4484 Organometallics, Vol. 29, No. 20, 2010
D’Amora et al.
1
(S)-(þ)-1-(2,20-Bipyridin-6-yl)ethanol 6. Saccharose (56 g) was
added to a stirred suspension of dry baker’s yeast (56 g) in
phosphate buffer (0.1 M, pH 7.4). The mixture was preincu-
bated for 30 min at 37 °C, and 6-acetyl-2,20-bipyridine (0.7 g,
3.6 mmol) was added at room temperature. The reaction was
monitored by HRGC, and after 2 days the broth was extracted
with ether. The organic phase was dried and evaporated to give a
residue, which was chromatographed on an SiO2 column
(petroleum ether/ethyl acetate as eluent), giving 75% yield at
93% conversion. ee = 99% (by HRCGC). [R]D þ21.7 (c 0.35,
CHCl3) [lit. [R]D þ26.0 (c 1.62, CHCl3)].33
1599, 1580 cm-1. H NMR (400 MHz, CDCl3): δ 4.14 (s, 3H,
CH3N), 4.76 (s, 2H, CH2OH), 4.82 (s, 1H, OH), 7.16 (d, 3J = 7.9
Hz, 1H, H3), 7.74 (t, J = 7.9 Hz, 1H, H4), 8.01 (d, J = 7.9 Hz,
0
1H, H5), 8.12 (s, 1H, H5 ). 13C NMR (100.1 MHz): δ 36.8 (q,
CH3N), 63.9 (t, CH2OH), 118.7 (d, C5), 119.6 (d, C3), 123.1 (d,
0
C5 ), 137.6 (d, C4), 148.1 (s), 148.9 (s), 158.7 (s). ESI-MS: 191.1
[Mþ], 214.1 [M þ Naþ]. Anal. Calcd for C9H10N4O: C, 56.83;
H, 5.30; N, 29.46. Found: C, 56.80; H, 5.28; N, 29.50.
2-(Methoxymethyl)-6-(1-methyl-1H-1,2,3-triazol-4-yl)pyridine
4. A solution of alcohol 12 (191 mg, 1 mmol) in 2.5 mL of dry THF
was dropwise added to suspension of NaH (44 mg, 60% in mineral
oil, 1.1 mmol) in dry THF, at 0 °C. After 30 min CH3I (142 mg, 62
μL, 1 mmol) was added at 0 °C from a septum, and the mixture was
allowed to reach rt, then quenched with aqueous saturated NH4Cl,
extracted with diethyl ether, and dried (Na2SO4). Evaporation of
the solvent left an oily residue, which was passed on a short SiO2
column (ethyl acetate), to give quantitatively compound 4 as a
(R)- and (S)-6-(1-Methoxyethyl)-2,20-bipyridine 1 were pre-
pared following the procedure described above; (R)-(þ)-(6-(1-
methoxyethyl)-2,20-bipyridine: ee > 99.9% (by HRCGC). [R]D
þ106.5 (c 0.6, CHCl3); (S)-(-)-(6-(1-methoxyethyl)-2,20-bipyr-
idine: ee = 99% (by HRCGC). [R]D -103.5 (c 0.4, CHCl3).
2-(Methoxymethyl)-6-(1H-1,2,3-triazol-1-yl)pyridine 4. (6-Bro-
mopyridin-2-yl)methanol 9. It was prepared in quantitative yield
by NaBH4 reduction of 6-bromo-2-pyridinecarboxaldehyde.36
Spectroscopical and analytical data were in accordance with the
literature.
white solid, mp 78-9 °C. IR (Nujol): 3147, 1604, 1578, 1116 cm-1
.
1H NMR (400 MHz, CDCl3): δ 3.42 (s, 3H, CH3O), 4.11 (s, 3H,
CH3N), 4.58 (s, 2H, CH2OMe), 7.32 (d, J = 7.7, 1H, H3), 7.72 (t,
0
J = 7.7, 1H, H4), 7.98 (d, J = 7.7, 1H, H5), 8.10 (s, 1H, H5 ). 13
C
(6-((Trimethylsilyl)ethynyl)pyridin-2-yl)methanol 10. It was
prepared following a literature method.37 Trimethylsilylacety-
lene (1.11 mL, 8.0 mmol) was added to a stirred solution of 9
(376 mg, 2.0 mmol), [Pd(PPh3)4] (48 mg, 0.08 mmol), and CuI
(11 mg, 0.08 mmol) in 8 mL of triethylamine. The mixture, from
which a white precipitate formed, was heated at 50 °C and then
cooled at room temperature. The conversion into the product
was complete in a few minutes (TLC with ethyl acetate, KMnO4
rev.) After addition of ether, the solution was washed with
aqueous NH4Cl (sat.), dried over Na2SO4, and evaporated to
give a crude product, which was used in the further step without
purification. For analytical purposes, a pure sample of 10 was
obtained by flash chromatography (eluent petroleum ether/
ethyl acetate, 3:2). 1H NMR (400 MHz, CDCl3): δ 0.36 (s, 9H,
Me3Si), 4.57 (s, 2H, CH2OH), 7.21 (d, 3J = 7.7 Hz, H5, 1H), 7.35
(d, 3J = 7.7 Hz, H3, 1H), 7.62 (t, 3J = 7.7 Hz, H4, 1H). 13C NMR
(100.1 MHz, CDCl3): δ -0.4 (q, SiMe3), 64.3 (t, CH2OH), 95.1
(s, acetylenic C2), 103.4 (s, acetylenic C1), 120.0 (d, C3 or C5),
126.0 (C5 or C3) 136.7 (d, C4), 141.8 (s, C6), 159.9 (s, C2). ESI-
MS: 206.1 [MHþ]. Anal. Calcd for C11H15NOSi: C, 64.34; H,
7.36; N, 6.82. Found: C, 64.35; H, 7.40; N, 6.85.
(6-Ethynylpyridin-2-yl)methanol 11. The crude 10 (410 mg, 2
mmol assuming a 100% yield in the previous step) was dissolved
in THF. Then Bu4N (1 M solution in THF, 3 mL, 3 mmol) was
added at room temperature. After 10 min stirring, ether was
added and the solution washed with water first, then with
saturated NH4Cl, and finally dried over Na2SO4 and evaporated
to give an oily residue, which was purified on column chromatog-
raphy (petroleum ether/ethyl acetate, 8:2): yield 78% after column
chromatography (eluent petroleum ether/ethyl acetate, 1:1); crys-
talline product, mp 108 °C. 1H NMR (400 MHz, CDCl3):δ3.15 (s,
1H, CCH), 3.90 (broad, OH), 4.73 (s, 2H, CH2OH), 7.29 (d, J =
7.9 Hz, 1H), 7.36 (d, J = 7.7 Hz, 1H), 7.64 (dd, J = 7.7 and 7.9 Hz,
1H). 13C NMR (100.1 MHz, CDCl3): δ 64.2 (t, CH2OH), 77.4 (d,
acetylenic C2), 82.4 (s, acetylenic C1), 120.4 (d, C3 or C5) 126.0 (d,
C5 or C3), 136.9 (d, C4), 141.0 (s, C6), 160.2 (s, C2). ESI-MS: 156.1
[M þ Naþ]. Anal. Calcd for C8H7NO: C, 72.16; H, 5.30; N, 10.52.
Found: C, 72.23; H, 5.31; N, 10.49.
NMR (100.1 MHz, CDCl3): δ 36.7 (q, CH3N), 58.7 (CH3O), 75.5
0
(t, CH2OMe), 118.7 (d, C5), 120.3 (d, C3), 123.1 (d, C5 ), 137.3 (d,
C4), 148.6 (s), 149.6 (s), 158.1 (s). ESI-MS 227.0 [M þ Naþ]. Anal.
Calcd for C10H12N4O: C, 58.81; H, 5.92; N, 27.43. Found: C,
58.78; H, 6.00; N, 27.50.
Oligomerization Reactions at Atmospheric CO Pressure. All
experiments were carried out in a three-necked, thermostated,
75 mL glass reactor equipped with a magnetic stirrer and
connected to a temperature controller. After establishment of
the reaction temperature (30 °C), the precatalyst, 1,4-benzoqui-
none, the vinyl arene, and TFE were placed inside. CO was
bubbled through the solution for 10 min; afterward a 4 L
balloon filled with CO was connected to the reactor. The system
was stirred at the same temperature for 24 h to give a yellow
solution. The reaction mixture was then poured into methanol
(100 mL) and stirred for 1 h at room temperature, and then the
solvent was evaporated to obtain a yellow-orange oil. The product
was dried under vacuum until constant weight was reached.
Oligo- and Polymerization Reactions at Higher CO Pressure.
€
A 10 mL Buchi Tinyclave glass reactor was used for these
reactions. The Tinyclave reactor was charged with 1,4-benzoqui-
none, the precatalyst, and TFE and was placed in an oil bath at
30 °C. Under a CO stream, the vinyl arene was added and the
reactor was pressurized at the operating CO pressure. The mixture
was stirred at the same temperature for 24 h. The reaction mixture
was poured into methanol, and the insoluble copolymer was
filtered off and dried under reduced pressure. The solution, con-
taining oligomers, was concentrated to obtain a yellow oil.
1H NMR (500 MHz, CDCl3, 298 K): CO/styrene: δ 8.21-7.10
(aromatic protons), 6.97 (m, Bl 1H, Ph-CHdCH-), 6.73 (pst, Al
1H, (Ph-CHdCH-), 6.41 (pst, Au 1H, (Ph-CHdCH-),
4.55-3.81 (broad, CO-CH(Ph)-), 4.03 (m, Al 1H, CH3-CH-
(Ph)-), 3.91 (m, Bl 1H, CH3-CH(Ph)-), 3.65 (m, Au 1H, CH3-
CH(Ph)-), 3.53-2.57 (broad, -(Ph)CH-CH2-CO-), 1.50 (d, Al
3H, -(Ph)CH-CH3), 1.48 (d, Au 3H, -(Ph)CH-CH3), 1.40 (d, Bl
3H, -(Ph)CH-CH3). 13C NMR (500 MHz, CDCl3, 298 K): δ
209.10-208.17 (broad, CO) 136.19 (Bl Ph-CHdCH-), 135.38 (Au
Ph-CHdCH-), 128.47 (Carom), 116.37 (Al Ph-CHdCH-),
53.28-52.02 (CO-CH(Ph)-), 53.23 (Bl CH3-CH(Ph)-), 52.42
(Al CH3-CH(Ph)-), 42.43 (Au CH3-CH(Ph)-), 44.26-42.32,
30.02, 29.47 (-(Ph)CH-CH2-CO-), 21.29 (Au -(Ph)CH-CH3),
17.63 (Al -(Ph)CH-CH3), 17.18 (Bl -(Ph)CH-CH3).
6-(1-Methyl-1H-1,2,3-triazol-4-yl)pyridin-2-yl)methanol 12.
Acetylene 11 (0.146 g, 1.1 mmol), CH3I (0.142 g, 1.0 mmol),
and sodium azide (0.071 g, 1.1 mmol) were suspended in a 1:1
mixture of water and tert-BuOH (1 mL each) in a 10 mL glass
vial equipped with a small magnetic stirring bar. CuI (0.1 g) was
added, and the mixture was irradiated under MW for 10 min at
100 °C, using an irradiation power of 100 W. A yellow pre-
cipitate was filtered off, and the solution concentrated to dry-
ness under vacuum, giving a residue from which compound 12
was obtained in a 74% yield after flash chromatography. White
solid, mp >200 °C. IR (Nujol): 3445 (broad), 3310 (sh), 3063,
Acknowledgment. Collaborative research was carried
out by S.G. and B.M. in the framework of the COST D40
project of EU. This work was supported by MIUR
(PRIN No. 2007HMTJWP_002), by Regione Friuli
Venezia Giulia. Engelhard Italia is gratefully acknowledged