Seganish and DeShong
2-(Tr ieth oxysilyl)p h en yl N,N-d ieth ylca r ba m a te (Ta ble
1, en tr y 3). Title compound was synthesized by a modified
metalation procedure of Snieckus and co-workers.16 A solution
of O-phenyl diethylcarbamate (0.966 g, 5.00 mmol) in 5 mL of
THF was added dropwise to a stirred solution of sec-BuLi (4.01
mL, 5.50 mmol) and TMEDA (0.830 mL, 5.50 mmol) in 50 mL
of THF at -78 °C. The reaction was stirred for 1 h at -78 °C
and was then slowly added to a stirred solution of tetraethyl
orthosilicate (3.35 mL, 15.0 mmol) in 30 mL of THF at -78
°C. The reaction was stirred at -78 °C for 2 h, followed by 2
h at room temperature. Saturated aqueous NH4Cl (50 mL) was
added to the reaction mixture. The aqueous layer was then
extracted with ether (50 mL × 2) and dried (MgSO4), and the
solvent was removed in vacuo to give a dark yellow oil.
Kugelrohr distillation (135 °C, 0.9 mmHg) yielded pure silox-
ane as a colorless oil (57%). IR (CCl4) 2978 (w), 2929 (w), 2885
(w), 1718 (s), 1421 (m), 1200 (m), 1155 (s), 1103 (s), 1086 (s);
1H NMR (CDCl3) δ 1.19-1.28 (m, 15H), 3.38 (q, J ) 7.2 Hz,
2H), 3.53 (q, J ) 7.2 Hz, 2H), 3.82 (q, J ) 7.2 Hz, 6H), 7.17-
7.26 (m, 2H), 7.43-7.45 (m, 1H), 7.71-7.30 (m, 1H); 13C NMR
(CDCl3) δ 13.3, 14.0, 18.0, 41.6, 42.0, 58.4, 122.4, 122.9, 124.6,
131.7, 137.0, 154.0, 156.5; LRMS (EI+) m/z 355 (M+, 5), 309
(30), 100 (100), 72 (25); HRMS (EI+, M+) m/z calcd for C17H29O5-
NSi 355.1815, found 355.1822.
2-(Tr ieth oxysilyl)p iva la n ilid e (Ta ble 1, en tr y 4). Piv-
alanilide (886 mg, 5.00 mmol) was dissolved in a 50:50 solution
of THF/Et2O. To this colorless solution at 0 °C was added 12.4
mL of a 1.21 M solution of n-BuLi in hexane (15.0 mmol). The
pale yellow solution was stirred at 25 °C for 20 h. The resulting
white slurry was cooled to 0 °C and diluted with 50 mL of THF.
Tetraethyl orthosilicate (3.35 mL, 15.0 mmol) was then added
via syringe. The reaction was stirred for a further 4 h at room
temperature. The solvent was removed in vacuo and the
residue was dissolved in ether. The ether was washed with
saturated aqueous NH4Cl (50 mL) twice and dried (MgSO4),
and the solvent was removed in vacuo to give a pale yellow
oil. Column chromatography (9:1 hexanes/EtOAc, TLC Rf )
0.28) yielded a pale yellow oil (62%). IR (CCl4) 3368 (s), 3054
(w), 2971 (s), 2922 (s), 2895 (s), 1683 (s), 1576 (s), 1535 (s),
1431 (s), 1300 (s), 1159 (s), 1103 (s), 1076 (s), 962 (s); 1H NMR
(CDCl3) δ 1.24 (t, J ) 8.0 Hz, 9H), 1.30 (s, 9H), 3.88 (q, J )
8.0 Hz, 6H), 7.07 (t, J ) 8.0 Hz, 1H), 7.41 (m, 1H), 7.55 (m,
1H), 8.33 (d, J ) 8.4 Hz, 1H), 8.99 (s, 1H); 13C NMR (CDCl3)
δ 18.1, 27.6, 39.8, 59.1, 119.1, 121.0, 123.2, 131.7, 135.6, 144.1,
177.0; LRMS (FAB+) m/z 339 (M+, 10), 294 (100); HRMS
(FAB+, M+) m/z calcd for C17H29O4NSi 339.1866, found 339.1860.
2-(Tr ieth oxysilyl)-N-(ter t-bu toxycar bon yl)an ilin e (Table
1, en tr y 5). A solution of t-BuLi (4.20 mL, 6.30 mmol) was
added dropwise to a stirred, colorless solution of N-(tert-
butoxycarbonyl)aniline (500 mg, 2.52 mmol) in 10 mL of THF.
The yellow solution was stirred at -20 °C for 2 h. The solution
was diluted with 20 mL of THF and cooled to -78 °C, and
tetraethyl orthosilicate (1.69 mL, 7.56 mmol) was then added
via syringe. The reaction was then allowed to warm to room
temperature overnight and quenched with saturated aqueous
NH4Cl (50 mL). The aqueous layer was then extracted with
ether (50 mL × 2), decolorized with activated carbon, and dried
(MgSO4), and the solvent was removed in vacuo to give a dark
yellow oil. Column chromatography (9:1 hexanes/EtOAc, TLC
Rf ) 0.33) yielded a colorless oil (61%). IR (CCl4) 3337 (m),
3054 (w), 2978 (s), 2926 (m), 2888 (m), 1725 (s), 1580 (m), 1535
(m), 1438 (m), 1369 (m), 1300 (m), 1159 (s), 1079 (s), 958 (m);
1H NMR (CDCl3) δ 1.27 (t, J ) 6.8 Hz, 9H), 1.51 (s, 9H), 3.89
(q, J ) 6.8 Hz, 6H), 7.01 (t, J ) 7.6 Hz, 1H), 7.38-7.42 (m,
1H), 7.49-7.51 (m, 1H), 8.12 (d, J ) 8.4 Hz, 1H), 8.72 (s, 1H);
13C NMR (CDCl3) δ 18.0, 28.4, 29.5, 59.0, 118.6, 122.0, 131.8,
135.5, 144.7, 153.1; LRMS (FAB+) m/z 355 (M+, 42), 310 (22),
299 (40), 254 (100), 210 (45), 57 (25); HRMS (FAB+, M+) m/z
calcd for C17H29O5NSi 355.1815, found 355.1826.
2-(Dieth ylca r ba m oyl)ben zop h en on e (Ta ble 1, en tr y 6).
N,N-Diethylbenzamide (500 mg, 2.82 mmol) in 20 mL of THF
was added slowly to a solution of sec-BuLi (2.38 mL, 3.10
mmol) and TMEDA (0.468 mL, 3.10 mmol) in 40 mL of THF
at -78 °C. The reaction was stirred at -78 °C for 1 h. The
reaction mixture was then added to Si(OEt)4 (1.89 mL, 8.46
mmol) in 100 mL of THF at -78 °C. The reaction was stirred
for 1 h at -78 °C and quenched with saturated aqueous NH4Cl
(100 mL). The aqueous layer was then extracted with ether
(50 mL × 2) and dried (MgSO4), and the solvent was removed
in vacuo to give a dark yellow oil. Column chromatography
(1:1 hexanes/EtOAc, TLC Rf ) 0.29) yielded a white solid
(95%), mp 76.8-77.2 °C (lit. 76-77 °C).17 IR (neat) 3059 (w),
2975 (w), 2935 (w), 2866 (w), 1660 (m), 1620 (s), 1591 (m), 1428
(m), 1268 (s), 1083 (m), 927 (m); 13C NMR (CDCl3) δ 12.2, 13.7,
38.8, 43.2, 126.8, 128.1, 128.3, 129.8, 130.3, 130.7, 133.0, 137.0,
137.2, 138.8, 169.9, 196.7; LRMS (FAB+) m/z 282 (M+, 95), 209
(100), 105 (32), 72 (32), 57 (19); HRMS (FAB+, M+) m/z calcd
for C18H20O2N 282.1499, found 282.1507. The 1H NMR matches
that reported by Snieckus and co-workers.17
N,N-Dieth yl-o-tolu a m id e (Ta ble 1, en tr y 7). Title com-
pound was synthesized by a modified metalation procedure of
Beak and Brown.18 N,N-Diethylbenzamide (570 mg, 3.22
mmol) in 10 mL of THF was added slowly to a solution of sec-
BuLi (2.58 mL, 3.53 mmol) and TMEDA (0.533 mL, 3.53 mmol)
in 40 mL of THF at -78 °C. The reaction was stirred at -78
°C for 1 h. Methyl iodide (0.501 mL, 8.05 mmol) was then
added via syringe. The solution was then allowed to warm to
room temperature. The reaction was quenched with saturated
aqueous NH4Cl (50 mL). The aqueous layer was then extracted
with ether (50 mL × 2) and dried (MgSO4), and the solvent
was removed in vacuo to give a dark yellow oil. Kugelrohr
distillation (85 °C, 0.3 mmHg) yielded the title compound as
a colorless oil (85%). IR (CCl4) 3061 (w), 3026 (w), 2974 (w),
2933 (w), 2871 (w), 1635 (s), 1552 (m), 1473 (m), 1455 (m),
1428 (m); 13C NMR (CDCl3) δ 12.9, 14.0, 18.8, 38.7, 42.6, 125.4,
125.8, 128.5, 130.3, 133.8, 137.1, 170.8. The 1H NMR spectrum
matches that reported by Beak and Brown.18
P a lla d iu m -Ca t a lyzed Cr oss-Cou p lin g R ea ct ion s of
Ar yl Siloxa n es w ith Ar yl Br om id es, Rep r esen ta tive
P r oced u r e. To a solution of siloxane (1.5 mmol), aryl bromide
(1.0 mmol), Pd(OAc)2 (0.10 mmol), and PPh3 (0.20 mmol) in
DMF (10 mL) is added 1.5 mL of TBAF in THF (1.0 M solution,
1.5 mmol). The reaction is heated at 90 °C for 4 h. The reaction
is poured into 25 mL of water, and the aqueous layer is
extracted with ether (25 mL ×3). The combined organic layers
are dried (MgSO4) and concentrated in vacuo. The biaryl
product is then purified via column chromatography.
2-Meth oxybip h en yl (Ta ble 3, en tr y 1). Column chroma-
tography (19:1 hexanes/EtOAc, TLC Rf ) 0.37) yielded a
1
colorless oil (39%). The H and 13C NMR and IR spectra match
those reported by Buchwald and co-workers.19
4′-Meth oxy-2-(N,N-dieth yl-O-car bam oyl)biph en yl (Table
3, en tr y 2). Column chromatography (4:1 hexanes/EtOAc, TLC
Rf ) 0.27) yielded a colorless oil contaminated with a small
amount of hexanes (12%): IR (CCl4) 3078 (w), 3036 (w), 2971
(w), 2926 (w), 2867 (w), 2829 (w), 1718 (s), 1555 (m), 1521 (m),
1417 (m), 1272 (m), 1248 (m), 1196 (m), 1155 (m); 1H NMR
(CDCl3) δ 1.04 (t, J ) 6.5 Hz, 6H), 3.26 (q, J ) 6.5 Hz, 4H),
3.83 (s, 3H), 6.92 (d, J ) 8.0 Hz, 2H), 7.18-7.36 (m, 6H); 13C
NMR (CDCl3) δ 13.9, 13.2, 41.6, 41.9, 55.3, 113.5, 123.2, 125.5,
127.9, 130.2, 130.5, 134.7, 148.5, 154.1, 158.8; LRMS (EI+) m/z
299 (M+, 78), 294 (23), 100 (100), 72 (21); HRMS (EI+, M+)
m/z calcd for C18H21O3NSi 299.1521, found 299.1518.
2-Meth oxym eth oxybip h en yl (Ta ble 3, en tr y 3). Column
chromatography (19:1 hexanes/EtOAc, TLC Rf ) 0.28) yielded
a colorless oil (54%): IR (CCl4) 3061 (w), 3026 (w), 2992 (w),
(17) Sibi, M. P.; Miah, M. A. J .; Snieckus, V. J . Org. Chem. 1984,
49, 737-742.
(18) Beak, P.; Brown, R. A. J . Org. Chem. 1982, 47, 34-46.
(19) Wolfe, J . P.; Singer, R. A.; Yang, B. H.; Buchwald, S. L. J . Am.
Chem. Soc. 1999, 121, 9550-9561.
(16) Sibi, M. P.; Chattopadhyay, S.; Dankwardt, J . W.; Snieckus,
V. J . Am. Chem. Soc. 1985, 107, 6312-6315.
6794 J . Org. Chem., Vol. 69, No. 20, 2004