H), 7.25 (dd, J = 1.0, 3.6 Hz, 1H, thiophene-H), 7.51 (d, J =
8.0 Hz, 1H, benzene-H).
3.6, 5.2 Hz, 1H, thiophene-H), 7.13 (dd, J = 1.2, 3.6 Hz, 1H,
thiophene-H), 7.17 (dd, J = 1.2, 5.2 Hz, 1H, thiophene-H),
7.34 (d, J = 8.8 Hz, 2H, benzene-H), 7.38 (d, J = 8.8 Hz, 2H,
benzene-H), 7.38-7.39 (m, 4H, benzene-H), 7.41-7.45 (m, 2H,
benzene-H), 7.71-7.74 (m, 4H, benzene-H); 13C NMR (101
MHz, CDCl3) ¤ 19.6, 26.6, 120.1, 122.1, 123.9, 127.0, 127.7,
127.97, 128.00, 130.1, 132.9, 135.6, 144.5, 155.4; EI-MS
(70 eV) m/z 414 (M+); Anal. Calcd For C26H26OSSi: C,
75.31%; H, 6.32%. Found: C, 75.24%; H, 6.33%.
Tributyl[5-(4-butylphenyl)-2-thienyl]stannane (3a): To a
stirred solution of compound 2a (476 mg, 2.20 mmol) in THF
(20 mL) was added n-butyllithium (BuLi) (0.90 mL of a 2.69 M
hexane solution, 2.4 mmol) at ¹78 °C. After stirring at ¹78 °C
for 1 h, tributylchlorostannane (Bu3SnCl) (0.72 mL, 2.6 mmol)
was added to the mixture. After the resulting mixture was
stirred for 3 h under ambient conditions, the solvent was evapo-
rated under reduced pressure. The residue was dissolved in
ethyl acetate and washed with water. The organic layer was
then dried over anhydrous magnesium sulfate and concentrat-
ed under reduced pressure to yield 1.52 g (quantitative) of the
crude compound 3a. The crude product was analyzed by
1H NMR and used directly in the next reaction without further
purification. Pale brown oil; 1H NMR (400 MHz, CDCl3) ¤
0.88-0.92 (m, 12H, CH3), 1.12 (t, J = 8.1 Hz, 6H, CH2), 1.29-
1.39 (m, 8H, CH2), 1.55-1.62 (m, 8H, CH2), 2.61 (t, J =
7.6 Hz, 2H, CH2), 7.12 (d, J = 3.2 Hz, 1H, thiophene-H), 7.17
(d, J = 8.4 Hz, 2H, benzene-H), 7.38 (d, J = 3.2 Hz, 1H,
thiophene-H), 7.53 (d, J = 8.4 Hz, 2H, benzene-H).
2-(4-Butoxyphenyl)thiophene (2b):
As described for
compound 2a, compound 2b was prepared from compound 1
(1.14 g, 7.00 mmol), 4-butoxyphenylboronic acid (1.49 g, 7.68
mmol), Cs2CO3 (4.56 g, 14.0 mmol), and Pd(PPh3)4 (401 mg,
0.347 mmol) in DMF (65 mL)/water (7 mL). Final purification
by column chromatography (silica gel, hexane:chloroform =
5:1) yielded 1.39 g (5.98 mmol, 85%) of compound 2b. The
product was fully characterized by 1H NMR and used in the next
reaction. Colorless crystals; 1H NMR (400 MHz, CDCl3) ¤ 0.98
(t, J = 7.1 Hz, 3H, CH3), 1.50 (sext, J = 7.1 Hz, 2H, CH2), 1.78
(quint, J = 7.1 Hz, 2H, CH2), 3.99 (t, J = 7.1 Hz, 2H, CH2),
6.90 (d, J = 8.8 Hz, 2H, benzene-H), 7.05 (dd, J = 3.6, 5.2 Hz,
1H, thiophene-H), 7.19 (dd, J = 1.2, 3.6 Hz, 1H, thiophene-H),
7.21 (dd, J = 1.2, 5.2 Hz, 1H, thiophene-H), 7.52 (d, J = 8.8
Hz, 2H, benzene-H).
2-[4-(N,N-Dibutylamino)phenyl]thiophene (2c):
As
described for compound 2a, compound 2c was prepared from
compound 1 (604 mg, 3.70 mmol), 2-(4-N,N-dibutylamino-
phen-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane (1.45 g, 4.38
mmol), Cs2CO3 (2.43 g, 7.46 mmol), and Pd(PPh3)4 (432 mg,
0.347 mmol) in DMF (40 mL)/water (4 mL). Final purification
by column chromatography (silica gel, hexane:triethylamine =
50:1) yielded 980 mg (3.41 mmol, 92%) of compound 2c. The
1
product was fully characterized by H NMR and used in the
1
next reaction. Yellow oil; H NMR (400 MHz, CDCl3) ¤ 0.96
(t, J = 7.6 Hz, 6H, CH3), 1.36 (sext, J = 7.6 Hz, 4H, CH2), 1.58
(quint, J = 7.6 Hz, 4H, CH2), 3.28 (t, J = 7.6 Hz, 4H, CH2),
6.63 (d, J = 8.9 Hz, 2H, benzene-H), 7.02 (dd, J = 3.8, 5.2 Hz,
2H, thiophene-H), 7.11 (dd, J = 1.2, 3.8 Hz, 1H, thiophene-H),
7.12 (dd, J = 1.2, 5.2 Hz, 1H, thiophene-H), 7.45 (d, J = 8.9
Hz, 2H, benzene-H).
Tributyl[5-(4-butoxyphenyl)-2-thienyl]stannane (3b): As
described for compound 3a, the crude compound 3b (yield:
1.52 g, quantitative) was prepared by the lithiation of com-
pound 2b (502 mg, 2.16 mmol) with BuLi (0.88 mL of a 2.69 M
hexane solution, 2.4 mmol), followed by stannylation with
Bu3SnCl (0.70 mL, 2.6 mmol). The crude product was analyzed
by 1H NMR and used directly in the next reaction without
2-(4-Hydroxyphenyl)thiophene (2d):
As described for
compound 2a, compound 2d was prepared from compound 1
(1.14 g, 6.99 mmol), 4-hydroxyphenylboronic acid (1.07 g, 7.76
mmol), Cs2CO3 (4.55 g, 14.0 mmol), and Pd(PPh3)4 (403 mg,
0.349 mmol) in DMF (40 mL)/water (4 mL). Final purification
by column chromatography (silica gel, hexane:ethyl acetate =
4:1) yielded 1.20 g (6.81 mmol, 97%) of compound 2d. The
1
further purification. Yellow oil; H NMR (400 MHz, CDCl3) ¤
0.90 (t, J = 8.0 Hz, 9H, CH3), 0.97 (t, J = 7.0 Hz, 2H, CH3),
1.11 (t, J = 8.0 Hz, 6H, CH2), 1.29-1.40 (m, 8H, CH2), 1.55-
1.64 (m, 8H, CH2), 3.96 (t, J = 7.0 Hz, 2H, CH2), 6.88 (d, J =
8.8 Hz, 2H, benzene-H), 7.10 (d, J = 3.3 Hz, 1H, thiophene-H),
7.31 (d, J = 3.3 Hz, 1H, thiophene-H), 7.53 (d, J = 8.8 Hz, 2H,
benzene-H).
1
product was fully characterized by H NMR and used in the
1
next reaction. Colorless crystals; H NMR (400 MHz, CDCl3)
¤ 4.93 (s, 1H, OH), 6.85 (d, J = 8.6 Hz, 2H, benzene-H),
7.05 (dd, J = 3.5, 5.0 Hz, 1H, thiophene-H), 7.19 (dd, J =
0.9, 3.5 Hz, 1H, thiophene-H), 7.21 (dd, J = 0.9, 5.0 Hz, 1H,
thiophene-H), 7.49 (d, 2H, J = 8.6 Hz, benzene-H).
Tributyl[5-(4-N, N-dibutylaminophenyl)-2-thienyl]-
stannane (3c): As described for compound 3a, the crude
compound 3c (yield: 1.46 g, quantitative) was prepared by the
lithiation of compound 2c (616 mg, 2.14 mmol) with BuLi
(0.91 mL of a 2.60 M hexane solution, 2.4 mmol), followed by
stannylation with Bu3SnCl (0.71 mL, 2.6 mmol). The crude
product was analyzed by 1H NMR and used directly in the next
2-(4-tert-Butyldiphenylsilanyloxyphenyl)thiophene (2e):
To a stirred solution of compound 2d (1.16 g, 6.58 mmol)
and imidazole (1.39 g, 20.4 mmol) in DMF (50 mL) was added
tert-butylchlorodiphenylsilane (1.92 mL, 7.49 mmol) at 0 °C.
After stirring for 18 h under ambient conditions, water was
added to the reaction mixture, and the resulting mixture extract-
ed with ethyl acetate. The organic layer was then dried over
anhydrous magnesium sulfate and the solvent was evaporated
under reduced pressure. The residue was purified by column
chromatography (silica gel, hexane:ethyl acetate = 4:1) to yield
2.60 g (6.27 mmol, 95%) of compound 2e. Colorless crystals;
1
reaction without further purification. Pale green oil; H NMR
(400 MHz, CDCl3) ¤ 0.90 (t, J = 8.0 Hz, 9H, CH3), 0.96 (t, J =
7.6 Hz, 6H, CH3), 1.10 (t, J = 8.0 Hz, 6H, CH2), 1.30-1.38 (m,
10H, CH2), 1.54-1.60 (m, 10H, CH2), 3.28 (t, J = 7.6 Hz, 4H,
CH2), 6.62 (d, J = 8.8 Hz, 2H, benzene-H), 7.08 (d, J = 3.2 Hz,
1H, thiophene-H), 7.24 (d, J = 3.2 Hz, 1H, thiophene-H), 7.46
(d, J = 8.8 Hz, 2H, benzene-H).
Tributyl[5-(4-tert-butyldiphenylsilanyloxyphenyl)-2-thie-
nyl]stannane (3e): As described for compound 3a, the crude
compound 3e (yield: 1.99 g, quantitative) was prepared by the
1
m.p. 89.3-89.5 °C; H NMR (400 MHz, CDCl3) ¤ 1.11 (s, 9H,
tBu), 6.76 (d, J = 8.8 Hz, 6H, benzene-H), 7.00 (dd, J =
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