Self-Assembly of 3-[4′-(Diethylboryl)phenyl]pyridine
J . Org. Chem., Vol. 64, No. 19, 1999 7007
temperature)/1 Torr (lit.12 bp 140-142 °C/2 Torr). The 1H NMR
[t, J ) 7.6 Hz, -B(CH2CH3)2], 1.00-1.15 [m, -B(CH2CH3)2],
6.50 (dd, J ) 5.8, 8.0 Hz, H-5 of pyridyl), 6.98 (d, J ) 7.7 Hz,
H-4′ of phenylene), 7.21 (H-5′ of phenylene), 7.23 (d, J ) 7.5
Hz, H-2′ of phenylene), 7.32 (dt, J ) 1.6, 8.0 Hz, H-4 of pyridyl),
7.67 (d, J ) 7.4 Hz, H-6′ of phenylene), 8.07 (d, J ) 5.5 Hz,
H-6 of pyridyl), 8.57 (s, H-2 of pyridyl); another component
0.83 [t, J ) 7.6 Hz, -B(CH2CH3)2], 1.00-1.15 [m, -B(CH2-
CH3)2], 6.53 (dd, J ) 5.8, 8.0 Hz, H-5 of pyridyl), 7.07 (d, J )
7.5 Hz, H-4′ of phenylene), 7.23 (d, J ) 7.5 Hz, H-5′ of
phenylene), 7.28 (s, H-2′ of phenylene), 7.44 (dd, J ) 1.5, 8.0
Hz, H-4 of pyridyl), 7.50 (d, J ) 7.3 Hz, H-6′ of phenylene),
7.98 (d, J ) 5.5 Hz, H-6 of pyridyl), 8.57 (s, H-2 of pyridyl);
13C NMR (126 MHz, acetone-d6) 10.0, 15.2, 15.7, 124.0, 124.2,
126.2, 126.3, 126.4, 128.67, 128.75, 129.1, 131.3, 131.8, 134.2,
134.3, 134.5, 134.6, 138.8, 140.6, 144.4, 144.6, 145.0, 145.1,
145.3; 11B NMR (128 MHz, CDCl3,) 2.09 (s), 32.35 (m), 33.31
(m), 55.21 (w); 11B NMR (128 MHz, THF-d8) 2.27 (s), 19.84
and MS spectra are consistent with previously reported data:
12
IR (neat) 1593, 1576, 1559, 1468, 1190 cm-1 13C NMR (100
;
MHz, CDCl3) 122.9, 123.4, 125.5, 129.9, 130.3, 130.8, 134.0,
134.9, 139.6, 147.9, 148.8. Anal. Calcd for C11H8NBr: C, 56.44;
H, 3.44; N, 5.98. Found: C, 56.49; H, 3.40; N, 6.13.
3-[4′-(Dieth ylbor yl)p h en yl]p yr id in e (3). To an ethereal
solution (10 mL) of 6 (630 mg, 2.692 mmol) and TMEDA (410
µL, 2.70 mmol) was added dropwise a hexane solution of
n-butyllithium (1.55 M, 1.91 mL, 2.961 mmol) at -78 °C over
2 min, and the whole was stirred for 1 h. To this was added a
THF solution of diethylmethoxyborane (1.0 M, 8.1 mL, 8.1
mmol) at -78 °C, and the mixture was stirred for 1 h. After
being warmed to 0 °C, the mixture was stirred for additional
0.5 h, diluted with ethyl acetate (100 mL), washed with water
(30 mL) and brine (10 mL × 2), and dried over MgSO4. After
removal of the solvent, the residue was chromatographed on
deactivated (5% H2O) silica gel (10 g) with a mixture of benzene
and hexane (1:1) as an eluent to give 3 (368 mg, 61.3%): faint
yellow solid; mp 125-141 °C; IR (KBr) 2864, 1582, 1478, 1429,
1387, 1259 cm-1; EI-MS (20 eV) 446 (0.2, 2M+), 418 (1.9, 2M+
- Et + 1), 223 (36, M+), 194 (100, M+ - Et); ES-MS (LiCl in
THF, negative mode) 481.0 (7, [2M + Cl]-), 257.9 (100, [M +
Cl]-); 1H NMR (500 MHz, acetone-d6) 0.61 [t, 6 H, J ) 7.6 Hz,
-B(CH2CH3)2], 0.82-0.94 [m, 4 H, -B(CH2CH3)2], 7.25 (d, 2
H, J ) 8.6 Hz, H-2′, -6′ of phenylene), 7.28 (d, 2 H, J ) 8.6 Hz,
H-3′, -5′ of phenylene), 7.90 (dd, 1 H, J ) 5.8, 7.9 Hz, H-5 of
pyridyl), 8.17 (s, 1 H, H-2 of pyridyl), 8.39 (dd, 1 H, J ) 1.2,
7.9 Hz, H-4 of pyridyl), 8.73 (d, 1 H, J ) 5.8 Hz, H-6 of pyridyl);
1H NMR (600 MHz, toluene-d8) major component 0.99 [t, J )
7.6 Hz, -B(CH2CH3)2], 1.03-1.18 [m, -B(CH2CH3)2], 6.63 (dd,
J ) 5.8, 7.7 Hz, H-5 of pyridyl), 6.96 (d, J ) 8.2 Hz, H-2′, -6′
of phenylene), 7.27 (H-4 of pyridyl), 7.35 (d, J ) 8.2 Hz, H-3′,
-5′ of phenylene), 8.22 (d, J ) 5.5 Hz, H-6 of pyridyl), 8.30 (d,
J ) 1.9 Hz, H-2 of pyridyl); minor component 0.94 [t, J ) 7.7
Hz, -B(CH2CH3)2], 1.03-1.18 [m, -B(CH2CH3)2], 6.51 (dd, J
) 5.6, 8.1 Hz, H-5 of pyridyl), 7.20 (d, J ) 8.2 Hz, H-2′, -6′ of
phenylene), 7.27 (d, J ) 8.2 Hz, H-3′, -5′ of phenylene), 7.35
(H-4 of pyridyl), 8.02 (d, J ) 5.5 Hz, H-6 of pyridyl), 8.71 (d, J
) 1.8 Hz, H-2 of pyridyl); 13C NMR (100 MHz, acetone-d6) 10.1,
15.9, 125.9, 126.2, 126.4, 126.5, 129.1, 132.4, 134.2, 134.4,
138.8, 140.3, 144.1, 144.5, 145.9; 11B NMR (128 MHz, CDCl3)
2.50 (strong), 31.41 (weak), 32.36 (w); 11B NMR (160 MHz,
acetone-d6) 3.18 (s), 33.48 (w); 11B NMR (160 MHz, toluene-
d8) -4.56 (s), 2.22 (s), 31.83 (medium), 32.64 (m); 11B NMR
(128 MHz, THF-d8) 2.81 (s), 20.39 (w), 29.25 (w), 32.66 (m).
Anal. Calcd for C15H18NB: C, 80.75; H, 8.13; N, 6.28. Found:
C, 80.94; H, 8.24; N, 5.61.
(w), 29.11 (w), 31.99 (m), 32.54 (m); Anal. Calcd for C15H18
-
NB: C, 80.75; H, 8.13; N, 6.28. Found: C, 80.93; H, 8.32; N,
5.40.
1-P h en yl-4-(3′-p yr id yl)ben zen e (8). A mixture of 3 (96
mg, 0.430 mmol), bromobenzene (70 µL, 0.665 mmol), pow-
dered KOH (73 mg, 1.301 mmol), Bu4NBr (70 mg, 0.217 mmol),
and Pd(Ph3P)4 (25 mg, 0.022 mmol) in THF (5 mL) was stirred
at 80 °C for 1.5 h. The mixture was diluted with AcOEt (40
mL), washed with brine (10 mL × 2), and dried over MgSO4.
After removal of the solvent, the residue was purified by
column chromatography (SiO2, 4 g) with a mixture of benzene
and ether (4:1 v/v) to afford 8 (80 mg, 80.5%): faint yellow
crystals; mp 147.0-148.5 °C (lit.13 mp: 152-153 °C); IR (KBr)
1582, 1474, 1397 cm-1; EI-MS (70 eV) 231 (M+, 100), 202 (12),
1
152 (6); H NMR (500 MHz, CDCl3) 7.36-7.39 (m, 2 H, H-5′
of pyridyl and H-4′′ of phenyl), 7.47 (t, 1 H, J ) 7.6 Hz, H-3′′,
-5′′ of phenyl), 7.64 (d, 2 H, J ) 7.0 Hz, H-2′′, -6′′ of phenyl),
7.66 (dt, 2 H, J ) 2.1, 8.5 Hz, H-3, -5 of phenylene or H-2, -6
of phenylene), 7.71 (dt, 2 H, J ) 2.1, 8.5 Hz, H-2, -6 of
phenylene or H-3, -5 of phenylene), 7.91 (dt, 1 H, J ) 2.0, 7.9
Hz, H-4′ of pyridyl), 8.60 (d, 1 H, J ) 3.4 Hz, H-6′ of pyridyl),
8.90 (d, 1 H, J ) 2.1 Hz, H-2′ of pyridyl); 13C NMR (126 MHz,
CDCl3) 123.5, 127.0, 127.4, 127.5, 127.7, 128.3, 128.8, 134.1,
136.1, 136.6, 140.3, 140.9, 148.2, 148.5. Anal. Calcd for
C
17H13N: C, 88.28; H, 5.67; N, 6.06. Found: C, 87.48; H, 5.58;
N, 5.93.
1-P h en yl-3-(3′-p yr id yl)ben zen e (9). A mixture of 4 (94
mg, 0.420 mmol), bromobenzene (70 µL, 0.665 mmol), pow-
dered KOH (76 mg, 1.360 mmol), Bu4NBr (73 mg, 0.226 mmol),
and Pd(Ph3P)4 (26 mg, 0.023 mmol) in THF (5 mL) was stirred
at 80 °C for 2.5 h. The mixture was diluted with AcOEt (50
mL), washed with brine (10 mL × 2), and dried over MgSO4.
After removal of the solvent, the residue was purified by
column chromatography (SiO2, 3.5 g) with a mixture of benzene
and ether (4:1 v/v) to afford 9 (77 mg, 79.7%) as a yellow oil,
bp 130-140 °C (bath temperature)/1 Torr (lit.14 mp 151-152
°C). We could not induce crystallization in 9 even by cooling
in the freezer: IR (neat) 3032, 1599, 1586, 1574, 1474, 1422,
1393 cm-1; EI-MS (70 eV) 231 (M+, 100), 202 (12), 152 (6); 1H
NMR (400 MHz, CDCl3) 7.37-7.41 (m, 2 H, H-5′ of pyridyl
and H-4′′ of phenyl), 7.45-7.50 (m, 2 H, H-3′′, -5′′ of phenyl),
7.55-7.57 (m, 2 H, H-5, -6 of phenylene), 7.62-7.66 (m, 3 H,
H-4 of phenylene and H-2′′, -6′′ of phenyl), 7.79 (s, 1 H, H-2 of
phenylene), 7.93 (d, 1 H, J ) 8.0 Hz, H-4′ of pyridyl), 8.62 (dd,
1 H, J ) 1.2, 4.9 Hz, H-6′ of pyridyl), 8.91 (d, 1 H, J ) 1.9 Hz,
H-2′ of pyridyl); 13C NMR (100 MHz, CDCl3) 123.6, 126.05,
126.08, 126.9, 127.2, 127.6, 128.3, 128.9, 129.5, 134.4, 136.6,
138.4, 140.8, 142.2, 148.4, 148.6. Anal. Calcd for C17H13N: C,
88.28; H, 5.67; N, 6.06. Found: C, 88.44; H, 5.67; N, 6.21.
3-[3′-(Dieth ylbor yl)p h en yl]p yr id in e (4). To an ethereal
solution (4 mL) of 7 (406 mg, 1.736 mmol) and TMEDA (260
µL, 1.723 mmol) was added dropwise a hexane solution of
n-butyllithium (1.55 M, 1.23 mL, 1.907 mmol) at -78 °C over
2 min, and the whole was stirred for 1 h. To this was added a
THF solution of diethylmethoxyborane (1.0 M, 5.3 mL, 5.3
mmol) at -78 °C, and the mixture was stirred for 1 h. After
being warmed to 0 °C, the mixture was stirred for additional
0.5 h, diluted with ethyl acetate (40 mL), washed with water
(15 mL) and brine (5 mL × 2), and dried over MgSO4. After
removal of the solvent, the residue was chromatographed on
deactivated (5% H2O) silica gel (4 g) with a mixture of benzene
and hexane (1:1) as an eluent to give 4 (248 mg, 61.0%): faint
yellow solid; mp 66-74 °C; IR (KBr) 2864, 1615, 1582, 1470,
1429, 1383, 1262 cm-1; EI-MS (20 eV) 418 (13%, 2M+ - Et +
1), 223 (34, M+), 194 (100, M+ - Et), 166 (95); ES-MS (LiCl in
THF, negative mode) 926.4 (6, [4M + Cl]-), 703.1 (6, [3M +
1
Cl]-), 480.8 (8, [2M + Cl]-), 258.1 (100, [M + Cl]-); H NMR
(500 MHz, acetone-d6) major component 0.60 [t, J ) 7.5 Hz,
-B(CH2CH3)2], 0.73-0.87 [m, -B(CH2CH3)2], 7.29-7.49 (m,
4H), 7.80 (dd, J ) 5.8, 7.6 Hz, H-5 of pyridyl), 8.34 (d, J ) 7.4
Hz, H-4 of pyridyl), 8.43 (s, H-2 of pyridyl), 8.61 (d, J ) 5.5
Hz, H-6 of pyridyl); minor componemt 0.49-0.56 [m, -B(CH2-
CH3)2], 0.73-0.87 [m, -B(CH2CH3)2], 7.29-7.49 (m, 4 H), 7.77
(dd, J ) 5.8, 7.6 Hz, H-5 of pyridyl), 8.32 (d, J ) 7.4 Hz, H-4
of pyridyl), 8.43 (s, H-2 of pyridyl), 8.49 (d, J ) 5.9 Hz, H-6 of
3-[4′-(Dieth ylbor yl)p h en yl]-5-m eth oxyp yr id in e (10): IR
(KBr) 2865, 1590, 1456, 1331, 1223 cm-1; 1H NMR (400 MHz,
toluene-d8) major component 0.74-1.22 [m, -B(CH2CH3)2],
3.14 (s, -OCH3), 7.01 (s, H-4 of pyridyl), 7.04 (d, J ) 8.1 Hz,
H-2′, -6′ of phenylene), 7.44 (d, J ) 8.1 Hz, H-3′, -5′ of
phenylene), 8.02 (s, H-2 of pyridyl), 8.30 (d, J ) 2.7 Hz, H-6 of
pyridyl); minor component 0.74-1.28 [m, -B(CH2CH3)2], 3.03
(s, -OCH3), 7.10 (s, H-4 of pyridyl), 7.25 (d, J ) 8.1 Hz, H-2′,
1
pyridyl); H NMR (toluene-d8, 600 MHz) one component 0.93