Atom-economical chemoselective synthesis of 1,4-enynes from terminal alkenes and propargylic alcohols catalyzed by Cu(OTf)2

Article abstract of DOI:10.1021/jo3026803

A novel and efficient Cu(OTf)₂-catalyzed sp³-sp ² C-C bond formation reaction through the direct coupling of propargylic alcohols with terminal alkenes has been realized under mild conditions. The reaction is tolerant to a

Full text of DOI:10.1021/jo3026803

Note
pubs.acs.org/joc
Atom-Economical Chemoselective Synthesis of 1,4-Enynes from
Terminal Alkenes and Propargylic Alcohols Catalyzed by Cu(OTf)2
Guo-Bao Huang,† Xu Wang,† Ying-Ming Pan,*,† Heng-Shan Wang,† Gui-Yang Yao,† and Ye Zhang*,‡
†Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources (Ministry of Education of China), School of
Chemistry & Chemical Engineering of Guangxi Normal University, Guilin 541004, People’s Republic of China
‡Department of Chemistry, Guilin Normal College, Guangxi 541001, People’s Republic of China
S
* Supporting Information
ABSTRACT: A novel and efficient Cu(OTf)2-catalyzed sp3−
sp2 C−C bond formation reaction through the direct coupling
of propargylic alcohols with terminal alkenes has been realized
under mild conditions. The reaction is tolerant to air and is
atom-economical, in accordance with the concept of modern
green chemistry. The present protocol provides an attractive
approach to a diverse range of 1,4-enynes in high to excellent yields.
ue to the electron-rich triple bond in combination with
1,4-enynes have been discovered to be one of the most efficient
Dthe fairly acidic features of the terminal acetylenic intermediates to access ring systems.5
Initially, we started to optimize the reaction parameters of
hydrogen atom, transition-metal-catalyzed nucleophilic reaction
of terminal alkynes has become an important organic reaction,
as it provides a direct and reliable approach to a wide variety of
valuable products.1 In contrast, related transition-metal-
catalyzed nucleophilic reaction of terminal alkenes is rare
because the C−H bond of simple alkenes is less reactive toward
transition metals. The flexibility of the alkene functional group
in organic synthesis makes the nucleophilic reaction of alkenes
a desirable method for development. In addition to allowing
access to saturated products by hydrogenation, the alkene
moiety offers a handle for transformation into various other
functional groups.
The nucleophilic substitution reactions of propargylic
alcohols under metal catalysis or Brøsted acid have been
recently extensively studied by using different nucleophiles such
as alcohol, 1,3-diketones, arenes, silylalkenes.2 Recently, an
FeCl3-catalyzed propargylic substitution reaction has been
developed for the synthesis of diarylalkenyl propargylic
compounds directly from propargylic alcohols with 1,1-diaryl
alkenes in moderate to good yields.3 However, the substrates
are limited to 1,1-diaryl alkenes, and slightly longer reaction
time is needed. Therefore, the development of a coupling
reaction for the synthesis of 1,4-enynes directly from simple
alkenes and propargylic alcohols is of significance. More
recently, we have reported a convenient one-pot synthesis of
4,5-dihydropyrazole from aldehydes, hydrazines, and terminal
alkenes using Cu(OTf)2 as a multifunctional catalyst, where the
alkenes were used as the nucleophile.4 Naturally we attempted
to extend the scope of the nucleophilic reaction of alkenes.
Herein, we wish to report an efficient Cu(OTf)2-catalyzed
nucleophilic substitution reaction of terminal alkenes with
propargylic alcohols bearing not only a terminal group but also
a internal alkyne group to afford 1,4-enynes in high yields with
complete regioselectivities under mild reaction conditions. The
this substitution reaction of alkenes with propargylic alcohols. A
variety of catalysts and solvents were screened using 1,3-
diphenylprop-2-yn-1-ol (1a) with styrene (2a) as a model
system (Table 1). The reaction of 1a and 2a gave 3aa in 90%
yield in the presence of 10 mol % Cu(OTf)2 in 1,2-
dichloroethane (DCE) at reflux for 10 min (Table 1, entry
1). However, no improvement in the yield of 3aa could be
obtained, as the amount of Cu(OTf)2 was increased to 15 mol
% (Table 1, entry 3). In addition, the substitution reactions
were obviously restrained when using CuCl, FeCl3, Pd(dba)2,
or Brøsted acid as catalyst (Table 1, entries 4−8). Further
optimization suggested that solvents also had a strong effect on
this process (Table 1, entries 1 and 9−14).
With these optimal conditions in hand, we decided to
explore the scope of this propargylic substitution reaction.
Typical results are shown in Table 2. Among the propargylic
alcohols 1a−1g that were examined, propargylic alcohol 1b
possessing an electron-donating group (R1 = 4-MeO-C6H4)
gave the most desirable results, providing the 1,4-enynes in 90−
95% yields (Table 2, entries 3−6). Substrate 1c possessing an
electron-withdrawing group (R1 = 4-F-C6H4) at the benzene
ring also reacted smoothly and afforded the desired products in
high yields (Table 2, entries 8−10). What’s more, fluorine has
come to be recognized as a key element in materials science,
and many fluorine-containing biologically active agents are
finding applications as pharmaceuticals and agrochemicals.6
Internal propargylic alcohol 1f (R2 = n-hexyl) also gave good
results (Table 2, entries 14 and 15). To our delight, the
reaction of terminal propargyl alcohol 1d (R2 = H) with styrene
2a gave 3da in 80% yield (Table 2, entry 12); this is in sharp
Received: December 11, 2012
Published: February 4, 2013
© 2013 American Chemical Society
2742
dx.doi.org/10.1021/jo3026803 | J. Org. Chem. 2013, 78, 2742−2745

The Journal of Organic Chemistry
Note
a
Table 1. Optimization of Reaction Conditions
Table 2. Synthesis of Substituted 1,4-Enynes 3 Catalyzed by
Cu(OTf)2
a
b
entry
catalyst
solvent
time
yield [%]
1
Cu(OTf)2
Cu(OTf)2
Cu(OTf)2
CuCl
DCE
10 min
90
72
91
12
20
16
0
c
2
DCE
15 h
d
3
DCE
10 min
10 h
10 h
10 h
24 h
24 h
24 h
24 h
24 h
24 h
24 h
24 h
24 h
24 h
4
DCE
5
CuI
DCE
6
Cu(OAc)2
FeCl3
DCE
5
DCE
6
Pd(dba)2
p-TSA
DCE
0
7
DCE
0
8
HOTf
DCE
0
9
Cu(OTf)2
Cu(OTf)2
Cu(OTf)2
Cu(OTf)2
Cu(OTf)2
Cu(OTf)2
MeCN
toluene
DMF
PhCl
0
10
11
12
13
14
0
0
0
CH3NO2
CHCl3
0
0
a
Reaction conditions: all reactions were carried out in a 5-mL flask
using 1 (0.5 mmol), 2 (0.6 mmol) and catalyst (0.05 mmol) in solvent
b
(2 mL) at reflux for 10 min. Isolated yield of pure product based on
c
d
1a. The amount of Cu(OTf)2 was decreased to 5 mol %. The
amount of Cu(OTf)2 was increased to 15 mol %.
contrast to the FeCl3-catalyzed reaction where the coupling
reaction of 1-phenylprop-2-yn-1-ol 1d with styrene 2a was
unsuccessful.3 Moreover, 1g (R2 = TMS) reacted smoothly
with 2a giving 3ga in 94% yield (Table 2, entry 16). Propargylic
alcohol bearing a heterocyclic aromatic substituent such as 3-
phenyl-1-(thiophen-2-yl)prop-2-yn-1-ol 1e treated with 2d also
led to the desired product 3ed in 93% yield (Table 2, entry 13).
Additionally, a variety of alkenes 2 were employed to
examine the generality of the method. Reactions of 4-
bromostyrene (2b), 4-acetoxystyrene (2c), and 4-methoxystyr-
ene (2e) with propargylic alcohol 1a gave the corresponding
1,4-enynes 3ab−3ae in 84−94% yields (Table 2, entries 1, 2,
and 11). Obviously, electron-rich alkenes provided the desired
products in higher yields than electron-poor alkenes did. In
particular, 1,1-diphenylethylene 2d (R3 = Ph, R4 = Ph)
provided the desired products in high yields (Table 2, entries
6, 7, 10, 13, and 15). These results suggest that the geminally
disubstituted alkenes are also good substrates on the propargyl
substitution reaction.
a
Reaction conditions: all reactions were carried out in a 5-mL flask
using 1 (0.5 mmol), 2 (0.6 mmol), and Cu(OTf)2 (0.05 mmol) in
DCE (2 mL) at reflux for 10 min. Isolated yield of pure product
b
Unfortunately, when aliphatic olefins were used as the
nucleophiles, substitution reactions of propargyl alcohols failed,
generating the corresponding propargylic ethers (Scheme 1).7
On the basis of our and others’ previous work,8 our
postulated reaction pathways are summarized in Scheme 2.
Two competitive pathways could occur, leading to the
formation of 1,4-enyne 3 and propargylic ether 4. In the initial
step, Cu(OTf)2 triggers the dehydroxylation of propargylic
alcohol 1 to form the intermediary propargylic cation A. The
subsequent nucleophilic reaction of aromatic olefins 2 to the
intermediary propargylic cation A leads to a stabilized benzylic
carbocation intermediate B (Path I). Finally, intermediate B
undergoes a dehydrogenation step to offer 1,4-enyne 3. When
aliphatic olefin is used, there is no benzylic stabilization,
disfavoring Path I. Instead, the oxygen atom of the propargylic
based on 1a.
Scheme 1. Synthesis of Propargylic Ether 4aa from
Propargylic Alcohol 1a
alcohol 1 attacks the intermediary propargylic cation A (Path
II), leading to an intermediate C, which undergoes a
dehydrogenation step to propargylic ether 4.
2743
dx.doi.org/10.1021/jo3026803 | J. Org. Chem. 2013, 78, 2742−2745

The Journal of Organic Chemistry
Note
21.0. HRAPCIMS calcd for C25H21O2 (M + H)+ 353.1542; found
353.1539.
Scheme 2. Proposed Mechanism
(E)-1-(1,5-Diphenylpent-1-en-4-yn-3-yl)-4-methoxybenzene
(3ba). A yellow oil in 93% yield (150 mg, 0.47 mmol); 1H NMR (500
MHz, CDCl3) δ 7.57−7.51 (m, 2H), 7.44−7.40 (m, 4H), 7.38−7.31
(m, 6H), 6.95 (d, J = 8.8 Hz, 2H), 6.79 (d, J = 15.6 Hz, 1H), 6.37 (dd,
J = 15.6 and 6.5 Hz, 1H), 4.75 (d, J = 6.5 Hz, 1H), 3.84 (s, 3H). 13C
NMR (125 MHz, CDCl3) δ 158.7, 136.9, 132.3, 131.7, 130.2, 129.9,
128.7, 128.5, 128.2, 127.9, 127.5, 126.5, 123.5, 114.1, 89.1, 85.2, 55.27,
40.36. HRAPCIMS calcd for C24H19O (M − H)+ 323.1436; found
323.1432.
(E)-1-Bromo-4-(3-(4-methoxypheyl)-5-phenylpent-1-en-4-
ynyl)benzene (3bb). A pale yellow oil in 90% yield (180 mg, 0.45
1
mmol); H NMR (500 MHz, CDCl3) δ 7.53−7.50 (m, 2H), 7.47−
7.40 (m, 5H), 7.37−7.32 (m, 3H), 7.30−7.24 (m, 1H), 7.04−6.87 (m,
2H), 6.71 (dd, J = 15.6 and 1.8 Hz, 1H), 6.35 (dd, J = 15.6 and 6.4 Hz,
13
1H), 4.72 (d, J = 6.4 Hz, 1H), 3.83 (s, 3H). C NMR (125 MHz,
CDCl3) δ 158.7, 135.8, 132.0, 131.7, 131.6, 130.7, 129.4, 128.9, 128.7,
128.3, 128.0, 123.3, 121.2, 114.1, 88.8, 85.3, 55.3, 40.3. HRAPCIMS
calcd for C24H18BrO (M − H)+ 401.0541, 403.0521; found 401.0594,
403.0569.
(E)-4-(3-(4-Methoxyphenyl)-5-phenylpent-1-en-4-ynyl)-
phenyl Acetate (3bc). A yellow oil in 93% yield (177 mg, 0.47
mmol); H NMR (500 MHz, CDCl3) δ 7.49−7.45 (m, 2H), 7.40−
In summary, we have documented a Cu-catalyzed reaction of
simple terminal alkenes with propargylic alcohols. This
operationally simple method gives a rapid access to the 1,4-
enynes. Air-tolerant and atom-economical characteristics of the
method are in accord with the concept of modern green
chemistry and will be appealing for industries. Further
development on this methodology is currently underway in
our laboratory.
1
7.36 (m, 4H), 7.34−7.30 (m, 3H), 7.04 (d, J = 8.7 Hz, 2H), 6.91 (d, J
= 8.7 Hz, 2H), 6.74 (d, J = 15.6 Hz, 1H), 6.28 (dd, J = 15.6 and 6.5
Hz, 1H), 4.71 (d, J = 6.5 Hz, 1H), 3.81 (s, 3H), 2.29 (s, 3H). 13C
NMR (125 MHz, CDCl3) δ 169.5, 158.8, 150.0, 134.8, 132.3, 131.7,
130.2, 129.2, 128.8, 128.3, 128.0, 127.5, 123.5, 121.7, 114.1, 89.0, 85.3,
55.4, 40.4, 21.1. HRAPCIMS calcd for C26H23O3 (M + H)+ 383.1647;
found 383.1629.
1-Methoxy-4-(1,1,5-triphenylpent-1-en-4-yn-3-yl)benzene
(3bd). A yellow oil in 95% yield (190 mg, 0.48 mmol); 1H NMR (500
MHz, CDCl3) δ 7.59−7.55 (m, 2H), 7.52−7.49 (m, 2H), 7.47−7.41
(m, 5H), 7.39- 7.30 (m, 8H), 6.96 (dd, J = 8.7 and 1.1 Hz, 2H), 6.31
(d, J = 10.1 Hz, 1H), 4.78 (d, J = 10.1 Hz, 1H), 3.86 (s, 3H). 13C
NMR (125 MHz, CDCl3) δ 158.5, 141.8, 141.4, 139.2, 132.7, 131.7,
129.9, 128.7, 128.5, 128.4, 128.2, 128.1, 127.9, 127.5, 127.4, 123.6,
113.9, 90.1, 83.8, 55.2, 37.1. HRAPCIMS calcd for C30H25O (M + H)+
401.1905; found 401.1883.
EXPERIMENTAL SECTION
■
General Description. Melting points are uncorrected. NMR
spectra were in CDCl3 (1H at 500 MHz and
C at 125 MHz).
13
Column chromatography was performed on silica gel (300−400
mesh). Unless otherwise noted, all reagents were obtained
commercially and used without further purification.
General Experimental Procedure for Synthesis of 1,4-
Enynes 3. To a 5-mL flask were added propargyl alcohol 1 (0.5
mmol), alkene 2 (0.6 mmol), 1,2-dichloroethane (DCE) (2.0 mL) and
Cu(OTf)2 (0.05 mmol) successively. The reaction mixture was stirred
at reflux and monitored periodically by TLC. Upon completion
(normally 10 min), DCE was removed under reduced pressure by an
aspirator, and then the residue was purified by flash chromatography
(hexane/ethyl acetate) on silica gel to afford 1,4-enynes 3.
1,1,3,5-Tetraphenylpent-1-en-4-yne3 (3ad). A yellow oil in
1
94% yield (174 mg, 0.47 mmol); H NMR (500 MHz, CDCl3) δ
7.62−7.58 (m, 2H), 7.57−7.53 (m, 4H), 7.50−7.43 (m, 5H), 7.42−
7.33 (m, 9H), 6.36 (d, J = 10.1 Hz, 1H), 4.87 (d, J = 10.1 Hz, 1H). 13C
NMR (125 MHz, CDCl3) δ 141.91, 141.87, 140.8, 139.3, 131.9, 130.1,
128.8, 128.7, 128.6, 128.4, 128.3, 128.1, 127.7, 127.64, 127.56, 127.0,
123.8, 120.0, 89.9, 84.2, 38.0. HRAPCIMS calcd for C29H23 (M + H)+
371.1800; found 371.1778.
(E)-1,3,5-Triphenylpent-1-en-4-yne9 (3aa). A pale yellow oil in
1
90% yield (132 mg, 0.45 mmol); H NMR (500 MHz, CDCl3) δ
(E)-1-(1,5-Diphenylpent-1-en-4-yn-3-yl)-4-fluorobenzene
(3ca). A yellow oil in 84% yield (131 mg, 0.42 mmol); 1H NMR (500
MHz, CDCl3) δ 7.55−7.52 (m, 2H), 7.48−7.44 (m, 2H), 7.42 (d, J =
7.5 Hz, 2H), 7.37−7.31 (m, 6H), 7.08−7.04 (m, 2H), 6.79 (d, J = 15.6
Hz, 1H), 6.34 (dd, J = 15.6 and 6.6 Hz, 1H), 4.76 (d, J = 6.6 Hz, 1H).
13C NMR (125 MHz, CDCl3) δ 162.9 and 160.9, 136.7, 131.7, 130.6,
7.56−7.51 (m, 4H), 7.43−7.39 (m, 4H), 7.39−7.32 (m, 6H), 7.29−
7.27 (m, 1H), 6.84 (d, J = 15.6 Hz, 1H), 6.40 (dd, J = 15.6 and 6.5 Hz,
1H), 4.81 (d, J = 6.5 Hz, 1H). 13C NMR (125 MHz, CDCl3) δ 140.3,
136.8, 131.7, 130.4, 129.6, 128.7, 128.5, 128.2, 128.0, 127.7, 127.5,
127.1, 126.5, 123.4, 88.8, 85.4, 41.2. HRAPCIMS calcd for C23H19 (M
+ H)+ 295.1487; found 295.1485.
(E)-1-Bromo-4-(3,5-diphenylpent-en-4-ynyl)benzene (3ab).
A yellow oil in 84% yield (156 mg, 0.42 mmol); 1H NMR (500
MHz, CDCl3) δ 7.55−7.51 (m, 4H), 7.48−7.39 (m, 5H), 7.38−7.32
(m, 4H), 7.28−7.25 (m, 1H), 6.75 (d, J = 15.7 Hz, 1H), 6.37 (dd, J =
15.7 and 6.5 Hz, 1H), 4.78 (d, J = 6.5 Hz, 1H). 13C NMR (125 MHz,
CDCl3) δ 140.0, 135.7, 131.7, 131.6, 130.4, 129.2, 128.74, 128.65,
128.2, 128.0, 127.7, 127.2, 123.3, 121.2, 88.5, 85.6, 41.2. HRAPCIMS
calcd for C23H16Br (M + H)+ 371.0435, 373.0415; found 371.0433,
373.0413.
129.34, 129.28, 129.2, 128.5, 128.3, 128.1, 127.6, 126.5, 123.3, 115.6
and 115.4, 88.6, 85.6, 40.5. HRAPCIMS calcd for C23H16F (M − H)+
311.1236; found 311.1216.
(E)-4-(3-(4-Fluorophenyl)-5-phenylpent-1-en-4-ynyl)phenyl
1
Acetate (3cc). A yellow oil in 85% yield (157 mg, 0.43 mmol); H
NMR (500 MHz, CDCl3) δ 7.52−7.48 (m, 2H), 7.47−7.43 (m, 2H),
7.42−7.39 (m, 2H), 7.35−7.31 (m, 3H), 7.10−7.02 (m, 4H), 6.75 (dd,
J = 15.7 and 1.4 Hz, 1H), 6.27 (dd, J = 15.7 and 6.5 Hz, 1H), 4.73 (d, J
= 6.5 Hz, 1H), 2.29 (s, 3H). 13C NMR (125 MHz, CDCl3) δ 169.4,
162.9 and 161.0, 150.1, 135.9, 134.5, 131.7, 129.6, 129.3, 129.2, 128.3,
128.1, 127.5, 123.2, 121.7, 115.6 and 115.4, 88.4, 85.6, 40.4, 21.1.
HRAPCIMS calcd for C25H20FO2 (M + H)+ 371.1447; found
371.1436.
(E)-4-(3,5-Diphenyipent-1-en-4-ynyl)phenyl Acetate (3ac). A
1
yellow oil in 92% yield (161 mg, 0.46 mmol); H NMR (500 MHz,
CDCl3) δ 7.58−7.55 (m, 4H), 7.46−7.41 (m, 4H), 7.40−7.32 (m,
4H), 7.10 (d, J = 8.5 Hz, 2H), 6.82 (d, J = 15.6 Hz, 1H), 6.36 (dd, J =
15.6 and 6.5 Hz, 1H), 4.81 (d, J = 6.5 Hz, 1H), 2.32 (s, 3H). 13C NMR
(125 MHz, CDCl3) δ 169.3, 149.9, 140.1, 134.5, 131.6, 129.8, 129.4,
128.7, 128.2, 128.0, 127.6, 127.4, 127.1, 123.3, 121.6, 88.7, 85.4, 41.1,
1-Fluoro-4-(1,1,5-triphenylpent-1-en-4-yn-3-yl)benzene
(3cd). A yellow oil in 87% yield (169 mg, 0.44 mmol); 1H NMR (500
MHz, CDCl3) δ 7.60−7.57 (m, 2H), 7.55−7.51 (m, 2H), 7.50−7.44
2744
dx.doi.org/10.1021/jo3026803 | J. Org. Chem. 2013, 78, 2742−2745

The Journal of Organic Chemistry
Note
(m, 5H), 7.42−7.37 (m, 3H), 7.36−7.31 (m, 5H), 7.17−7.06 (m, 2H),
6.31 (d, J = 10.1 Hz, 1H), 4.82(d, J = 10.1 Hz, 1H). 13C NMR (125
MHz, CDCl3) δ 162.9 and 161.0, 142.1, 141.7, 139.2, 136.5, 131.9,
130.0, 129.1, 129.0, 128.7, 128.4, 128.3, 128.2, 127.8, 127.7, 127.7,
123.6, 115.6 and 115.4, 89.7, 84.3, 37.3. HRAPCIMS calcd for
C29H22F (M + H)+ 389.1706; found 389.1688.
ASSOCIATED CONTENT
* Supporting Information
Spectral data for all products. This material is available free of
charge via the Internet at http://pubs.acs.org.
■
S
AUTHOR INFORMATION
Corresponding Author
*E-mail: panym2004@yahoo.com.cn; zhangye81@126.com.
Notes
■
(E)-1-(3,5-Diphenylpent-1-en-4-ynyl)-4-methoxybenzene
(3ae). A yellow oil in 94% yield (152 mg, 0.47 mmol); 1H NMR (500
MHz, CDCl3) δ 7.54−7.49 (m, 4H), 7.37−7.34 (m, 3H), 7.35−7.31
(m, 4H), 7.31−7.27 (m, 1H), 6.86 (d, J = 8.8 Hz, 2H), 6.73 (d, J =
15.6 Hz, 1H), 6.22 (dd, J = 15.6 and 6.6 Hz, 1H), 4.75 (d, J = 6.6 Hz,
1H), 3.81 (s, 3H). 13C NMR (125 MHz, CDCl3) δ 159.1, 140.5,
131.7, 129.8, 129.6, 128.7, 128.2, 128.0, 127.70, 127.65, 127.5, 127.0,
123.5, 113.9, 89.0, 85.2, 55.3, 41.2. HRAPCIMS calcd for C24H21O (M
+ H)+ 325.1592; found 325.1592.
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
We thank the project 973 (2011CB512005), the National
Natural Science Foundation of China (41206077 and
81260472), and Guangxi Natural Science Foundation of
China (2012GXNSFAA053027, 2011GXNSFD018010, and
2010GXNSFF013001) for financial support.
(E)-1,3-Diphenylpent-1-en-4-yne10 (3da). A yellow oil in 80%
yield (87 mg, 0.40 mmol); 1H NMR (500 MHz, CDCl3) δ 7.51−7.47
(m, 2H), 7.42−7.38 (m, 4H), 7.35−7.31 (m, 4H), 6.81 (d, J = 15.7
Hz, 1H), 6.33−6.29 (m, 1H), 4.61 (d, J = 6.4 Hz, 1H), 2.55 (s, 1H).
13C NMR (125 MHz, CDCl3) δ 139.7, 136.6, 130.6, 128.9, 128.7,
REFERENCES
128.5, 127.6, 127.5, 127.2, 126.5, 83.3, 73.3, 40.3. HRAPCIMS calcd
■
for C17H13 (M − H)+217.1017; found 217.1010.
(1) For selected examples, see: (a) Trost, B. M.; McIntosh, M. C. J.
Am. Chem. Soc. 1995, 117, 7255. (b) Trost, B. M.; Sorum, M. T.;
Chan, C.; Harms, A. E.; Ruhter, G. J. Am. Chem. Soc. 1997, 119, 698.
2-(1,1,5-Triphenylpent-1-en-4-yn-3-yl)thiophene3 (3ed). A
1
yellow oil in 93% yield (175 mg, 0.47 mmol); H NMR (500 MHz,
̈
CDCl3) δ 7.59−7.54 (m, 2H), 7.53−7.48 (m, 2H), 7.47−7.42 (m,
3H), 7.41−7.32 (m, 8H), 7.28 (dd, J = 5.1 and 1.2 Hz, 1H), 7.14
(m,1H), 7.04 (dd, J = 5.1 and 3.5 Hz, 1H), 6.38 (d, J = 10.0 Hz, 1H),
5.00 (dd, J = 10.0 and 1.0 Hz, 1H). 13C NMR (125 MHz, CDCl3) δ
144.7, 142.2, 141.5, 138.7, 131.7, 129.8, 128.5, 128.19, 128.17, 128.1,
127.7, 127.6, 127.4, 126.9, 124.52, 124.45, 123.2, 89.1, 83.4, 33.6.
HRAPCIMS calcd for C27H21S (M + H)+377.1364; found 377.1357.
(E)-1,3-Diphenylundec-1-en-4-yne (3fa). A yellow oil in 90%
yield (136 mg, 0.45 mmol); 1H NMR (500 MHz, CDCl3) δ 7.46−7.43
(m, 2H), 7.42−7.35 (m, 4H), 7.32−7.29 (m, 3H), 7.24 (m, 1H), 6.75
(d, J = 15.6 Hz, 1H), 6.30 (dd, J = 15.6 and 6.5 Hz, 1H), 4.55 (d, J =
6.5 Hz, 1H), 2.33 (td, J = 7.1 and 2.2 Hz, 2H), 1.61−1.58(m, 2H),
1.52−1.45 (m, 2H), 1.40−1.31 (m, 4H), 0.94 (t, J = 6.9 Hz, 3H). 13C
NMR (125 MHz, CDCl3) δ 141.0, 137.0, 130.5, 129.8, 128.5, 128.4,
127.6, 127.3, 126.8, 126.4, 85.8, 79.1, 40.7, 31.3, 28.9, 28.6, 22.6, 18.9,
14.1. HRAPCIMS calcd for C23H25 (M + H)+ 301.1956; found
301.1948.
1,1,3-Triphenylundec-1-en-4-yne (3fd). A yellow oil in 93%
yield (176 mg, 0.47 mmol); 1H NMR (500 MHz, CDCl3) δ 7.49−7.46
(m, 4H), 7.45−7.42 (m, 3H), 7.41−7.37 (m, 2H), 7.33−7.28 (m, 6H),
6.23 (d, J = 10.2 Hz, 1H), 4.59 (d, J = 10.2 Hz, 1H), 2.36 (td, J = 7.1
and 2.3 Hz, 2H), 1.65−1.61 (m, 2H), 1.53−1.49 (m, 2H), 1.41−1.38
(m, 4H), 0.99 (t, J = 7.0 Hz, 3H). 13C NMR (125 MHz, CDCl3) δ
141.9, 141.3, 140.9, 139.3, 129.9, 129.5, 128.4, 128.4, 128.1, 127.5,
127.4, 127.34, 127.28, 126.6, 84.3, 80.1, 37.3, 31.3, 28.9, 28.5, 22.6,
19.0, 14.1. HRAPCIMS calcd for C29H31 (M + H)+ 379.2426; found
379.2423.
(c) Frantz, D. E.; Fassler, R.; Carreira, E. M. J. Am. Chem. Soc. 1999,
̈
121, 11245. (d) Trost, B. M.; Frontier, A. J. J. Am. Chem. Soc. 2000,
122, 11727. (e) Fischer, C.; Carreira, E. M. Org. Lett. 2001, 3, 4319.
(f) Knopfel, T. F.; Carreira, E. M. J. Am. Chem. Soc. 2003, 125, 6054.
̈
(g) Fischer, C.; Carreira, E. M. Org. Lett. 2004, 6, 1497. (h) Nishimura,
T.; Washitake, Y.; Nishiguchi, Y.; Maeda, Y.; Uemura, S. Chem.
Commun. 2004, 1312. (i) Nishimura, T.; Washitake, Y.; Uemura, S.
Adv. Synth. Catal. 2007, 349, 2563. (j) Zhou, L.; Chen, L.; Skouta, R.;
Jiang, H.-F.; Li, C.-J. Org. Biomol. Chem. 2008, 6, 2969. (k) Ren, K.; Li,
P.; Wang, L.; Zhang, X. Tetrahedron 2011, 67, 2753. (l) Suzuki, Y.;
Naoe, S.; Oishi, S.; Fujii, N.; Ohno, H. Org. Lett. 2012, 14, 326.
(m) Xu, Y.-L.; Pan, Y.-M.; Liu, P.; Wang, H.-S.; Tian, X.-Y.; Su, G.-F. J.
Org. Chem. 2012, 77, 3557. (n) Liu, P.; Pan, Y.-M.; Xu, Y.-L.; Wang,
H.-S. Org. Biomol. Chem. 2012, 10, 4696.
(2) For selected examples, see: (a) Pan, Y.-M.; Zhao, S.-Y.; Ji, W.-H.;
Zhan, Z.-P. J. Comb. Chem. 2009, 11, 105. (b) Zhan, Z.-P.; Yu, J.-L.;
Liu, H.-J.; Cui, Y.-Y.; Yang, R.-F.; Yang, W.-Z.; Li, J.-P. J. Org. Chem.
2006, 71, 8298. (c) Pan, Y.-M.; Zheng, F.-J.; Lin, H.-X.; Zhan, Z.-P. J.
Org. Chem. 2009, 74, 3148.
(3) Peng, S.-Y.; Wang, L.; Wang, J. Org. Biomol. Chem. 2012, 10, 225.
(4) Wu, Q.; Liu, P.; Pan, Y.-M.; Xu, Y.-L.; Wang, H.-S. RSC Adv.
2012, 2, 10167.
(5) (a) Li, X.-X.; Huang, S.-Y.; Schienebeck, C.-M.; Shu, D.-X.; Tang,
W.-P. Org. Lett. 2012, 14, 1484. (b) Sato, T.; Onuma, T.; Nakamura,
I.; Terada, M. Org. Lett. 2011, 13, 4992.
(6) (a) Muller, K.; Faeh, C.; Diederich, F. Science 2007, 317, 1881.
(b) Belisle, J. Science 1981, 212, 1509. (c) Shimizu, M.; Hiyama, T.
Angew. Chem., Int. Ed. 2005, 44, 214.
(7) Laali and coworkers also have reported that metallic triflates
could promote self- or crossedcondensation of propargylic alcohols to
synthesize a variety of bis-propargylic ethers in imidazolium ionic
liquids. See: Aridoss, G.; Sarca, V.-D.; Ponder, J.-F., Jr; Crowe, J.; Laali,
K.-K. Org. Biomol. Chem. 2011, 9, 2518.
(8) (a) Wang, T.; Chen, X.-L.; Chen, L.; Zhan, Z.-P. Org. Lett. 2011,
13, 3324. (b) Reference 2. (c) Georgy, M.; Boucard, V.; Campagne, J.-
M. J. Am. Chem. Soc. 2005, 127, 14180. (d) Reference 3. (e)
Reference 4.
(E)-(3,5-Diphenylpent-4-en-1-ynyl)trimethylsilane (3ga). A
1
yellow oil in 94% yield (136 mg, 0.47 mmol); H NMR (500 MHz,
CDCl3) δ 7.47−7.43 (m, 2H), 7.40−7.37 (m, 4H), 7.36−7.31 (m,
4H), 6.74 (d, J = 15.7 Hz, 1H), 6.29 (dd, J = 15.7 and 6.6 Hz, 1H),
4.60 (d, J = 6.6 Hz, 1H), 0.28 (s, 9H). 13C NMR (125 MHz, CDCl3) δ
139.9, 136.8, 130.4, 129.5, 128.6, 128.5, 127.7, 127.5, 127.0, 126.5,
89.7, 73.3, 41.6, 0.1. HRAPCIMS calcd for C20H21Si (M − H)+
289.1413; found 289.1413.
3-(1,3-Diphenylprop-2-ynyloxy)-1,3-diphenylprop-1-yne7
(4aa). A colorless oil in 81% yield (161 mg, 0.41 mmol); NMR shows
(9) Paz, T.; Alejandro, B.; Carmen, N. J. Org. Chem. 2012, 77, 7344.
(10) Yue, H.-L.; Wei, W.; Li, M.-M.; Yang, Y.-R.; Ji, J.-X. Adv. Synth.
Catal. 2011, 353, 3139.
1
the presence of two geometrical isomers in a 1:0.64 ratio. H NMR
(500 MHz, CDCl3) δ 7.76−7.74 (m, 2H), 7.71−7.69 (m, 2H), 7.61−
7.60 (m, 2H), 7.55−7.53 (m, 2H), 7.49−7.47 (m, 2H), 7.46−7.43 (m,
5H), 7.41−7.38 (m, 5H), 7.37−7.35 (m, 2H), 6.05 (s, 2H), 5.66 (s,
2H). 13C NMR (125 MHz, CDCl3) δ138.5, 138.9, 131.9, 131.8, 128.6,
128.5, 128.4, 128.4, 128.3, 128.2, 128.1, 127.9, 127.7, 127.5, 122.51,
122.46, 88.1, 87.8, 87.1, 86.7, 70.2, 69.7. EI-MS (m/z) 399 [M + H+].
2745
dx.doi.org/10.1021/jo3026803 | J. Org. Chem. 2013, 78, 2742−2745