7360
B.C.G. So¨derberg et al. / Tetrahedron 65 (2009) 7357–7363
obtained by chromatography. Elemental Analyses were performed
by Atlantic Microlab, Inc., Norcross, GA. High Resolution Mass
Spectra (HRMS) were performed at University of California River-
side Mass Spectrometry Center and in the C. Eugene Bennett De-
partment of Chemistry at West Virginia University.
and PdCl2(PPh3)2 (126 mg, 0179 mmol) in Et3N (20 mL), as de-
scribed for 5 (ambient temperature, 24 h) gave after workup and
chromatography (hexanes/EtOAc, 9:1), 8 (780 mg, 3.13 mmol, 87%)
as a yellow solid. Mp 66–68 ꢀC; 1H NMR
d
7.95 (d, J¼9.1 Hz,1H), 6.96
(d, J¼2.8 Hz, 1H), 6.82 (dd, J¼9.1, 2.8 Hz, 1H), 3.81 (s, 3H), 0.24 (s,
9H); 13C NMR
Compounds 1,19 2,20 24,21 26,20 27,20 28,22 29,23 30,20 36,24 have
previously been described and all spectral data (1H NMR, 13C NMR,
IR) are in complete accordance with literature values. Compounds
4,25 11 and 13,26 25,8 3127 have previously been described but
without spectroscopical data. A number of compounds (4, 14–20,
37) noticeably decomposed at ambient temperature thus, com-
bustion analysis or HRMS were not performed.
d
162.5 (þ), 142.6 (þ), 126.7 (ꢁ), 120.2 (þ), 119.0 (ꢁ),
114.4 (ꢁ), 103.2 (þ), 99.8 (þ), 55.8 (ꢁ), 0.59 (ꢁ); IR (neat) 2966,
2898, 2165, 1602 cmꢁ1; GC–MS (EI) m/z 249 (Mþ). Anal. Calcd for
C12H15NO3Si: C, 57.80; H 6.06; N, 5.62. Found: C, 57.97; H 6.31; N,
5.77.
4.6. 3-Methyl-2-nitro-1-[2-(trimethylsilyl)ethynyl]-
benzene (9)
4.2. 2,4-Dinitro-1-[2-(trimethylsilyl)ethynyl]benzene (5)
Reaction of 3-methyl-2-nitro-1-iodobenzene (500 mg, 1.90 mmol),
trimethylsilylethyne (205 mg, 2.09 mmol), CuI (27.0 mg, 0.143 mmol),
and PdCl2(PPh3)2 (67.0 mg, 0.095 mmol) in Et3N (20 mL), as described
for 5 (ambient temperature, 20 h) gave after workup and chromatog-
raphy (hexanes/EtOAc, 95:5), 9 (441 mg, 1.89 mmol, 99%) as a yellow
To
a
solution of 2,4-dinitro-1-bromobenzene (500 mg,
2.01 mmol) in triethylamine (Et3N, 15 mL) was added trimethylsi-
lylethyne (217 mg, 2.21 mmol), CuI (28.7 mg, 0.151 mmol), and
PdCl2(PPh3)2 (70.5 mg, 0.101 mmol). The reaction mixture was
stirred at ambient temperature under an argon atmosphere (24 h).
The solvent was removed under reduced pressure and the crude
product was purified by chromatography (hexanes/EtOAc, 9:1) to
give 5 (425 mg, 1.61 mmol, 80%) as a yellow solid. Mp 65–68 ꢀC; 1H
solid. Mp 39–41 ꢀC; 1H NMR
d
7.40 (dd, J¼7.5, 2.0 Hz, 1H), 7.31 (t,
J¼7.7 Hz, 1H), 7.24 (dd, J¼7.5, 1.6 Hz, 1H), 2.33 (s, 3H), 0.24 (s, 9H); 13C
NMR
d
153.1 (þ), 131.3 (ꢁ), 130.9 (ꢁ), 129.8 (þ), 129.8 (ꢁ), 116.2 (þ),
101.7 (þ), 97.7 (þ),17.4 (ꢁ), ꢁ0.50 (ꢁ); IR (neat) 2962, 2160,1600 cmꢁ1
;
GC–MS (EI) m/z 233 (Mþ), 73 (SiMeþ3 , 100%). Anal. Calcd for
C12H15NO2Si: C, 61.77; H 6.48; N, 6.00. Found: C, 62.28; H 6.64; N, 6.30;
HRMS calcd for C12H16NO2Si (MþHþ) 234.0950, found 234.0944.
NMR
d
8.88 (d, J¼2.3 Hz, 1H), 8.42 (dd, J¼8.5, 2.4 Hz, 1H), 7.84 (d,
J¼8.7 Hz, 1H), 0.31 (s, 9H); 13C NMR
149.9 (þ), 146.4 (þ), 136.2 (ꢁ),
d
124.2 (þ), 120.1 (ꢁ), 111.3 (þ), 97.6 (þ), ꢁ0.72 (ꢁ); IR (neat) 3092,
2962, 1594 cmꢁ1; GC–MS (EI) m/z 264 (Mþ), 249 (Mþꢁ15, 100%).
Anal. Calcd for C11H12N2O4Si: C, 49.99; H 4.58; N, 10.60. Found: C,
50.26; H 4.58; N, 10.38.
4.7. 6-Methyl-2-nitro-1-[2-(trimethylsilyl)ethynyl]-
benzene (11)
4.3. 4-Chloro-2-nitro-1-[2-(trimethylsilyl)ethynyl]benzene (6)
Reaction of 6-methyl-2-nitro-1-iodobenzene (1.30 g, 4.94 mmol),
trimethylsilylethyne (0.77 mL, 5.41 mmol), CuI (70.5 mg, 0.370 mmol),
and PdCl2(PPh3)2 (173 mg, 0.246 mmol) in Et3N (25 mL), as de-
scribed for 5 (50 ꢀC, 10 h) gave after workup and chromatography
(hexanes), 11 (1.02 g, 4.38 mmol, 89%) as a faint yellow oil. 1H NMR
Reaction
of
4-chloro-2-nitro-1-iodobenzene
(500 mg,
1.76 mmol), trimethylsilylethyne (191 mg, 1.94 mmol), CuI
(25.0 mg, 0.136 mmol), and PdCl2(PPh3)2 (62.0 mg, 0.088 mmol) in
Et3N (20 mL), as described for 5 (ambient temperature, 9 h) gave
(600 MHz)
d
7.76 (d, J¼8.4 Hz, 1H), 7.45 (d, J¼7.2 Hz, 1H), 7.30 (t,
after workup and chromatography (hexanes/EtOAc, 95:5)
(430 mg, 1.70 mmol, 97%) as a yellow solid. Mp 39–41 ꢀC; 1H NMR
7.92 (d, J¼2.0 Hz,1H), 7.53 (d, J¼8.3 Hz,1H), 7.46 (dd, J¼8.5, 2.0 Hz,
1H), 0.22 (s, 9H); 13C NMR
6
J¼8.1 Hz, 1H), 2.51 (s, 3H), 0.28 (s, 9H); 13C NMR (150 MHz)
d 151.0,
143.7, 133.6, 127.9, 121.6, 117.6, 108.5, 97.6, 21.2, ꢁ0.34; IR (neat)
2960, 1528, 1346, 1249 cmꢁ1; HRMS calcd for C12H16NO2Si (MþHþ)
234.0950, found 234.0946.
d
d
150.2 (þ), 135.8 (ꢁ), 134.5 (þ), 132.8
(ꢁ), 124.6 (ꢁ), 116.7 (þ), 105.0 (þ), 98.2 (þ), ꢁ0.57 (ꢁ); IR (neat)
3096, 2961, 2164 cmꢁ1; GC–MS (EI) m/z 253 (Mþ), 238 (Mþꢁ15), 73
(SiMeþ3 , 100%). Anal. Calcd for C11H12ClNO2Si: C, 52.06; H 4.77; N,
5.52. Found: C, 52.37; H 4.86; N, 5.87.
4.8. 3-Nitro-1-[2-(trimethylsilyl)ethynyl]pyridine (13)
Reaction of 2-chloro-3-nitropyridine (750 mg, 4.73 mmol), tri-
methylsilylethyne (511 mg, 5.20 mmol), CuI (68.0 mg, 0.355 mmol),
and PdCl2(PPh3)2 (166 mg, 0.237 mmol) in Et3N (15 mL), as de-
scribed for 5 (ambient temperature, 48 h) gave after workup and
chromatography (hexanes/EtOAc, 9:1), 13 (682 mg, 3.10 mmol,
4.4. 4-Methoxy-2-nitro-1-[2-(trimethylsilyl)ethynyl]-
benzene (7)
Reaction of 4-methoxy-2-nitro-1-iodobenzene (500 mg,1.79 mmol),
trimethylsilylethyne (194 mg,1.97 mmol), CuI (26.0 mg, 0.134 mmol),
and PdCl2(PPh3)2 (62.8 mg, 0.090 mmol) in Et3N (20 mL), as de-
scribed for 5 (ambient temperature, 22 h) gave after workup and
chromatography (hexanes/EtOAc, 95:5), 7 (410 mg,1.65 mmol, 92%)
66%) as a brown solid. Mp 36–38 ꢀC; 1H NMR
d
8.81 (dd, J¼4.8,
1.6 Hz, 1H), 8.34 (dd, J¼8.3, 1.6 Hz, 1H), 7.47 (dd, J¼8.3, 4.7 Hz, 1H),
0.33 (s, 9H); 13C NMR
d
153.2 (ꢁ), 147.2 (þ), 136.6 (þ), 132.2 (ꢁ),
123.0 (ꢁ), 105.1 (þ), 98.7 (þ), ꢁ0.33 (ꢁ); IR (neat) 2962, 2160, 1591,
1527 cmꢁ1; GC–MS (EI) m/z 220 (Mþ), 73 (SiMeþ3 , 100%).
as a yellow solid. Mp 69–71 ꢀC; 1H NMR
d
7.49 (d, J¼8.7 Hz,1H), 7.43
(d, J¼2.6 Hz, 1H), 7.46 (dd, J¼8.7, 2.8 Hz, 1H), 3.83 (s, 3H), 0.22 (s,
9H); 13C NMR
d
159.5 (þ), 150.9 (þ), 135.9 (ꢁ), 119.2 (ꢁ), 110.3 (þ),
4.9. 2-Nitro-1-[2-bromoethynyl]benzene (1)
109.2 (ꢁ), 101.0 (þ), 99.4 (þ), 55.8 (ꢁ), ꢁ0.40 (ꢁ); IR (neat) 2161,
1620, 1530 cmꢁ1; GC–MS (EI) m/z 249 (Mþ), 234 (Mþꢁ15, 100%).
Anal. Calcd for C12H15NO3Si: C, 57.80; H 6.06; N, 5.62. Found: C,
58.39; H 6.55; N, 5.30; HRMS calcd for C12H16NO3Si (MþHþ)
250.0899, found 250.0894.
To a solution of 1-(2,2-dibromoethenyl)-2-nitrobenzene28 (75 mg,
0.24 mmol) in DMF (3 mL) was added cesium carbonate (160 mg,
0.49 mmol) and the reaction mixture was stirred (ambient temp,
4 h). Dichloromethane (30 mL) was added, the organic phase was
washed with water (3ꢂ30 mL), dried (MgSO4), filtered, and the
solvents were removed under reduced pressure. The crude product
was purified by chromatography (hexanes/EtOAc, 9:1) affording 1
(52 mg, 0.24 mmol, 98%) as a yellow solid. Mp 98–100 ꢀC (lit.19 94–
95 ꢀC).
4.5. 2-(5-Methoxy-2-nitrophenyl)-1-trimethylsilylethyne (8)
Reaction of 5-methoxy-2-nitro-1-iodobenzene (1.00 g, 3.58 mmol),
trimethylsilylethyne (387 mg, 3.97 mmol), CuI (51.0 mg, 0.269 mmol),