Chemistry of bis(2-ethynyl-3-thienyl)arene and related systems, part 5: Preparation of an unsymmetrical 4,4′-bis(3-thienyl)biphenyl derivative containing a 2-[2-(diphenylphosphino)ethynyl]-3-thienyl moiety

Article abstract of DOI:10.1080/10426501003772037

An unsymmetrically substituted 4,4′-bis(3-thienyl)biphenyl derivative of 4-(2-ethynyl-3-thienyl)-4′-(3-thienyl)biphenyl type was prepared, utilizing 4-bromo-4′-(2-iodo-3-thienyl) biphenyl as synthetic intermediate. Reaction of 4-(2-ethynyl-3-thienyl)-4′-(3-thienyl) biphenyl with ethylmagnesium bromide followed by treatment with chlorodiphenylphosphine afforded 4-[2-(2-diphenylphosphinoethynyl)-3-thienyl]-4′-(3-thienyl) biphenyl. Copyright Taylor & Francis Group.

Full text of DOI:10.1080/10426501003772037

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Phosphorus, Sulfur, and Silicon and the
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Chemistry of Bis(2-ethynyl-3-
thienyl)arene and Related Systems, Part
5: Preparation of an Unsymmetrical
4,4’-Bis(3-thienyl)biphenyl
Derivative Containing a 2-[2-
(Diphenylphosphino)ethynyl]-3-thienyl
Moiety
Kozo Toyota a , Yasutomo Tsuji a & Noboru Morita a
a Department of Chemistry, Graduate School of Science , Tohoku
University , Sendai, Japan
Published online: 27 May 2010.
To cite this article: Kozo Toyota , Yasutomo Tsuji & Noboru Morita (2010) Chemistry of Bis(2-
ethynyl-3-thienyl)arene and Related Systems, Part 5: Preparation of an Unsymmetrical 4,4’-
Bis(3-thienyl)biphenyl Derivative Containing a 2-[2-(Diphenylphosphino)ethynyl]-3-thienyl
Moiety, Phosphorus, Sulfur, and Silicon and the Related Elements, 185:5-6, 983-991, DOI:
10.1080/10426501003772037
To link to this article: http://dx.doi.org/10.1080/10426501003772037
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Phosphorus, Sulfur, and Silicon, 185:983–991, 2010
Copyright ꢀC Taylor & Francis Group, LLC
ISSN: 1042-6507 print / 1563-5325 online
DOI: 10.1080/10426501003772037
CHEMISTRY OF BIS(2-ETHYNYL-3-THIENYL)ARENE AND
RELATED SYSTEMS, PART 5: PREPARATION OF AN
UNSYMMETRICAL 4,4’-BIS(3-THIENYL)BIPHENYL
DERIVATIVE CONTAINING A
2-[2-(DIPHENYLPHOSPHINO)ETHYNYL]-3-THIENYL
MOIETY
Kozo Toyota, Yasutomo Tsuji, and Noboru Morita
Department of Chemistry, Graduate School of Science, Tohoku University,
Sendai, Japan
An unsymmetrically substituted 4,4ꢀ-bis(3-thienyl)biphenyl derivative of 4-(2-ethynyl-3-
thienyl)-4ꢀ-(3-thienyl)biphenyl type was prepared, utilizing 4-bromo-4ꢀ-(2-iodo-3-thienyl)
biphenyl as synthetic intermediate. Reaction of 4-(2-ethynyl-3-thienyl)-4ꢀ-(3-thienyl)
biphenyl with ethylmagnesium bromide followed by treatment with chlorodiphenylphos-
phine afforded 4-[2-(2-diphenylphosphinoethynyl)-3-thienyl]-4ꢀ-(3-thienyl)biphenyl.
Keywords Artificial enzyme; artificial molecular architecture; heterocycles; oligoarene; phos-
phorus ligand
INTRODUCTION
Artificial enzymes1 as well as artificial molecular architecture2 are of current interest.
In the course of our continuing research on developing novel phosphorus ligands, such
as DPCBT3,4 and related polymers5 (Figure 1) as well as transition metal catalysts,6,7 we
designed 1,4-bis(2-ethynyl-3-thienyl)arene spacers [hereafter abbreviated as ETAr (Figure
1, n ≥ 2) or ETB (n = 1) spacers]. We have already prepared several compounds such
as 1a,b–3a,b containing the ETB or ETAr spacer8–11 (Figure 2). In addition, we recently
prepared the unsymmetrical ETB derivative 6 as well as monoethynyl compounds 4, 5,
and linked ETB compound 7.9,10 These compounds are promising building blocks for
the linked ETB system9 (Figure 1). For construction of more sophisticated systems such
as artificial enzymes, development of unsymmetrical 4,4ꢁ-bis(3-thienyl)biphenyl building
Received 20 November 2008; accepted 27 November 2008.
Dedicated to Professor Naomichi Furukawa on the occasion of his 70th birthday.
This work was supported in part by the Grants-in-Aid for Scientific Research (No. 20550030) from the
Ministry of Education, Culture, Sports, Science and Technology.
Address correspondence to Kozo Toyota, Department of Chemistry, Graduate School of Science, Tohoku
University, Aoba, Sendai 980-8578, Japan. E-mail: toyota@mail.tains.tohoku.ac.jp
983

984
K. TOYOTA ET AL.
Figure 1 Some spacers and systems containing thiophene.
blocks is desirable. We report in this article the preparation of unsymmetrical 4,4ꢁ-bis(3-
thienyl)biphenyl derivative 8 containing phosphorus ligand moiety, which may be regarded
as a part of a catalytic center of the ETB/ETAr-linked catalyst system.
RESULTS AND DISCUSSION
In our previously reported synthetic route to unsymmetrical 1,4-bis(2-ethynyl-3-
thienyl)benzene derivatives,10 1-bromo-4-(2-iodo-3-thienyl)benzene was used as a key
synthetic intermediate, because an ethynyl group can be introduced predominantly in the
2-position of the thiophene ring by the Sonogashira coupling reaction, and not in the ben-
zene ring or other positions, due to different reactivity of the iodo- and bromo-substituent.
Thus, in the present report, utilization of a similar intermediate, 4-bromo-4ꢁ-(2-iodo-3-
thienyl)biphenyl (11), was planned for the preparation of 8 (Scheme 1). 4-Bromo-4ꢁ-(3-
thienyl)biphenyl (10) was prepared from either 4,4ꢁ-dibromobiphenyl (Scheme 1, Route
A) or 1-iodo-4-(3-thienyl)benzene (9) (Route B). In the reaction of 4,4ꢁ-dibromobiphenyl
with 3-thiopheneboronic acid (Route A), compounds 10 and 4,4ꢁ-bis(3-thienyl)biphenyl
(14)9 as a byproduct were formed (Figure 3). Because both the desired product 10 and

UNSYMMETRICAL 4,4ꢀ-BIS(3-THIENYL)BIPHENYL DERIVATIVE
985
Figure 2 Structures of bisthienylarene derivatives.
the byproduct 14 were poorly soluble in common solvents, separation of 10 and 14 was
difficult, and the crude product 10 was used in the following reaction: Iodination of a
mixture of 10 and 14 with N-iodosuccinimide (NIS) afforded a mixture of 4-bromo-4ꢁ-
(2-iodo-3-thienyl)biphenyl (11) and 4,4ꢁ-bis(2-iodo-3-thienyl)biphenyl (15)9 in a 5:1 ratio.
Both products turned out to be soluble in hexane, and they were separated by column
chromatography to give pure 11 (46% yield based on 3-thiopheneboronic acid) and 15 (8%
yield based on 4,4ꢁ-dibromobiphenyl).
Figure 3 Structures of thienylbiphenyl derivatives.

986
K. TOYOTA ET AL.
Scheme 1
On the other hand, in Route B, a Suzuki–Miyaura coupling reaction of 1,4-
diiodobenzene with 3-thiopheneboronic acid at 75◦C for 1.5 h afforded 1-iodo-4-(3-
thienyl)benzene (9, 14% yield) and 1,4-bis(3-thienyl)benzene12 (ca. 40% yield), along
with a partial recovery of starting 1,4-diiodobenzene (44% recovery). This result indicates
that compound 9 is more reactive than 1,4-diiodobenzene.
Compound 9 was then converted to 10 by cross-coupling with 4-bromophenylboronic
acid. It should be noted that compound 10 was poorly soluble in hexane, while byproducts
of this reaction were easily soluble in hexane. Thus, we obtained 10 in 81% yield after
rinsing the crude product with hexane. Compound 10 was then reacted with NIS to give 11
in 74% yield. The total yield of 11 via Route B is 8% (based on 3-thiopheneboronic acid),
while via Route A the total yield is 36%. Consequently Route A is better than Route B.13
After we obtained 11 by both Routes A and B, conversion of 11 to a sub-
stituted 4,4ꢁ-bis(3-thienyl)biphenyl derivative was examined. A Sonogashira coupling

UNSYMMETRICAL 4,4ꢀ-BIS(3-THIENYL)BIPHENYL DERIVATIVE
987
of 11 with ethynyltrimethylsilane afforded 4-bromo-4ꢁ-[2-{2-(trimethylsilyl)ethynyl}-3-
thienyl]biphenyl (12) in 50% yield along with 4-[2-(trimethylsilyl)ethynyl]-4ꢁ-[2-{2-
(trimethylsilyl)ethynyl}-3-thienyl]biphenyl (16) in 23% yield. Compound 12 was then
subjected to Suzuki–Miyaura coupling reaction with 3-thiopheneboronic acid. Under reac-
tion conditions, coupling reaction and desilylation reaction took place and unsymmetrical
compound 13 was obtained in 53% yield. Compound 17 was also obtained as a byproduct
in 9% yield. Reaction of 13 with ethylmagnesium bromide followed by treatment with
chlorodiphenylphosphine afforded the desired phosphine ligand 8 in 43% yield. 31P NMR
chemical shift of 8 [δP (CDCl3) = –31.5] is close to that of the related species, Ph2PC≡CPh
[δP (CH2Cl2) = –33.6].14
It should be mentioned that we have already prepared unsymmetrical ETB derivative 6
by reaction of 1-bromo-4-[2-{2-(4-hexylphenyl)ethynyl}-3-thienyl]benzene with 2-[2-{2-
(4-butylphenyl)ethynyl}-5-methyl-3-thienyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane.10
Thus, preparation of unsymmetrical ETAr derivatives, containing two ethynyl groups,
seems to be easy using 12 and appropriate 2-(2-ethynyl-3-thienyl)-1,3,2-dioxaborolane
derivatives.
CONCLUSIONS
In summary, we have prepared unsymmetrical 4,4ꢁ-bis(3-thienyl)biphenyl derivatives,
utilizing 11 as a key intermediate. A fundamental synthetic technique for building blocks of
the linked ETAr system was developed, utilizing the chemistry of main group elements such
as phosphorus, sulfur, and silicon. This rather simple preparative method of unsymmetrical
ETAr-related species seems to help construction of sophisticated metal complex system
(such as metalloprotein mimetics or artificial enzymes), containing σ3λ3- as well as λ3σ2-
phosphorus atoms, the catalytic activities of which are of current interest.
EXPERIMENTAL
Melting points were measured on a Yanagimoto MP-J3 micro melting point apparatus
and are uncorrected. NMR spectra were recorded on a Bruker Avance-400 or AM-600, or
a JEOL JNM-GSX400 spectrometer. UV-vis spectra were measured on a Hitachi U-3210
spectrometer, while a Shimadzu FTIR-8100M spectrometer was used to obtain the IR
spectra. A Hitachi M-2500S spectrometer was used to obtain MS data. FT-ICR-MS spectra
were measured on a Bruker APEX III spectrometer.
1-Iodo-4-(3-thienyl)benzene (9)
A mixture of 1,4-diiodobenzene (3.13 g, 9.50 mmol), 3-thiopheneboronic acid (1.02 g,
7.94 mmol), tetrakis(triphenylphosphine)palladium (93.9 mg, 0.08 mmol), triphenylphos-
phine (319 mg, 1.22 mmol), K3PO4 (5.01 g, 23.59 mmol), 1,4-dioxane (40 mL), and water
(20 mL) was stirred at 75◦C for 1.5 h. After cooling to room temperature, insoluble mate-
rials (1.10 g) containing 1,4-bis(3-thienyl)benzene were removed by filtration. The filtrate
was worked up with chloroform (ca. 50 mL) and water (ca. 50 mL), and the organic phase
was dried over MgSO4. The solvent was removed under reduced pressure. The residue was
subjected to silica-gel column chromatography (eluent = hexane) to give 322 mg (1.13
mmol, 14% yield based on the thiopheneboronic acid) of 9 and 1.39 g (44% recovery) of
the starting 1,4-diiodobenzene.

988
K. TOYOTA ET AL.
1
Colorless powder, mp 150–152◦C; Rf = 0.38 (SiO2-hexane); H NMR (400 MHz,
CDCl3): δ = 7.32–7.35 (m, 3H, 4-thienyl, 3- and 5-phenyl), 7.39 (dd, J = 5.0, 2.9 Hz, 1H,
1
5-thienyl), 7.45 (dd, J = 2.9, 1.3 Hz, 1H, 2-thienyl), 7.72 (2H, 2- and 6-phenyl); 13C{ H}
NMR (100 MHz, CDCl3): δ = 92.3 (1-phenyl), 120.6 (2-thienyl), 125.9 (4-thienyl), 126.5
(5-thienyl), 128.1 (3- and 5-phenyl), 135.2 (4-phenyl), 137.8 (2- and 6-phenyl), 141.1 (3-
thienyl); IR (KBr): ν = 1902, 1524, 1482, 1416, 1401, 1358, 1341, 1300, 1267, 1252, 1202,
1117, 1090, 1063, 1001, 893, 864, 828, 777, 704, 691, 629, 502 cm−1; EI-MS (70 eV) m/z
(rel. intensity): 286 (M+; 100), 159 (M+–I; 8). Found: m/z 285.9311. Calcd for C10H7IS:
M, 285.9313. Found: C, 41.54; H, 2.62%. Calcd for C10H7IS: C, 41.98; H, 2.47%.
4-Bromo-4ꢀ-(3-thienyl)biphenyl (10)
Route A. A mixture of 4,4ꢁ-dibromobiphenyl (4.71 g, 15.1 mmol), 3-
thiopheneboronic acid (2.00 g, 15.7 mmol), tetrakis(triphenylphosphine)palladium
(135 mg, 0.117 mmol), triphenylphosphine (657 mg, 2.50 mmol), K3PO4 (16.1 g, 75.6
mmol), 1,4-dioxane (70 mL), and water (30 mL) was heated at 90◦C for 5 h. After cooling
to room temperature, the insoluble product was separated by filtration, and the solid was
rinsed with hexane, collected by filtration, and dried to give 4.33 g of crude 10, containing
4,4ꢁ-bis(3-thienyl)biphenyl (14) as a byproduct. This product was used in the following
reaction in Route A without further purification.
Route B. A mixture of 9 (236 mg, 0.825 mmol), 4-bromophenylboronic acid (169
mg, 0.843 mmol), tetrakis(triphenylphosphine)palladium (14.4 mg, 0.012 mmol), K2CO3
(538 g, 2.53 mmol), 1,4-dioxane (40 mL), and water (20 mL) was heated at room tempera-
ture for 4.5 h and then at 75◦C for 15 h. After cooling to room temperature, chloroform (ca.
50 mL) and water (ca. 50 mL) were added to the reaction mixture, the organic phase was
separated and dried over MgSO4. The solvent was removed under reduced pressure. The
residue was rinsed with hexane and the resulting insoluble solid was collected by filtration.
The solid was then washed with a small amount of chloroform and dried to give 210 mg
(0.666 mmol, 81% yield) of 10.
10: Colorless powder, mp 253–257◦C; Rf = 0.18 (SiO2-hexane); 1H NMR (400 MHz,
CDCl3) δ = 7.40–7.44 (2H, m, 4- and 5-thienyl), 7.48–7.51 (3H, m, 2-thienyl and phenyl),
7.57 (2H, AAꢁBBꢁ, phenyl), 7.59 (2H, AAꢁBBꢁ, phenyl), and 7.68 (2H, AAꢁBBꢁ, phenyl);
IR (KBr) 1534, 1480, 1422, 1389, 1310, 1200, 1123, 1103, 1075, 1011, 1001, 968, 893,
864, 853, 820, 781, 733, 685, 671, 633, 552, 513, and 430 cm−1; EI-MS (70 eV) m/z (rel
intensity) 316 (M++2; 100), 314 (M+; 99), and 234 (M+–Br–1; 12). Found: m/z 313.9761.
Calcd for C16H11BrS: M, 313.9765. Found: C, 60.96; H, 3.52%. Calcd for C16H11BrS: C,
60.24; H, 3.74%. The 13C NMR spectrum was not measured due to the low solubility.
4-Bromo-4ꢀ-(2-iodo-3-thienyl)biphenyl (11)
Route A. Crude 4-bromo-4ꢁ-(3-thienyl)biphenyl 10 was prepared as described
above and used in the following reaction. A mixture of crude 10 (2.07 g, ca. 6.7 mmol),
N-iodosuccinimide (NIS, 1.42 g, 6.30 mmol), 2,2ꢁ-azobis(2-methylpropionitrile) (AIBN,
101 mg, 0.615 mmol), and acetic acid (40 mL) in chloroform (60 mL) was stirred at 50◦C
for 3 h. Chloroform (ca. 60 mL) and water (ca. 80 mL) were added to the reaction mixture
at room temperature, and the organic phase was treated with saturated aqueous NaHCO3
and then saturated aqueous Na2S2O3 solution. The organic phase was washed with brine,

UNSYMMETRICAL 4,4ꢀ-BIS(3-THIENYL)BIPHENYL DERIVATIVE
989
dried over MgSO4, and the solvent was removed under reduced pressure. The residue was
treated with a silica-gel column chromatography (hexane:CHCl3 9:1) to give 1.52 g of
11 (3.44 mmol, ca. 52% yield from crude 10; 46% theoretical yield based on the starting
3-thiopheneboronic acid) and 298 mg of 4,4ꢁ-bis(2-iodo-3-thienyl)biphenyl (15) (0.523
mmol, 8% theoretical yield based on the starting 4,4ꢁ-dibromobiphenyl).
Route B. A mixture of pure 10 (210 mg, 0.666 mmol), NIS (153 mg, 0.681 mmol),
AIBN (19 mg, 0.12 mmol), and acetic acid (15 mL) in chloroform (20 mL) was stirred at
50◦C for 3 h. Chloroform (ca. 20 mL) and water (ca. 30 mL) were added to the reaction
mixture at room temperature, and the organic phase was treated with saturated aqueous
NaHCO3 and then saturated aqueous Na2S2O3 solution. The organic phase was washed
with brine, dried over MgSO4, and the solvent was removed under reduced pressure. The
residue was treated with a silica-gel column chromatography (CCl4) to give 218 mg of 11
(0.493 mmol, 74% yield).
11: Colorless powder, mp 131–133◦C; Rf = 0.25 (SiO2-hexane); 1H NMR (400 MHz,
CDCl3) δ = 7.00 (1H, d, J = 5.5 Hz, 4-thienyl), 7.50–7.57 (3H, m, 5-thienyl and phenyl),
1
and 7.58–7.64 (6H, m, phenyl); 13C{ H} NMR (100 MHz, CDCl3) δ = 73.1 (2-thienyl),
121.7 (4-phenyl), 126.7 (phenyl), 128.6 (phenyl), 128.9 (4-thienyl), 129.2 (phenyl), 131.3
(5-thienyl), 131.9 (phenyl), 135.8 (4ꢁ-phenyl), 139.1 (phenyl), 139.4 (phenyl), and 146.0
(3-thienyl); IR (KBr) 1607, 1588, 1534, 1482, 1387, 1347, 1308, 1244, 1130, 1076, 1001,
963, 872, 851, 814, 752, 743, 712, 677, 650, 629, 619, 558, 502, and 477 cm−1; EI-MS (70
eV) m/z (rel intensity) 442 (M++2; 100), 440 (M+; 97), and 234 (M+–I–Br; 26). Found:
m/z 439.8731. Calcd for C16H10BrIS: M, 439.8731. Found: C, 43.23; H, 2.56%. Calcd for
C16H10BrIS: C, 43.56; H, 2.28%.
4-Bromo-4ꢀ-[2-{2-(trimethylsilyl)ethynyl}-3-thienyl]biphenyl (12)
A mixture of 11 (503 g, 1.141 mmol), ethynyltrimethylsilane (240 µL, 1.70 mmol),
dichlorobis(triphenylphosphine)palladium(II) (111 mg, 0.159 mmol), copper(I) iodide (23
mg, 0.12 mmol), and diisopropylamine (20 mL) in THF (30 mL) was stirred at 50◦C for
24 h. After cooling to room temperature, chloroform (ca. 100 mL) and water (ca. 100 mL)
were added to the reaction mixture. The organic phase was dried over MgSO4. The solvent
was removed under reduced pressure, and the residue was treated with a silica-gel column
chromatography (hexane:chloroform = 9:1) to give 233 mg (0.567 mmol, 50% yield) of
12 and 112 mg (0.261 mmol, 23% yield based on 11) of 16.
1
12: Colorless solid, mp 134–136◦C; Rf = 0.53 (SiO2-CCl4); H NMR (400 MHz,
CDCl3) δ = 0.26 (9H, s, SiMe3), 7.23 (1H, d, J = 5.2 Hz, 4-thienyl), 7.27 (1H, d, J =
5.2 Hz, 5-thienyl), 7.50 (2H, d, J = 8.6 Hz, 2- and 6-phenyl), 7.57–7.61 (2H+2H, m,
1
phenyl), and 7.91 (2H, d, J = 8.4 Hz, phenyl); 13C{ H} NMR (100 MHz, CDCl3) δ = –0.3
(SiMe3), 98.1 (C≡C), 101.8 (C≡C), 118.1 (2-thienyl), 121.6 (4-phenyl), 126.5 (4-thienyl),
126.7 (phenyl), 127.5 (5-thienyl), 128.3 (phenyl), 128.5 (phenyl), 131.8 (phenyl), 134.4
(4ꢁ-phenyl), 139.0 (phenyl), 139.5 (phenyl), and 144.5 (3-thienyl); IR (KBr) 2145 (C≡C),
1609, 1532, 1482, 1389, 1248, 1181, 1096, 1075, 1011, 1001, 880, 814, 764, 747, 723, 706,
675, 656, 646, 558, 492, and 432 cm−1; EI-MS (70 eV) m/z (rel intensity) 412 (M++2;
100), 410 (M+; 91), 397 (M+–Me+2; 50), 395 (M+–Me; 47), and 301 (M+–Br–2Me; 34).
Found: m/z 410.0156. Calcd for C21H19BrSSi: M, 410.0160. Found: C, 60.27; H, 4.62%.
Calcd for C21H19BrSSi·(H2O)1/2: C, 59.99; H, 4.79%.
1
16: Colorless solid, mp 152–155◦C; Rf = 0.46 (SiO2-CCl4); H NMR (400 MHz,
CDCl3) δ = 0.26 (9H, s, SiMe3), 0.27 (9H, s, SiMe3), 7.23 (1H, d, J = 5.3 Hz, 4-thienyl),

990
K. TOYOTA ET AL.
7.27 (1H, d, J = 5.3 Hz, 5-thienyl), 7.55 (2H, AAꢁBBꢁ, phenyl), 7.59 (2H, AAꢁBBꢁ,
1
phenyl), 7.63 (2H, AAꢁBBꢁ, phenyl), and 7.91 (2H, AAꢁBBꢁ, phenyl); 13C{ H} NMR
(100 MHz, CDCl3) δ = –0.3 (SiMe3), –0.1 (SiMe3), 94.9 (C≡C), 98.2 (C≡C), 101.8
(C≡C), 104.9 (C≡C), 118.0 (2-thienyl), 122.0 (4-phenyl), 126.5 (4-thienyl), 126.6 (phenyl),
126.8 (phenyl), 127.5 (5-thienyl), 128.2 (phenyl), 132.4 (phenyl), 134.4 (4ꢁ-phenyl), 139.3
(phenyl), 140.5 (phenyl), and 144.5 (3-thienyl); IR (KBr) 2157 (C≡C), 2143 (C≡C), 1491,
1250, 1094, 1003, 865, 840, 824, 758, and 725 cm−1; EI-MS (70 eV) m/z (rel intensity)
428 (M+; 100), 413 (M+–Me; 41), and 73 (Me3Si+; 6). FT-ICR-MS Found: m/z 451.1342.
Calcd for C26H28NaSSi2: M++Na, 451.1342.
4-(2-Ethynyl-3-thienyl)-4ꢀ-(3-thienyl)biphenyl (13)
A mixture of 12 (312 mg, 0.757 mmol), 3-thiopheneboronic acid (119 mg, 0.926
mmol), tetrakis(triphenylphosphine)palladium (14 mg, 0.012 mmol), triphenylphosphine
(33 mg, 0.13 mmol), K3PO4 (863 mg, 4.06 mmol), 1,4-dioxane (80 mL), and water (20 mL)
was heated at 80◦C for 12 h. After cooling to room temperature, chloroform (ca. 100 mL)
and water (ca. 100 mL) were added to the reaction mixture. The organic phase was washed
with brine and dried over MgSO4. The solvent was removed under reduced pressure, and
the residue was treated with a silica-gel column chromatography (CCl4) to give 138 mg
(0.40 mmol, 53% yield) of 13 and 24 mg (0.070 mmol, 9% yield) of 17.
1
13: Pale yellow solid, mp 223–226◦C (decomp); Rf = 0.39 (SiO2-CCl4); H NMR
(400 MHz, CDCl3) δ = 3.47 (1H, s, C≡CH), 7.23 (1H, d, J = 5.3 Hz, 4-thienyl), 7.31
(1H, d, J = 5.3 Hz, 5-thienyl), 7.42 (1H, dd, J = 5.1 Hz and 2.9 Hz, 5ꢁ-thienyl), 7.45 (1H,
dd, J = 5.1 Hz and 1.4 Hz, 4ꢁ-thienyl), 7.51 (1H, dd, J = 2.9 Hz and 1.4 Hz, 2ꢁ-thienyl),
7.69–7.71 (6H, m, phenyl), and 7.87 (2H, AAꢁBBꢁ, phenyl); IR (KBr) 3287, 3100, 2095
(C≡C), 1528, 1491, 1431, 1418, 1401, 1202, 1088, 1001, 878, 864, 830, 781, 749, 727, 706,
671, 656, 631, 592, and 502 cm−1; EI-MS (70 eV) m/z (rel intensity) 342 (M+; 100). Found:
m/z 342.0533. Calcd for C22H14S2: M, 342.0537. 13C NMR spectrum was not measured
because of the poor solubility.
1
17: Pale yellow solid, mp 124–126◦C (decomp); Rf = 0.52 (SiO2-CCl4); H NMR
(600 MHz, CDCl3) δ = 3.46 (1H, s, C≡CH), 7.20 (1H, d, J = 5.3 Hz, 4-thienyl), 7.29
(1H, d, J = 5.3 Hz, 5-thienyl), 7.49 (2H, AAꢁBBꢁ, phenyl), 7.57 (2H, AAꢁBBꢁ, phenyl),
1
7.61 (2H, AAꢁBBꢁ, phenyl), and 7.84 (2H, AAꢁBBꢁ, phenyl); 13C{ H} NMR (150 MHz,
CDCl3) δ = 77.3 (C≡C), 83.7 (C≡C), 117.0 (2-thienyl), 121.7 (4-phenyl), 126.9 (thienyl),
127.0 (phenyl), 127.8 (thienyl), 128.4 (phenyl), 128.6 (phenyl), 131.9 (phenyl), 134.4 (ipso-
phenyl), 139.2 (ipso-phenyl), 139.5 (ipso-phenyl), and 145.2 (3-thienyl); IR (KBr) 3287,
3104, 2095 (C≡C), 1586, 1480, 1428, 1389, 1125, 1078, 1011, 1001, 878, 855, 816, 781,
747, 725, 671, 656, 598, and 494 cm−1; EI-MS (70 eV) m/z (rel intensity) 340 (M++2;
100), 338 (M+; 98), and 258 (M+–Br–1; 54). Found: m/z 337.9760. Calcd for C18H11BrS2:
M, 337.9765.
4-[2-(2-Diphenylphosphinoethynyl)-3-thienyl]-4ꢀ-(3-thienyl)biphenyl (8)
To a solution of 13 (105 mg, 0.307 mmol,) in THF (20 mL), 0.32 mmol of ethyl-
magnesium bromide (1.0 mol/L solution in THF) was added, and the resulting mixture
was stirred at 0◦C for 30 min. Chlorodiphenylphosphine (0.06 mL, 0.32 mmol) was added
to the mixture at 0◦C, and the reaction mixture was stirred at room temperature for 1 h.

UNSYMMETRICAL 4,4ꢀ-BIS(3-THIENYL)BIPHENYL DERIVATIVE
991
Chloroform (ca. 50 mL) and water (ca. 50 mL) were added to the reaction mixture. The or-
ganic phase was separated and dried over MgSO4. The solvent was removed under reduced
pressure, and the residue was treated with an alumina column chromatography (CHCl3) to
give 84 mg (0.14 mmol, 43% yield) of 8.
8: Pale yellow solid, mp 181–183◦C; Rf = 0.57 (Al2O3-CCl4); 1H NMR (600 MHz,
CD2Cl2) δ = 7.21 (1H, d, J = 4.9 Hz, 4-thienyl), 7.25–7.28 (6H, m, phenyl), 7.31 (1H,
d, J = 4.9 Hz, 5-thienyl), 7.36 (1H, dd, J = 4.7 Hz and 2.9 Hz, 5ꢁ-thienyl), 7.40 (1H,
dd, J = 4.7 Hz and 1.5 Hz, 4ꢁ-thienyl), 7.48 (1H, dd, J = 2.9 Hz and 1.5 Hz, 2ꢁ-thienyl),
7.52–7.56 (4H, m, phenyl), 7.55 (2H, AAꢁBBꢁ, 2- and 6-biphenyl), 7.60 (2H, AAꢁBBꢁ,
2ꢁ- and 6ꢁ-biphenyl), 7.64 (2H, AAꢁBBꢁ, 3ꢁ- and 5ꢁ-biphenyl), and 7.78 (2H, AAꢁBBꢁ, 3-
1
and 5-biphenyl); 13C{ H} NMR (150 MHz, CD2Cl2) δ = 91.8 (d, JPC = 10.0 Hz, C≡C),
100.2 (C≡C), 116.7 (2-thienyl), 119.6 (2ꢁ-thienyl), 125.4 (4ꢁ-thienyl), 125.7 (5ꢁ-thienyl),
126.0 (2-,6- or 3ꢁ-,5ꢁ-biphenyl), 126.1 (2-,6- or 3ꢁ-,5ꢁ-biphenyl), 126.5 (2ꢁ- and 6ꢁ-biphenyl),
3
127.0 (5-thienyl), 127.1 (4-thienyl), 127.7 (3- and 5-biphenyl), 127.9 (d, JPC = 7.2 Hz,
2
m-phenyl), 128.4 (p-phenyl), 131.9 (d, JPC = 20.0 Hz, o-phenyl), 133.3 (4-biphenyl),
134.2 (4ꢁ-biphenyl), 135.1 (d, 1JPC = 7.2 Hz, ipso-phenyl), 138.3 (1ꢁ-biphenyl), 139.1 (1-
1
biphenyl), 140.9 (3ꢁ-thienyl), and 144.8 (3-thienyl); 31P{ H} NMR (162 MHz, CDCl3) δ =
−31.5; UV (CH2Cl2) 296 nm (log ε 4.54); IR (KBr) 2963, 2137 (C≡C), 1526, 1491, 1478,
1433, 1418, 1368, 1262, 1202, 1094, 1026, 1003, 876, 866, 828, 783, 749, 695, 633, 540,
513, and 451 cm−1. FT-ICR-MS Found: m/z 549.0873. Calcd for C34H23NaPS2: M+Na+,
549.0876.
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