)prop-2-yn-1-ol (15)4i
3
1
H NMR (300 MHz, CDCl ): d = 7.38 (d, J = 8.8 Hz, 2 H), 6.84 (d,
J = 8.8 Hz, 2 H), 4.49 (s, 2 H), 3.82 (s, 3 H).
1
3
H NMR (300 MHz, CDCl ): d = 8.19 (d, J = 8.8 Hz, 2 H), 7.58 (d,
3
J = 8.8 Hz, 2 H), 4.54 (s, 2 H).
1
3
C NMR (75 MHz, CDCl ): d = 159.7, 133.2, 114.5, 113.9, 85.8,
13
3
C NMR (100 MHz, CDCl ): d = 147.3, 132.4, 129.4, 123.6, 92.5,
3
8
5.6, 55.3, 51.7.
8
3.8, 51.5.
+
+
LRMS (EI, 20 eV): m/z (%) = 162 (M , 100), 145 (M – OH, 33).
+
+
LRMS (EI, 20 eV): m/z (%) = 177 (M , 100), 160 (M – OH, 30).
1
-Nitro-4-(phenylethynyl)benzene (8)8c
1
H NMR (300 MHz, CDCl ): d = 8.21 (d, J = 8.8 Hz, 2 H), 7.65 (d,
J = 8.8 Hz, 2 H), 7.58–7.54 (m, 2 H), 7.40–7.38 (m, 3 H).
3
Acknowledgment
We thank Fok Ying Dong Education Foundation (No. 101012), the
Key Project of Chinese Ministry of Education (No. 206102), Scien-
tific Research Fund of Hunan Provincial Education Department
(No. 05B038), Hunan Provincial Natural Science Foundation of
China (No. 05JJ1002) and the National Natural Science Foundation
of China (Nos. 20572020 and 20202002) for financial support.
1
3
C NMR (75 MHz, CDCl ): d = 141.3, 132.6, 132.2, 130.6, 129.6,
3
1
28.8, 124.0, 122.5, 95.0, 87.9.
+
LRMS (EI, 20 eV): m/z (%) = 223 (M , 100).
1
-(Dec-1-ynyl)-4-nitrobenzene (9)4
H NMR (400 MHz, CDCl ): d = 8.15 (d, J = 8.8 Hz, 2 H), 7.51 (d,
1
3
J = 8.8 Hz, 2 H), 2.44 (t, J = 7.2 Hz, 2 H), 1.74–1.59 (m, 2 H), 1.47–
1
.43 (m, 2 H), 1.31–1.26 (m, 8 H), 0.89 (t, J = 7.2 Hz, 3 H).
References
1
3
C NMR (100 MHz, CDCl ): d = 132.6, 131.6, 123.8, 118.5, 97.2,
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3
7
9.6, 32.2, 29.5, 29.4, 29.3, 28.7, 23.0, 19.9, 14.4.
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LRMS (EI, 20 eV): m/z (%) = 259 (M , 100).
-(Phenylethynyl)acetophenone (10)2
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1
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Synthesis 2006, No. 20, 3370–3376 © Thieme Stuttgart · New York

3
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Synthesis 2006, No. 20, 3370–3376 © Thieme Stuttgart · New York