Highly regio- and stereoselective synthesis of 1,3-enynes from unactivated ethylenes via palladium-catalyzed cross-coupling

Article abstract of DOI:10.1016/j.tetlet.2011.07.092

An efficient procedure for regio- and stereoselective synthesis of a series of conjugated enynes by a simple Pd-catalyzed cross-coupling reaction of unactivated ethylenes and ethynyl bromide has been developed. The reaction proceeds smoothly in DMF to give the corresponding products in good to excellent yields. The protocol can tolerate a broad range of functional groups on the substrates.

Full text of DOI:10.1016/j.tetlet.2011.07.092

Tetrahedron Letters 52 (2011) 5736–5739
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Tetrahedron Letters
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Highly regio- and stereoselective synthesis of 1,3-enynes from
unactivated ethylenes via palladium-catalyzed cross-coupling
Yanmei Wen a,b, Azhong Wang a, Huanfeng Jiang a, , Shifa Zhu a, Liangbin Huang a
⇑
a School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou 510640, China
b College of Science, Guangdong Ocean University, Zhanjiang 524088, China
a r t i c l e i n f o
a b s t r a c t
Article history:
An efficient procedure for regio- and stereoselective synthesis of a series of conjugated enynes by a sim-
ple Pd-catalyzed cross-coupling reaction of unactivated ethylenes and ethynyl bromide has been devel-
oped. The reaction proceeds smoothly in DMF to give the corresponding products in good to excellent
yields. The protocol can tolerate a broad range of functional groups on the substrates.
Ó 2011 Elsevier Ltd. All rights reserved.
Received 8 May 2011
Revised 19 July 2011
Accepted 21 July 2011
Available online 10 August 2011
1,3-Enyne moiety is an important unit often found in many nat-
urally occurring and biologically active compounds1 which include
hachijodine G,2 a cytotoxic sponge alkaloid, terbinafine,3 a potent
present the first example of a facile synthesis of the 1,3-enynes
from the simple 1-bromoalkyne with a wide range of alkenes in
a highly regio- and stereoselective manner.
drug for superficial fungal infections, neocarzinostatin,4 and cali-
To optimize the reaction protocol we chose the cross-coupling
of styrene and phenylethynyl bromide as the model reaction. As
shown in Table 1, the reaction did not proceed at 40 °C (Table 1, en-
try 1). Enhancing the temperature to 60 °C, the product 1,4-diphe-
nyl-but-1-en-3-yne can be formed in 86% yield (Table 1, entry 2).
At 80 °C, the reaction afforded the product in 92% yield with good
E:Z selectivity (E:Z ratio = 93:7) (Table 1, entry 3). Further increas-
ing the temperature to 100 °C gave the desired product in a lower
stereoselectivity (Table 1, entry 4). Both Pd(OAc)2 and PdCl2
showed good catalytic activities (Table 1, entries 3 and 10).
Pd2(dba)3 gave lower yield of the product (Table 1, entry 14). Inter-
estingly, with 10% Pd/C as the catalyst and K2CO3 as the base, the
desired product was not obtained. However, with KOAc as the base,
the yield was improved to 80% (Table 1, entries 11 and 12). The
reaction without palladium did not proceed at all (entry 13).
5
chemicin c1
,
an effective antitumor antibiotic. Furthermore, 1,3-
enynes are also very useful synthetic intermediates. Typically, they
are valuable precursors for polysubstituted benzenes,6 conjugated
dienes,7 and polyenes.8 For these reasons, the design and synthesis
of such compounds containing an enyne moiety have received con-
siderable attention in organic synthesis and have been extensively
studied. However, only a limited number of procedures for the syn-
thesis of conjugated enynes have been developed.
The Sonogashira cross-coupling reaction for the synthesis of
enynes between a vinyl halide and a terminal alkyne or organome-
tallic alkyne using Pd–Cu catalyst has become an indispensable
and powerful tool for the synthesis of enynes.9 Recently, Yang
and co-workers discovered a copper-catalyzed or iron-catalyzed
coupling of alkynes or alkyne derivatives with vinyl halides.9f–h,10
Moreover, Nishimura and co-workers also reported an elegant pro-
tocol of the palladium-catalyzed oxidative alkynylation of alkenes
using tert-propargylic alcohols as alkynylation reagents.11 How-
ever, limited attention has been turned to another alternative
cross-coupling reaction between a terminal alkene and a halo-
alkyne which is highly valuable synthon and widely used in syn-
thetic organic chemistry.12 In 1987, Jeffery’s group developed the
synthesis of conjugated enynes through the coupling of active al-
kenes with iodoalkynes by using palladium(II) catalyst under
solid–liquid phase-transfer conditions. In this protocol, only acrylic
esters and nitriles were subjected to the coupling with iodoalky-
nes.13 To the best of our knowledge, no example of Pd-catalyzed
cross-coupling of 1-bromoalkynes with terminal ‘unactivated’ eth-
ylenes to enynes has been reported Scheme 1. Herein, we wish to
Approach I
Pd/Cu/L
+
R1
R2
R1
(1)
X
R2
or Cu
X=Br, I or OTf
Approach II
R1
Pd
+
+
GWE
Aryl
I
R1
(2)
(3)
R2
This work
R
Pd
Br
R
Aryl
⇑
Corresponding author. Tel./fax: +86 20 87112906.
E-mail address: jianghf@scut.edu.cn (H. Jiang).
Scheme 1. General approaches for enynes.
0040-4039/$ - see front matter Ó 2011 Elsevier Ltd. All rights reserved.
doi:10.1016/j.tetlet.2011.07.092

Y. Wen et al. / Tetrahedron Letters 52 (2011) 5736–5739
5737
Table 1
en-3-yne in the reaction when base such as Cs2CO3 or Et3N were
used instead of K2CO3 (Table 1, entries 6 and 8). The suitable
amount of K2CO3 is 2.5 equiv (Table 1, entries 3 and 17). The best
molar ratio of phenylethynyl bromide to styrene is 1:10 (Table 1,
entries 3, 15 and 16). On the basis of the results above, we decided
to use 5 mol % Pd(OAc)2 as the catalyst and 2.5 equiv of K2CO3 as
the base in DMF at 80 °C for the standard protocol to synthesize
1,3-enynes.
With the optimized reaction conditions in hand, we then
started to study the scope of the reaction.14 Firstly, we examined
the efficiency of coupling a variety of ethylenes to phenylethynyl
bromide 1a. As shown in Scheme 2, this transformation was highly
efficient for a broad scope of substrates in good to excellent yields,
wherein various functional groups, including halide (3af, 3ag, 3ah),
nitro (3ai), methoxyl (3ae) and alkyl (3ac, 3ad) could be tolerated.
The bromoaryl group was tolerated in this transformation and
therefore available for further functionalization of the product at
Optimization of experimental conditions for the formation of 1,3-enynesa
Entry
Catalyst
Base
Temp. (°C)
Yieldb (%)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15c
16d
17e
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
PdCl2
10%Pd/C
10%Pd/C
—
Pd2(dba)3
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
K2CO3
K2CO3
K2CO3
K2CO3
Na2CO3
Cs2CO3
KOAc
NEt3
40
60
80
100
80
80
80
80
80
80
80
80
80
80
80
80
80
0
86
92 (E/Z 93:7)⁄
90 (E/Z 85:15)
82
0
73
0
0
80
0
80
0
16
70
25
30
—
K2CO3
K2CO3
KOAc
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
the C–Br bond (3ah). It is noteworthy that
a-methylstyrene was
a
Reaction conditions: 1.0 mmol phenylethynyl bromide, 10.0 mmol styrene,
also suitable substrate under standard coupling conditions, afford-
ing the corresponding 1,3-enyne products in moderate yields (3aj).
Furthermore, heterocyclic ethylenes such as a pyridine moiety
(3ak) were also compatible substrates with this protocol. However,
no desired product was detected when 1,1-diphenylethene was
used as the substrate; and alkenes, such as 1-octene, were treated
with phenylethynyl bromide only afforded a mixture of products.
The apparent lack of reactivity for this substrate is still unclear at
this stage, and investigations to overcome this issue are ongoing.
Next, we turned our attention to the cross-coupling of styrene
2a with various readily accessible bromoalkynes (Scheme 3). Both
aryl- and alkyl-substituted ethynyl bromides are good substrates
5 mol % Pd(II) catalyst, 2.5 equiv K2CO3, DMF, 80 °C, 2 h.
b
Determined by GC.
The molar ratio of phenylethynyl bromide to styrene is 1:8.
The molar ratio of phenylethynyl bromide to styrene is 1:5.
1.0 equiv K2CO3.
c
d
e
*
The optimized reaction condition.
Using Pd(OAc)2 as the catalyst we then screened a variety of
bases for the cross-coupling of styrene and phenylethynyl bromide
in DMF at 80 °C for 2 h. Base had an important influence on the
reaction. Na2CO3 and KOAc afforded similar results in this reaction
(Table 1, entries 5 and 7). We did not observe 1,4-diphenyl-but-1-
5 mol % Pd(OAc)2
2.5 equiv K2CO3
Aryl
+
Br
Aryl
DMF, 80 oC, 2 h
1a
2
3
3aa, 90% (E/Z=93:7)
3ad, 82% (E/Z=93:7)
3ab, 88% (E/Z=93:7)
3ae, 87% (E/Z=96:4)
3ac, 91% (E/Z=91:9)
3af, 75% (E/Z =97:3)
F
OCH3
NO2
F
F
Br
F
F
F
3ai, 72 %(only E isomer)
3ah, 78% (E/Z=75:25)
3ag, 80%(only E isomer)
N
3aj, 62%(only E isomer)
3ak, 95%(only E isomer)
Scheme 2. Palladium-catalyzed cross-coupling of various ethylenes with 1a using the standard protocol. aReactions were carried out using 1.0 mmol phenylethynyl bromide,
10.0 mmol styrene, 5 mol % Pd(II) catalyst, 2.5 equiv K2CO3, DMF, 80 °C. bIsolated yields.

5738
Y. Wen et al. / Tetrahedron Letters 52 (2011) 5736–5739
5 mol % Pd(OAc)2
2.5 equiv K2CO3
DMF, 80 oC, 2 h
+
Br
R
R
2a
1
3
O
3da, 92%, (E/Z=91:9)
3ga, 63 %, (E/Z=96:4)
3ca, 88%, (E/Z=96:4)
3ba, 84%, (E/Z=98:2)
Br
3fa, 74%, (E/Z=85:15)
3ea, 41%, (E/Z=95:5)
OH
3ia, 56%, (E/Z=93:7)
3ha, 69%, (E/Z=94:6)
Scheme 3. Palladium-catalyzed cross-coupling of various alkynyl bromide with 2a using the standard protocol. aReactions were carried out using 1.0 mmol phenylethynyl
bromide, 10.0 mmol styrene, 5 mol % Pd(II) catalyst, 2.5 equiv K2CO3, DMF, 80 °C. bIsolated yields.
R1
not reported earlier. The use of these precursors for the synthesis of
conjugated enynes from bromoalkynes and internal alkenes is in
progress and will be reported in due course.
Br
1
oxidative addition
+
Pd (0)
R2
R1
R1
Acknowledgments
Pd Br
A
3
base
We thank the National Natural Science Foundation of China
(20932002), National Basic Research Program of China (973 Pro-
gram) (2011CB808600), Doctoral Fund of Ministry of Education
of China (20090172110014) and Guangdong Natural Science Foun-
dation (10351064101000000 and 8451064101000236) for finan-
cial support.
R2
2
R1
cis-elimination
PdBr
cis-insertion
R2
H
B
Scheme 4. Proposed mechanism.
Supplementary data
for this system. Bromoalkynes possessing electron-donating
groups on the aromatic ring afforded the product 3ba, 3ca, 3da,
3ea and 3fa in 84%, 88%, 92%, 70% and 74% isolated yields, respec-
tively. In comparison, bromoalkynes possessing electron-with-
drawing groups gave the product 3ga in lower yield of 63%.
Alkynyl bromides such as 3-hydroxy-3,5-dimethylhexynyl bro-
mide, octynyl bromide can undergo the same transformation in
moderate yields (3ha, 3ia).
We proposed the following reaction mechanism (Scheme 4): (1)
oxidative addition of the 1-bromoalkyne 1 to Pd(0) giving an alky-
nylpalladium(II) intermediate A; (2) a Heck cross-coupling with al-
kene 2 and intermediate B was produced in this step; (3) a b-H
elimination produced the target product 3 with simultaneous
regeneration of the Pd(0) catalyst.
In summary, we developed an efficient and general catalytic sys-
tem for the cross-coupling reaction of a wide range of unactivated
aryl alkenes and bromoalkynes in the absence of any stabilizing li-
gands or special additives. The process is regio- and stereoselective,
and provides good access to a series of functionalized 1,3-enynes in
good to excellent yields. Moreover, the reaction tolerates several
functional groups on both coupling partners. To the best of our
knowledge, this strategy for the stereoselective synthesis of conju-
gated enynes from bromoalkynes involving palladium is novel and
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.tetlet.2011.07.092.
References and notes
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White solid, mp: 98–99 °C, IR (KBr): 1608, 1520, 1495, 996, 951, 757, 690; 1H
NMR (400 MHz, CDCl3)
d 7.51–7.47 (m, 2H), 7.37–7.34 (m, 3H), 6.93 (d,
J = 16.8 Hz, 1H), 6.73 (d, J = 16.4 Hz, 1H); 13C NMR (100 MHz, CDCl3) d 142.97,
132.47, 131.73, 128.87, 128.46, 124.98, 124.96, 122.67, 117.34, 117.27, 107.55,
95.08, 88.19 ppm; HRMS EI (m/z): calcd for
C16H7F5, 294.0468; found,
294.0463. (E)-1-(4-Bromophenyl)-4-phenyl-but-1-en-3-yne (3ah). White
solid, mp: 93–94 °C, IR (KBr): 2925, 1597, 1507, 1441, 1230, 956, 816, 756,
691; 1H NMR (400 MHz, CDCl3) d 7.47–7.28 (m, 9H), 6.96 (d, J = 16.4 Hz, 0.89H),
6.37 (d, J = 16.0 Hz, 0.89H); 13C NMR (100 MHz, CDCl3) d 139.91, 131.93,
131.56, 128.41, 127.75, 126.76, 123.25, 122.54, 113.98, 108.96, 92.43,
88.59 ppm; HRMS EI (m/z): calcd for C16H11Br, 282.0044; found, 282.0040.
(E)-1-(3-Nitrophenyl)-4-phenyl-but-1-en-3-yne (3ai). Yellow solid, mp: 86–
87 °C, IR (KBr): 2923, 1525, 1347, 947, 753, 685; 1H NMR (400 MHz, CDCl3) d
8.28 (s, 1H), 8.14 (d, J = 8.0 Hz, 1H), 7.72 (d, J = 8.0 Hz, 1H), 7.54–7.47 (m, 3H),
7.35 (t, J = 3.2 Hz, 3H), 7.06 (d, J = 16.4 Hz, 1H), 6.53 (d, J = 16.0 Hz, 1H); 13C
NMR (100 MHz, CDCl3)
d 148.73, 138.36, 138.09, 131.88, 131.66, 129.72,
10. (a) Liu, Y.; Yang, J.; Bao, W. Eur. J. Org. Chem. 2009, 5317–5320; (b) Xie, X.; Xu,
X.; Li, H.; Xu, X.; Yang, J. Adv. Synth. Catal. 2009, 351, 1263–1267.
128.66, 128.44, 122.93, 122.90, 120.78, 111.63, 93.71, 87.86 ppm; HRMS EI (m/
z): calcd for C16H11NO2, 249.0790; found, 247.0783. (E)-1-Methyl-1-phenyl-4-
phenyl-but-1-en-3-yne (3aj). White solid, mp: 100–102 °C, IR (KBr): 2924,
11. Nishimura, T.; Araki, H.; Maeda, Y.; Uemura, S. Org. Lett. 2003, 5, 2997–2999.
12. For selective examples, see: (a) Negishi, E.-I.; Qian, M. X.; Zeng, F. X.; Anastasia,
L.; Babinski, D. Org. Lett. 2003, 5, 1597–1600; (b) Seregin, I. V.; Ryabova, V.;
Gevorgyan, V. J. Am. Chem. Soc. 2007, 129, 7742–7743; (c) Trofimov, A.;
Chernyak, N.; Gevorgyan, V. J. Am. Chem. Soc. 2008, 130, 13538–13539; (d)
Frederick, M. O.; Mulder, J. A.; Tracey, M. R.; Hsung, R. P.; Huang, J.; Kurtz, K. C.
M.; Shen, L.; Douglas, C. J. J. Am. Chem. Soc. 2003, 125, 2368–2369; (e) Tobisu,
M.; Ano, Y.; Chatani, N. Org. Lett. 2009, 11, 3250–3252; (f) Matsuyama, N.;
Hirano, K.; Satoh, T.; Miura, M. Org. Lett. 2009, 11, 4156–4159; (g) Yao, B.;
Liang, Z.; Niu, T.; Zhang, Y. J. Org. Chem. 2009, 74, 4630–4633; (h) Laroche, C.; Li,
J.; Freyer, M. W.; Kerwin, S. M. J. Org. Chem. 2008, 73, 6462–6465; (i) Morishita,
T.; Yoshida, H.; Ohshita, J. Chem. Commun. 2010, 640–642; (j) Li, Y.; Liu, X.;
Jiang, H.; Feng, Z. Angew. Chem., Int. Ed. 2010, 49, 3338–3341; (k) Li, Y.; Liu, X.;
Jiang, H.; Liu, B.; Chen, Z.; Zhou, P. Angew. Chem., Int. Ed. 2011, 50, 6341–6345.
13. Jeffery, T. Synthesis 1987, 70–71.
1442, 951, 750, 687 cmÀ1 1H NMR (400 MHz, CDCl3) d 7.52–7.33 (m, 10H),
;
6.14 (s, 1H), 2.43 (s, 3H); 13C NMR (100 MHz, CDCl3) d 148.36, 140.89, 131.37,
128.46, 128.35, 128.14, 128.03, 125.48, 123.77, 106.59, 95.27, 88.23,
18.72 ppm; MS (EI, 70 eV) m/z (%): 218 (M+, 100), 202 (88), 115 (17). (E)-2-
(4-Phenylbut-1-en-3-ynyl) pyridine (3ak). Blue oil; IR (KBr): 3053, 2925, 1615,
1581, 1467, 1432, 1254, 1150, 954, 757, 690; 1H NMR (400 MHz, CDCl3) d 8.59
(d, J = 4.4 Hz, 1H), 7.65 (t, J = 8.0 Hz, 1H), 7.51–7.48 (m, 2H), 7.35–7.33 (m, 3H),
7.27 (d, J = 7.2 Hz, 1H), 7.19–7.16 (m, 1H), 7.07 (d, J = 16.0 Hz, 1H), 6.98 (d,
J = 16.0 Hz, 1H); 13C NMR (100 MHz, CDCl3) d 154.21, 149.74, 139.89, 136.66,
131.70, 128.45, 128.37, 123.23, 122.93, 122.31, 112.81, 93.73, 88.68 ppm;
HRMS EI (m/z): calcd for C15H11N, 205.0891; found, 205.0887. (E)-1-Phenyl-4-
(4-methylphenyl)-but-1-en-3-yne (3ba). White solid, mp: 86–88 °C, IR (KBr):
3028, 2924, 1913, 1505, 1446, 1074, 956, 818, 751, 690, 533; 1H NMR
(400 MHz, CDCl3)
J = 16.4 Hz, 0.90H), 6.38 (d, J = 16.4 Hz, 0.90H), 2.36 (s, 3H); 13C NMR (100 MHz,
CDCl3) 140.89, 138.38, 136.46, 131.44, 129.15, 128.75, 128.54, 126.29,
120.36, 108.35, 92.02, 88.29, 21.53 ppm; HRMS EI (m/z): calcd for C17H14
d 7.43–7.24 (m, 7H), 7.14 (d, J = 8.0 Hz, 2H), 7.02 (d,
14. General procedure for palladium-catalyzed cross-coupling reaction of
unactivated ethylenes with ethynyl bromides. To the mixture of 5 mol %
Pd(II) catalyst, potassium carbonate (2.5 equiv), terminal ethylene (10 mmol)
and 1.5 mL N,N-dimethylformamide were added successively, stirred for 5 min
at the room temperature. Ethynyl bromide (1.0 mmol) in N,N-
dimethylformamide (0.5 mL) were added, then the mixture was stirred at
80 °C for 2 h. The solution was extracted with ethyl acetate (3 Â 15 mL), and
the combined extract was dried with anhydrous MgSO4. Solvent was removed,
and the residue was separated by column chromatography to give the pure
sample. (E)-1,4-Diphenyl-but-1-en-3-yne (3aa).9h Light yellow solid, mp: 97–
d
,
218.1096; found, 218.1091. (E)-1-Phenyl-4-(4-t-butylphenyl)-but-1-en-3-yne
(3ca). Yellow solid, mp: 105–107 °C, IR (KBr): 2963, 1598, 1501, 1448, 1267,
950, 834, 747, 690, 561; 1H NMR (400 MHz, CDCl3) d 7.43–7.24 (m, 9H), 7.03 (d,
J = 16.0 Hz, 0.82H), 6.40 (d, J = 16.4 Hz, 0.82H), 1.32 (s, 9H); 13C NMR (100 MHz,
CDCl3)
125.47, 125.39, 120.40, 108.39, 92.02, 88.29, 34.82, 31.20 ppm; HRMS EI (m/z):
calcd for 20H20 260.1565; found, 260.1561. (E)-1-Phenyl-4-(4-
d 151.51, 140.88, 136.46, 131.28, 128.75, 128.54, 128.30, 126.29,
C
,
98 °C, IR (KBr): 2924, 1442, 951, 750, 687 cmÀ1
;
1H NMR (400 MHz, CDCl3) d
methoxyphenyl)-but-1-en-3-yne (3da). Light yellow solid, mp: 91–92 °C, IR
(KBr): 2929, 2190, 1598, 1506, 1246, 1031, 950, 829, 746, 689; 1H NMR
(400 MHz, CDCl3) d 7.35–7.29 (m, 4H), 7.24–7.15 (m, 3H), 6.91 (d, J = 16.0 Hz,
0.92H), 6.78 (t, J = 8.8 Hz, 2H), 6.29 (d, J = 16.4 Hz, 0.92H), 3.72 (s, 3H); 13C NMR
(100 MHz, CDCl3) d 159.62, 140.47, 136.52, 133.00, 128.74, 128.28, 126.24,
115.56, 113.88, 108.43, 91.88, 87.67, 55.31 ppm; HRMS EI (m/z): calcd for
7.49 (d, J = 6.4 Hz, 2H), 7.44 (d, J = 7.2 Hz, 2H), 7.37–7.30 (m, 6H), 7.06 (d,
J = 16.4 Hz, 1H), 6.40 (d, J = 16.4 Hz, 1H); 13C NMR (100 MHz, CDCl3) d 141.29,
136.36, 131.54, 128.76, 128.65, 128.36, 128.21, 126.33, 123.43, 108.15, 91.76,
88.90 ppm; MS (EI, 70 eV) m/z (%): 204 (M+, 100), 101 (23), 89 (9). (E)-1-(2-
Naphthyl)-4-phenyl-but-1-en-3-yne (3ab). Yellow solid, mp: 107–109 °C IR
(KBr): 1438, 957, 814, 743, 690, 482; 1H NMR (400 MHz, CDCl3) d 7.78–7.68 (m,
7H), 7.54–7.42 (m, 5H), 7.13 (d, J = 16.0 Hz, 1H), 6.44 (d, J = 16.0 Hz, 1H); 13C
C17H14O, 234.1045; found, 234.1048. (E)-1-Phenyl-4-(3-methylphenyl)-but-1-
en-3-yne (3ea). Yellow solid, mp: 84–86 °C IR (KBr): 2924, 1485, 950, 782, 699;
1H NMR (400 MHz, CDCl3) d 7.44–7.27 (m, 7H), 7.24–7.12 (m, 2H), 7.04 (d,
J = 16.0 Hz, 0.93H), 6.39 (d, J = 16.0 Hz, 0.93H), 2.34 (s, 3H); 13C NMR (100 MHz,
NMR (100 MHz, CDCl3)
d 141.43, 133.89, 133.55, 131.64, 131.53, 128.54,
128.47, 128.31, 127.81, 127.07, 126.59, 126.47, 126.34, 123.54, 122.83, 108.48,
92.27, 89.23 ppm; HRMS EI (m/z): calcd for C20H14, 254.1096; found, 254.1091.
(E)-1-(2-Methylphenyl)-4-phenylbut-1-en-3-yne (3ac). Yellow oil; IR (KBr):
2924, 1595, 1485, 1032, 951, 751, 699; 1H NMR (400 MHz, CDCl3) d 7.49 (d,
J = 4.0 Hz, 3H), 7.33–7.31 (m, 3H), 7.22 (d, J = 15.2 Hz, 1H), 7.20–7.17 (m, 3H),
6.30 (d, J = 16.0 Hz, 1H), 2.40 (s, 3H); 13C NMR (100 MHz, CDCl3) d 139.07,
135.89, 135.30, 131.56, 130.60, 128.55, 128.39, 128.23, 126.28, 124.96, 123.43,
109.11, 91.40, 89.24, 19.87 ppm; MS (EI, 70 eV) m/z (%): 218 (M+, 100), 202
(92), 189 (9), 141 (12), 115 (15), 95 (9). (E)-1-(4-t-Butylphenyl)-4-phenylbut-
1-en-3-yne (3ad). Yellow solid, mp: 99–100 °C, IR (KBr): 2968, 1463, 1363, 955,
853, 813, 753, 688; 1H NMR (400 MHz, CDCl3) d 7.49–7.32 (m, 9H), 7.05 (d,
J = 16.0 Hz, 0.85H), 6.37 (d, J = 16.0 Hz, 0.85H), 1.34 (s, 9H); 13C NMR (100 MHz,
CDCl3)
128.25, 126.30, 123.21, 108.23, 91.95, 88.55, 29.71, 21.24 ppm; HRMS EI (m/z):
calcd for 17H14 218.1096; found, 218.1091. (E)-1-Phenyl-4-(2-
d 141.13, 138.02, 136.39, 132.10, 129.12, 128.74, 128.60, 128.59,
C
,
methylphenyl)-but-1-en-3-yne (3fa). Yellow oil; IR (KBr): 2923, 1486, 949,
751, 690; 1H NMR (400 MHz, CDCl3) d 7.47–7.27 (m, 6H), 7.23–7.12 (m, 3H),
7.03 (d, J = 16.4 Hz, 0.82H), 6.43 (d, J = 16.4 Hz, 0.82H), 2.49 (s, 3H); 13C NMR
(100 MHz, CDCl3) d 140.94, 140.12, 138.18, 136.44, 131.89, 129.49, 128.78,
128.60, 128.28, 126.33, 125.62, 123.19, 108.41, 92.82, 90.77, 20.79 ppm; HRMS
EI (m/z): calcd for
C17H14, 218.1096; found, 218.1091. (E)-1-Phenyl-4-(4-
bromophenyl)-but-1-en-3-yne (3ga). White solid, mp: 110–112 °C, IR (KBr):
2925, 1727, 1620, 1483, 1391, 1252, 1070, 824, 751, 690; 1H NMR (400 MHz,
CDCl3) d 7.48–7.44 (m, 4H), 7.35–7.28 (m, 5H), 7.05 (d, J = 16.4 Hz, 1H), 6.36 (d,
J = 16.0 Hz, 1H); 13C NMR (100 MHz, CDCl3) d 141.75, 136.19, 132.91, 131.63,
130.92, 128.78, 126.36, 122.40, 107.79, 90.61, 90.04, 65.64 ppm; HRMS EI (m/
CDCl3)
d 151.97, 141.18, 138.49, 133.64, 131.51, 131.46, 128.61, 128.42,
128.35, 128.11, 126.12, 125.72, 125.28, 123.55, 107.25, 106.46, 91.44, 89.19,
34.74, 31.25 ppm; HRMS EI (m/z): calcd for C20H20, 260.1565; found, 260.1561.
(E)-4-(4-Methoxyphenyl)-1-phenylbut-3-en-1-yne (3ae). Light yellow solid,
mp: 96–97 °C, IR (KBr): 2931, 1602, 1510, 1442, 1256, 1177, 957, 812, 754,
691; 1H NMR (400 MHz, CDCl3) d 7.51–7.46 (m, 2H), 7.39–7.32 (m, 5H), 7.01 (d,
J = 16.4 Hz, 0.92H), 6.93–6.87 (m, 2H), 6.25 (d, J = 16.0 Hz, 0.92H), 3.83 (s, 3H);
13C NMR (100 MHz, CDCl3) d 160.11, 140.89, 131.46, 129.22, 128.35, 128.02,
127.69, 123.62, 114.21, 105.70, 91.01, 89.28, 55.35 ppm; MS (EI, 70 eV) m/z (%):
234 (M+, 100), 201 (28), 191 (54), 165 (18), 94 (11). (E)-1-(4-fluorophenyl)-4-
phenyl-but-1-en-3-yne (3af). Light yellow solid, mp: 90–92 °C, IR (KBr): 2925,
1597, 1507, 1441, 1230, 956, 816, 756, 691; 1H NMR (400 MHz, CDCl3) d 7.49–
7.33 (m, 7H), 7.05 (d, J = 8.0 Hz, 2H), 7.01 (d, J = 16.0 Hz, 1H), 6.31 (d,
J = 16.0 Hz, 1H); 13C NMR (100 MHz, CDCl3) d 164.19, 161.72, 139.99, 132.61,
132.57, 131.54, 128.39, 128.27, 127.99, 127.91, 123.36, 115.91, 115.70, 107.93,
107.90, 91.76, 88.69 ppm; HRMS EI (m/z): calcd for C16H11F, 222.0845; found,
222.0841. (E)-1-(2,3,4,5,6-Pentafluorophenyl)-4-phenylbut-1-en-3-yne (3ag).
z): calcd for
C16H11Br, 282.0044; found, 282.0040. (E)-2,4-Dimethyl-8-
phenyloct-7-en-5-yn-4-ol (3ha). Yellow oil; IR (KBr): 3422, 2955, 2253,
2126, 1655, 1027, 824, 761; 1H NMR (400 MHz, DMSO) d 7.52 (d, J = 7.2 Hz,
2H), 7.39–7.27 (m, 3H), 6.89 (d, J = 16.4 Hz, 0.87H), 6.41 (d, J = 16.4 Hz, 0.87H),
5.24 (s, 0.9H), 1.99–1.87 (m, 1H), 1.57–1.41 (m, 5H), 0.99–0.94 (m, 6H); 13C
NMR (100 MHz, CDCl3) d 141.22, 136.21, 128.71, 128.60, 126.23, 107.74, 95.59,
82.73, 68.63, 51.95, 30.94, 25.23, 24.14 ppm; HRMS EI (m/z): calcd for C16H20O,
228.1514; found, 228.1519. (E)-1-Phenyl-dec-1-en-3-yne (3ia). Yellow oil; IR
(KBr): 2928, 2857, 1714, 1458, 952, 747, 694; 1H NMR (400 MHz, CDCl3) d
7.39–7.20 (m, 5H), 6.86 (d, J = 16.0 Hz, 1H), 6.15 (d, J = 16.4 Hz, 0.63H), 2.49–
2.17 (m, 2H), 1.60–1.25 (m, 8H), 0.92–0.84 (m, 3H); 13C NMR (100 MHz, CDCl3)
d 139.95, 136.62, 128.64, 128.19, 126.04, 108.93, 93.09, 79.72, 31.39, 29.71,
28.78, 22.57, 19.67, 14.07 ppm; HRMS EI (m/z): calcd for C16H20, 212.1565;
found, 212.1568.