Palladium-catalyzed reactions of aryl iodides with trimethylsilylacetylenes and disubstituted alkynes: The synthesis of diarylacetylenes and triarylethylenes

Article abstract of DOI:10.1016/S0040-4020(01)00758-X

Treatment of 2.5 equiv. of aryl iodide with trimethylsilylacetylene in the presence of 3 equiv. of sodium methoxide and 5 mol% of Pd(PPh₃)₄ under refluxing methanol for 6 h gave diarylacetylene in good chemical yields. When the catalyst was replaced by Pd(dba)₂ and 5 equiv. of aryl iodide were added under the same reaction conditions, triarylethylenes were obtained in 70-85% yields. Only the sterically hindered o-methoxyiodobenzene and 2-iodothiophene gave the diarylacetylene, but also in good chemical yield. Reaction of aryl iodides with disubstituted alkynes in the presence of Pd(OAc)₂ and sodium methoxide in methanol produced trisubstituted ethylenes in modest to good yields. The hydrogenolysis of the organopalladium is proposed through β-hydride elimination of the palladium methanolate intermediates.

Full text of DOI:10.1016/S0040-4020(01)00758-X

TETRAHEDRON
Pergamon
Tetrahedron 57 /2001) 7839±7844
Palladium-catalyzed reactions of aryl iodides with
trimethylsilylacetylenes and disubstituted alkynes: the synthesis of
diarylacetylenes and triarylethylenes
Ming-Jung Wu,a,p Li-Mei Wei,a,b Chi-Fong Lin,a Shiow-Piaw Leoua and Li-Lan Weia,b
aSchool of Chemistry, Kaohsiung Medical University, Kaohsiung, Taiwan, ROC
bFooyin Institute of Technology, Kaohsiung County, Taiwan, ROC
Received 27 March 2001; revised 25June 2001; accepted 19 July 2001
AbstractÐTreatment of 2.5equiv. of aryl iodide with trimethylsilylacetylene in the presence of 3 equiv. of sodium methoxide and 5mol%
of Pd/PPh3)4 under re¯uxing methanol for 6 h gave diarylacetylene in good chemical yields. When the catalyst was replaced by Pd/dba)2 and
5equiv. of aryl iodide were added under the same reaction conditions, triarylethylenes were obtained in 70±85% yields. Only the sterically
hindered o-methoxyiodobenzene and 2-iodothiophene gave the diarylacetylene, but also in good chemical yield. Reaction of aryl iodides
with disubstituted alkynes in the presence of Pd/OAc)2 and sodium methoxide in methanol produced trisubstituted ethylenes in modest to
good yields. The hydrogenolysis of the organopalladium is proposed through b-hydride elimination of the palladium methanolate
intermediates. q 2001 Elsevier Science Ltd. All rights reserved.
In recent years, diarylacetylenes have received a great deal
of attention due to their spectroscopic and electronic
properties.1,2 Triarylethylenes are also of interest because
of their spectroscopic and electronic properties3 as well as
their biological activities.4 Although numerous synthetic
routes to these compounds have been reported,5 most of
the reported methods were carried out in stepwise pro-
cedure. For instance, the palladium-catalyzed coupling of
aryl halides with mono-substituted acetylenes to give the
disubstituted compounds and the palladium-catalyzed
reaction of aryl iodides or tri¯ates with disubstituted
acetylenes to give trisubstituted alkenes.6 Only two methods
described the one-step synthesis of diarylacetylenes from
acetylene gas7 or trimethylsilylacetylene.8 No report has
described a one-step reaction to the synthesis of triaryl-
ethylene from trimethylsilylacetylene or acetylene gas.
We describe herein an ef®cient method for the synthesis
of symmetrical diarylacetylenes and triarylethylenes from
aryl iodides and trimethylsilylacetylene under palladium
catalysis in methanol and in the presence of sodium
methoxide, as well as the unsymmetrical triarylethylenes
from aryl iodides with diarylacetylenes under the same
reaction conditions.
Various of aryl iodides 1a±e reacted with trimethylsilyl-
acetylene in the presence of 3 equiv. of sodium methoxide
in methanol using Pd/PPh3)4 as a catalyst gave the diaryl-
acetylenes in 63±91% yields. The results are summarized in
Scheme 1. The reaction of o-methoxyphenyl iodide
produced the diarylacetylene in 84% yield which indicated
that steric hinderance has little effect on this coupling
reaction. However, when bromobenzene was used in this
reaction, only biphenyl was obtained in 20% yield, and no
coupling adduct was formed. /Eq. /1)) 2-iodothiophene gave
Scheme 1.
Keywords: palladium and compounds; hydrogenolysis; b-hydride elimination; diarylacetylenes; triarylethylenes.
Corresponding author. Tel.: 1886-7-3121101, ext. 2220; fax: 1886-7-3125339; e-mail: mijuwu@cc.kmu.edu.tw
p
0040±4020/01/$ - see front matter q 2001 Elsevier Science Ltd. All rights reserved.
PII: S0040-4020/01)00758-X

7840
M.-J. Wu et al. / Tetrahedron 57 &2001) 7839±7844
Scheme 2.
no product at all, after stirring the reaction mixture under
re¯ux overnight.
Pd/OAc)2, 5mol% of PPh 3 and 5atom equiv. of sodium in
CH3OH. Stirring this reaction mixture at room temperature
for 24 h gave, after chromatography, triphenylethylene /3a)
in 51% yield. When Pd/dba)2 was used as the catalyst with-
out triphenylphosphine ligand, the reaction gave the same
product in 49% yield. Using Pd/PPh3)4 as the catalyst
provided no addition adduct and most of the starting
materials were recovered. The optimal conditions were
found with 2 equiv. of iodobenzene and Pd/OAc)2 as the
catalyst in this case, the reaction produced triphenylethylene
in 64% yield. Other aryl iodides were also employed with
the optimal conditions and the results are summarized in
Table 1. When p-tri¯uoromethyliodobenzene was employed
in this reaction, the reaction took place much slower and
required re¯uxing to obtain the addition adduct.
ꢀ1†
When 5equiv. of iodobenzene was used under the same
reaction conditions except for 24 h reaction times, diphenyl-
acetylene was obtained in 32% yield and triphenylethylene
was produced in 49% yield. When the catalyst was replaced
by Pd/dba)2, reaction of 5equiv. of iodobenzene with
1 equiv. of trimethylsilylacetylene under the same reaction
conditions for 6 h, gave triphenylethylene in 85% yield.
/Scheme 2) Under the same reaction conditions, p-methoxy-
iodobenzene and p-iodotoluene gave the corresponding
triarylethylene in 71 and 79% yields, respectively.
o-Methoxyiodobenzene and 2-iodothiophene gave only
diarylacetylenes 2b and 2e in 76 and 80%, respectively.
This is probably due to the steric hinderance of o-methoxy-
iodobenzene and the poor reactivity of 2-iodothiophene,
thus preventing the addition reaction of aryl iodides with
diarylacetylenes.
Several unsymmetrical disubstituted alkynes have also been
examined in the palladium-catalyzed hydroarylation with
aryl iodides. The results are summaried in Table 2. We
®rst tested /p-methoxyphenyl)-phenylacetylene /2f) with
p-iodotoluene under the optimal conditions. This reaction
produced 4f and 5f in 42 and 18% yields, respectively.
When /o-methoxyphenyl)phenylacetylene /2g) was
employed in this reaction, compounds 4g and 5g were
obtained in 24 and 37% yields, respectively. These results
indicate that the steric effects or the methoxyl coordination
to palladium probably overcome the electronic effects in
directing the addition reactions. In the cases of compound
2h and 2i, the reactions favor the addition of the aryl group
to the less sterically hindered site to give 4h and 4i as the
major products, respectively. Reaction of 2j with iodo-
benzene gave 5j in 40% yield along with 10% of dimer.
This result indicates that both electronic and steric effects
strongly in¯uence the regioselectivity of this addition
reaction. Bromobenzene has also been employed in this
reaction, but with diphenylacetylene under the optimal
Although the palladium-catalyzed addition of aryl or vinyl
halides or tri¯ates to internal alkynes has been reported,6 all
of these methods used formic acid or its salts. The use of
palladium catalyst in methanol with sodium methoxide
represents an alternative route to trisubstituted alkenes.
This ®nding encouraged us to investigate this hydroaryl-
ation of aryl halides with internal alkynes. We ®rst
examined the hydroarylation of 1,2-diphenylacetylene /2a)
with iodobenzene /1.2 equiv.) in the presence of 5mol% of
Table 1. Palladium-catalyzed addition of aryl iodides with 1,2-diphenylacetylene
Aryl iodides
Reaction time /h)
Temperature /8C)
Productsa /yield, %)
2a ArˆC6H5
24
24
24
24
48
25
25
25
25
3a /64%)
3h /69%)
3g /69%)
3f /72%)
3i /52%)b
2b Arˆo-CH3OC6H4
2c Arˆp-CH3OC6H4
2d Arˆp-CH3C6H4
2k Arˆp-CF3C6H4
re¯ux
a
1
Yields refer to isolated yields. All of the compounds gave satisfactory H 13C NMR and mass spectral data.
Based on recovered starting material.
b

M.-J. Wu et al. / Tetrahedron 57 &2001) 7839±7844
7841
Table 2. Palladium-catalyzed addition of aryl iodides with unsymmetrical disubstituted alkynes
Alkynes
Ar
Temp /8C)/Time /h)
Products /yields, %)a,b
2f, Rˆp-CH3OC6H4
2g, Rˆo-CH3OC6H4
2h, RˆCH2OH
p-CH3C6H4
p-CH3C6H4
p-CH3C6H4
p-CH3C6H4
C6H5
25/24
25/48
re¯ux/24
re¯ux/24
re¯ux/24
4f /42%)
4g /24%)
4h /37%)
4i /37%)
5f /18%)
5g /37%)c
2i, RˆCH2CH2CH3
5i /12%)
5j /40%)d
2j, Rˆo-NCC6H4
Yields refer to isolated yields. All of the compounds gave satisfactory 1H 13C NMR and mass spectral data.
Regioisomeric ratios were calculated by GC and NMR.
The structure of 5g was unambiguously determined by X-ray crystallography.
10% yield of dimer was also obtained.
a
b
c
d
Scheme 3.
reaction conditions, only the reduction adduct, stilbene, was
obtained in 38% yield. /Eq. /2))
hydroarylation reaction as shown in Scheme 3. This
mechanism involves the addition of arylpalladium
complex to the alkyne to give the vinylpalladium adduct
6. Replacement of iodide with methoxide gives 7,9
followed by b-hydride elimination10 to give the hydrid-
palladium 8. Reductive elimination of 8 affords the
product 3. The isotope study supported the proposed
mechanism which demonstrated that the hydrogen
source for hydrogenolysis was the a-hydrogen of
methanol.
ꢀ2†
To investigate the mechanism of this addition reaction, two
reactions were carried out. Treatment of p-iodotoluene with
diphenylacetylene under the optimal conditions using
CH3OD as the solvent gave the product 3f in 48% yield.
No deuterium incorporation was found in this product.
However, when CD3OD was used as the solvent, the deutero
adduct 3f0 was obtained in 50% yield.
In conclusion, we have developed ef®cient synthetic
methods for the synthesis of diarylacetylenes and tri-
arylethylenes, and good chemical yields were obtained in
most cases. For the directed synthesis of triarylethylenes
from trimethylsilylacetylene, Pd/dba)2 is found to be a
more ef®cient catalyst than Pd/PPh3)4. We have also
demonstrated that reaction of aryl iodides with disubsti-
tuted alkynes in the presence of Pd/OAc)2 and sodium
methoxide in methanol gave trisubstituted ethylenes
in reasonable yields. A mechanism of the hydroaryl-
ation reaction is proposed through a b-hydride elimi-
nation of palladium methanolate which provides an
alternative route for hydrogenolysis of organo-
palladiums.
According to the results, we proposed a mechanism for this

7842
M.-J. Wu et al. / Tetrahedron 57 &2001) 7839±7844
1. Experimental
1H NMR /CDCl3, 400 MHz) d 7.01±7.35/m, 15H), 6.97 /s,
1H); MS/EI) m/z 256 /M1, 95%).
Method A. To a stirred solution of trimethylsilylacetylene
/1 mmol) in dry methanol /7 mL) was added sequentially
the aryl iodide /2.5mmol), Pd/PPh 3)4 /0.05mmol) and
sodium metal /3 mmol). The resulting solution was heated
under re¯ux and stirred at this temperature for 6 h. After
cooling to room temperature, the solvent was removed in
vacuo. The residue was diluted with saturated aqueous NaCl
solution and extracted with EtOAc /3£10 mL). The extracts
were dried over anhydrous MgSO4. After removal of
solvent, the residue was puri®ed by ¯ash column chromato-
graphy to give the products.
1.1.7. 1,1,2-Tris*4-methoxyphenyl)ethylene *3c). Obtained
by method B in 71% yield as a white solid. mp 71±728C
1
/lit.,16 69±708C). H NMR /CDCl3, 400 MHz) d 7.24 /d,
2H, Jˆ8.4 Hz), 7.12 /d, 2H, Jˆ8.4 Hz), 6.96 /d, 2H,
Jˆ8.4 Hz), 6.87 /d, 2H, Jˆ8.4 Hz), 6.83 /d, 2H,
Jˆ8.4 Hz), 6.78 /s, 1H), 6.67 /d, 2H, Jˆ8.4 Hz), 3.84 /s,
3H), 3.81 /s, 3H), 3.75/s, 3H); MS/EI) m/z 346 /M1, 92%).
1.1.8. 1,1,2-Tris*4-methylphenyl)ethylene *3d). Obtained
by method B in 79% yield as a white solid. mp 84±858C
/lit.,17 82±848C). 1H NMR /CDCl3, 400 MHz) d 7.09±7.26
/m, 8H), 6.95/s, 4H), 6.89 /s, 1H), 2.39 /s, 3H), 2.36 /s, 3H),
2.28 /s, 3H); MS/EI) m/z 298 /M1, 98%).
Method B. Same as method A except 5equiv. of aryl iodide
was used.
1.1.9. *E)-1-*4-Methylphenyl)-1,2-diphenylethylene *3f).
Obtained by the reaction of p-methyliodobenzene with
diphenylacetylene /method C) in 72% yield as a white
1.1. General procedure for hydroarylation of disubsti-
tuted acetylenes *Method C)
1
solid. mp 74±758C. H NMR /CDCl3, 400 MHz) d 7.12±
To a stirred solution of diarylacetylene /1 mmol) and aryl
iodide /1.2 mmol) in methanol /5mL) in the presence of
Pd/OAc)2 /5mol%) and PPh 3 /5mol%) was added a freshly
cut sodium /5atom equiv.). The reaction mixture was stir-
red at room temperature for 24 h. Solvent was then removed
in vacuo. The residue was treated with saturated aqueous
ammonium chloride solution /10 mL) and extracted with
EtOAc /3£10 mL). The combined organic extracts were
washed with brine and dried over anhydrous MgSO4.
After removal of solvent, the residue was puri®ed by
column chromatography /silica gel) to give the products.
7.34 /m, 12H), 7.03 /d, 2H, Jˆ7.7 Hz), 6.95/s, 1H), 2.37 /s,
3H). 13C NMR /CDCl3, 100 MHz) d 142.5, 140.6, 140.5,
137.5, 137.4, 130.4, 129.5, 128.9, 128.6, 127.9, 127.5,
127.3, 126.6, 112.3, 21.1. Anal. Calcd for C21H18: C,
93.28; H, 6.72. Found: C, 93.23; H, 6.77.
1.1.10. *E)-1-*4-Methoxyphenyl)-1,2-diphenylethylene
*3g). Obtained by the reaction of p-methoxyiodobenzene
with diphenylacetylene /method C) in 69% yield as an oil.
1H NMR /CDCl3, 200 MHz) d 7.23±7.36 /m, 7H), 7.04±
7.15/m, 5H), 6.92 /s, 1H), 6.87 /d, 2H, Jˆ8.9 Hz), 3.83 /s,
3H). 13C NMR /CDCl3, 5 0 MHz)d 159.2, 142.1, 140.5,
137.6, 136.0, 130.4, 129.4, 128.7, 128.6, 127.9, 127.3,
126.5, 126.4, 113.6, 55.3; EI/MS) m/z /rel. intensity) 286
/M1, 100); HRMS /EI) calcd for C21H18O 286.1358, found
286.1359.
1.1.1. Diphenylacetylene *2a). Obtained by method A in
91% yield as a white solid. mp 60±618C /lit.,11 59±618C).
1H NMR /CDCl3, 400 MHz) d 7.57±7.62 /m, 4H), 7.31±
7.42 /m, 6H); MS/EI) m/z 178 /M1, 92%).
1.1.2. 1,2-Bis*2-methoxyphenyl)acetylene *2b). Obtained
by method A in 84% yield as a white solid. mp 124±1258C
/lit.,12 127±1288C). 1H NMR /CDCl3, 400 MHz) d 7.52 /dd,
2H, Jˆ7.6, 1.6 Hz), 7.26±7.31 /m, 2H), 6.88±6.95/m, 4H),
3.92 /s, 6H); MS/EI) m/z 238 /M1, 94%).
1.1.11. *E)-1-*2-Methoxyphenyl)-1,2-diphenylethylene
*3h). Obtained by the reaction of o-methoxyiodobenzene
with diphenylacetylene /method C) in 69% yield as a
1
white solid. mp 71±728C. H NMR /CDCl3, 200 MHz) d
7.27±7.32 /m, 7H), 7.10±7.23 /m, 5H), 7.00 /d, 1H,
Jˆ6.2 Hz), 6.90 /d, 1H, Jˆ8.5Hz), 6.82 /s, 1H), 3.62 /s,
3H). 13C NMR /CDCl3, 100 MHz) d 157.3, 141.1, 140.4,
137.5, 133.7, 131.0, 130.2, 129.6, 129.5, 128.7, 127.9,
127.8, 126.7, 126.5, 120.5, 111.9, 55.6; Anal. Calcd for
C21H18O: C, 88.07; H, 6.34. Found: C, 88.12; H, 6.41.
1.1.3. 1,2-Bis*4-methoxyphenyl)acetylene *2c). Obtained
by method A in 76% yield as a white solid. mp 146±
1
1478C /lit.,13 1428C). H NMR /CDCl3, 400 MHz) d 7.44
/d, 4H, Jˆ8.4 Hz), 6.86 /d, 4H, Jˆ8.4 Hz), 3.82 /s, 6H);
MS/EI) m/z 238 /M1, 100%).
1.1.12. *E)-1-*4-Tri¯uoromethylphenyl)-1,2-diphenyl-
ethylene *3i). Obtained by the reaction of p-tri¯uoromethyl-
iodobenzene with diphenylacetylene /method C) in 52%
1.1.4. 1,2-Bis*4-methylphenyl)acetylene *2d). Obtained by
method A in 63% yield as a white solid. mp 138±1398C
/lit.,14 134±1358C). 1H NMR /CDCl3, 400 MHz) d 7.41 /d,
4H, Jˆ8.4 Hz), 7.14 /d, 4H, Jˆ8.4 Hz), 2.36 /s, 6H);
MS/EI) m/z 206 /M1, 100%).
1
yield as an oil. H NMR /CDCl3, 200 MHz) d 7.56 /d,
2H, Jˆ8.1 Hz), 7.42 /d, 2H, Jˆ8.1 Hz), 7.05±7.38 /m,
10H), 7.02 /s, 1H). 13C NMR /CDCl3, 5 0 MHz)d 146.9,
141.3, 139.6, 136.8, 131.6, 130.9, 130.3, 130.0, 129.6,
128.7, 128.1, 127.8, 127.3, 125.2, 125.1; EI/MS) m/z /rel.
intensity) 324 /M1, 100); HRMS /EI) calcd for C21H15F3
324.1126, found 324.1126.
1.1.5. 1,2-Bis*2-thienyl)acetylene *2e). Obtained by
method B in 63% yield as a white solid. mp 101±1028C
1
/lit.,8 93±958C). H NMR /CDCl3, 400 MHz) d 7.26±7.32
/m, 4H), 7.01 /dd, 2H, Jˆ5.2, 3.0 Hz); MS/EI) m/z 190 /M1,
100%).
1.1.13. 1-*4-Methylphenyl)-1-*4-methoxyphenyl)-2-phenyl-
ethylene *4f) and 1-*4-methylphenyl)-1-phenyl-2-*4-meth-
oxyphenyl)ethylene *5f). Obtained by the reaction of
1.1.6. 1,1,2-Trisphenylethylene *3a). Obtained by method
B in 85% yield as a white solid. mp 73±748C /lit.,15 738C).

M.-J. Wu et al. / Tetrahedron 57 &2001) 7839±7844
7843
p-methyliodobenzene with phenyl/4-methoxyphenyl)-
1.1.17.
2-*2,2-Diphenylethenyl)benzonitrile
*5j).
acetylene /method C) in 60% yield as a 7:3 ratio as an oil.
1H NMR /CDCl3, 200 MHz) d 7.46±7.51 /m, 0.9H), 7.07±
7.36 /m, 8.1H), 6.66±6.98 /m, 5H), 3.84 /s, 2.1H), 3.75 /s,
0.9H), 2.40 /s, 0.9H), 2.37 /s, 2.1H); EI/MS) m/z /rel. inten-
sity) 300 /M1, 100); HRMS /EI) calcd for C22H20O
300.1514, found 300.1520.
Obtained by the reaction of iodobenzene with 2-/2-phenyl-
ethynyl)benzonitrile /method C) in 40% yield as a white
solid. mp 124±1258C. 1H NMR /CDCl3, 200 MHz) d
7.60±7.64 /m, 1H), 7.30±7.64 /m, 7H), 7.15±7.28 /m,
6H), 6.90±6.95/m, 1H). 13C NMR /CDCl3, 5 0 MHz)d
147.3, 142.2, 141.3, 139.3, 132.7, 131.7, 130.4, 129.8,
129.2, 128.6, 128.4, 128.3, 128.2, 128.1, 126.8, 123.5,
118.2; Anal. Calcd for C21H15N: C, 89.64; H, 5.38; N,
4.98. Found: C, 89.66; H, 5.38; N, 5.03.
1.1.14. 1-*4-Methylphenyl)-1-*2-methoxyphenyl)-2-phenyl-
ethylene *4g) and 1-*4-methylphenyl)-1-phenyl-2-*2-meth-
oxyphenyl)ethylene *5g). Reaction of p-methyliodobenzene
with phenyl/2-methoxyphenyl)acetylene /method C) gave 4g
in 24% yield as an oil and 5g in 37% yield as a white solid.-
Chromatography solvent system uses ethyl acetate±hexane:
Acknowledgements
1
1:400. Spectra data for 4g: H NMR /CDCl3, 400 MHz) d
We would like to thank the National Science Council of the
Republic of China for ®nancial support.
7.34 /td, 1H, Jˆ7.6, 1.0 Hz), 7.25/dd, 2H, Jˆ8.0, 1.0 Hz),
7.08±7.14 /m, 6H), 7.05/s, 1H), 6.93±7.05/m, 4H), 3.59 /s,
3H), 2.34 /s, 3H). 13C NMR /CDCl3, 5 0 MHz)d 157.5,
139.9, 138.8, 137.7, 137.0, 131.6, 129.4, 129.1,
128.9,128.9, 127.9, 127.8, 126.5, 126.4, 121.1, 111.6, 55.6,
21.1; HRMS /EI) calcd for C22H20O 300.1514, found
300.1517. Spectra data for 5g: mp 75 ±786C. 1H NMR
/CDCl3, 400 MHz) d 7.11±7.29 /m, 10H), 7.08 /s, 1H),
6.84 /d, 1H, Jˆ8.0 Hz), 6.77 /dd, 1H, Jˆ7.2, 1.2 Hz), 6.60
/td, 1H, Jˆ8.0, 0.8 Hz), 3.83 /s, 3H), 2.36 /s, 3H). 13C NMR
/CDCl3, 100 MHz) d 157.9, 142.4, 141.0, 140.8, 137.1,
130.6, 130.4, 130.2, 128.8, 128.2, 128.0, 127.8, 127.0,
122.5, 119.8, 110.3, 55.4, 21.1; EI/MS) m/z /rel. intensity)
300 /M1, 100); HRMS /EI) calcd for C22H20O 300.1514,
found 300.1515.
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1.1.15. 2-*4-Methylphenyl)-3-phenyl-2-propen-1-ol *4h).
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1
white solid. mp 78±798C. H NMR /CDCl3, 200 MHz) d
7.50 /d, 2H, Jˆ7.8 Hz), 7.34±7.43 /m, 5H), 7.24 /d, 2H,
Jˆ7.8 Hz), 6.97 /s, 1H), 4.71 /s, 2H), 2.40 /s, 3H), 1.70 /s,
1H). 13C NMR /CDCl3, 50 MHz) d 140.0, 137.5, 137.0,
130.4, 130.4, 129.4, 128.9, 128.3, 127.2, 126.4, 60.3, 21.1;
Anal. Calcd for C16H16O: C, 85.67; H, 7.19. Found: C,
85.02; H, 7.11.
1.1.16. 1-Phenyl-2-*4-methylphenyl)-1-pentene *4i) and
1-phenyl-1-*4-methylphenyl)-1-pentene *5i). Reaction of
p-methyliodobenzene with 1-phenyl-1-pentyne /method C)
gave 4i in 37% yield as a white solid and 5i in 12% yield as
an oil. Chromatography solvent system uses hexane. Spectra
6. Cacchi, S.; Felici, M.; Pietroni, B. Tetrahedron Lett. 1984, 25,
3137.
7. Kundu, N. G.; Pal, M. J. Chem. Soc., Perkin Trans. 1 1996,
449.
8. D'Auria, M. Synth. Commun. 1992, 22, 2393.
9. Pd/II) alcoholates are the key intermediates in palladium-
catalyzed arylation of alcohol with aryl halides. /a) Mann,
G.; Incarvito, C.; Rheingold, A. L.; Hartwig, J. F. J. Am.
Chem. Soc. 1999, 121, 3224. /b) Aranyos, A.; Old, D. W.;
Kiyomori, A.; Wolfe, J. P.; Sadighi, J. P.; Buchwald, S. L.
J. Am. Chem. Soc. 1999, 121, 4369. /c) Kim, T. J.; Osakada,
K.; Takenaka, A.; Yamamoto, A. J. Am. Chem. Soc. 1990,
112, 1096.
1
data for 4i: mp 39±408C. H NMR /CDCl3, 200 MHz) d
7.32±7.41 /m, 7H), 7.20 /d, 2H, Jˆ8.2 Hz), 6.71 /s, 1H),
2.68 /t, 2H, Jˆ7.7 Hz), 2.40 /s, 3H), 1.43±1.56 /m, 2H),
0.92 /t, 3H, Jˆ7.4 Hz). 13C NMR /CDCl3, 5 0 MHz)d
143.1, 140.2, 138.5, 136.8, 129.0, 128.8, 128.2, 127.6,
126.5, 126.4, 32.1, 22.0, 21.1, 14.1; Anal. Calcd for
C18H20: C, 91.46; H, 8.54. Found: C, 91.41; H, 8.58. Spectra
1
data for 5i: H NMR /CDCl3, 200 MHz) d 7.35/dd, 2H,
Jˆ7.8, 1.8 Hz), 7.17 /dd, 2H, Jˆ7.8, 1.8 Hz), 7.04±7.12 /m,
5H), 6.05 /t, 1H, Jˆ7.5Hz), 2.32 /s, 3H), 2.08 /q, 2H,
Jˆ7.6 Hz), 1.40±1.55 /m, 2H), 0.90 /t, 3H, Jˆ7.3 Hz).
13C NMR /CDCl3, 5 0 MHz)d 141.4, 140.5, 140.1, 136.4,
129.9, 129.2, 128.7, 128.0, 127.1, 126.7, 31.8, 23.2, 21.0,
13.8; EI/MS) m/z /rel. intensity) 236 /M1, 68), 207
/100); HRMS /EI) calcd for C18H20 236.1565, found
236.1567.
10. /a) Halpern, J.; Goldman, A. S. J. Am. Chem. Soc. 109, 109,
7537. /b) Bryndza, H. E.; Calabrese, J. C.; Marsi, M.; Roe,
D. C.; Tam, W.; Bercaw, J. E. J. Am. Chem. Soc. 1986, 108,
4805. /c) Zask, A.; Helquist, P. J. Org. Chem. 1978, 43, 1619.
11. Catalog Handbook of Fine Chemicals, Aldrich Chemical Co.,
Milwaukee, 1998±1999, p 689.
12. Suzuki, T.; Kitamura, T.; Sonada, T.; Kobayashi, S.;
Taniguchi, H. J. Org. Chem. 1981, 46, 5324.

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13. Karmarkar, P. G.; Thakar, A. A.; Wadia, M. S. Tetrahedron
Lett. 1981, 22, 2301.
16. Kamata, M.; Murayama, K.; Miyashi, T. Tetrahedron Lett.
1989, 30, 4129.
17. Lee, C. C.; Paine, A. J.; Ko, E. C. F. Can. J. Chem. 1977, 55,
2310.
14. Colvin, E. W.; Hamill, B. D. J. Chem. Soc., Perkin Trans 1
1977, 869.
15. Fox, M. A. J. Am. Chem. Soc. 1979, 101, 5339.