A. M. Gonz aꢀ lez-Nogal et al. / Tetrahedron 63 (2007) 224–231
229
3
.2.6. trans-1-tert-Butyldiphenylsilyl-4-carbomethoxy-5-
Anal. Calcd for C H O Si : C, 70.19; H, 8.34. Found: C,
24 34 2 2
trimethylsilyl-2-pyrazoline (8a). Yield 28%; oil, R ¼0.26
70.38; H, 8.52.
f
(
CH Cl –hexane, 1:1); IR (film) 1731, 1616, 1471, 1250,
2 2
ꢀ
1 1
1
9
6
106 cm ; H NMR (CDCl ) d ꢀ0.35 (s, 9H), 1.00 (s,
3.2.12. E-3-tert-Butyldiphenylsilyl-5-trimethylsilylpent-
4-en-2-one (10b). Yield 40%; oil, R ¼0.64 (CH Cl –hex-
3
H), 3.68 (dd, J¼1.9, 5.0 Hz, 1H), 3.98 (d, J¼5.0 Hz, 1H),
.71 (d, J¼1.9 Hz, 1H), 7.34–7.46 (m, 6H), 7.83 (m, 4H);
C NMR d ꢀ3.84, 20.81, 27.78, 52.28, 53.05, 53.54,
27.32, 127.79, 129.55, 129.68, 134.00, 134.24, 135.63,
35.94, 136.20, 171.71. Anal. Calcd for C H N O Si :
f
2
2
ꢀ
1
ane, 1:1); IR (film) 1713, 1605, 1496, 1250, 1105 cm
H NMR (CDCl ) d 0.01 (s, 9H), 1.04 (s, 9H), 1.91 (s,
;
1
3
1
3
1
1
3H), 5.30 (d, J¼18.1 Hz, 1H), 5.39 (d, J¼10.5 Hz, 1H),
6.46 (dd, J¼10.6, 18.1 Hz, 1H), 7.36–7.44 (m, 6H), 7.71
2
4
34
2
2
2
1
3
C, 65.71; H, 7.81; N, 6.39. Found: C, 65.34; H, 7.99; N, 6.58.
(m, 4H); C NMR d ꢀ0.06, 19.67, 20.56, 27.79, 115.17,
128.56, 128.95, 131.05, 134.54, 136.63, 141.24, 204.00.
Anal. Calcd for C H OSi : C, 73.03; H, 8.68. Found: C,
72.88; H, 8.93.
3
.2.7. trans-4-Acetyl-1-tert-butyldiphenylsilyl-5-tri-
2
4
34
2
methylsilyl-2-pyrazoline (8b). Yield 25%; oil, R ¼0.15
f
(
1
9
hexane–AcOEt, 20:1); IR (film) 1712, 1600, 1491, 1250,
ꢀ
1 1
109 cm ; H NMR (CDCl ) d ꢀ0.37 (s, 9H), 0.96 (s,
3.2.13. E-3-Dimethylphenylsilyl-5-trimethylsilylpent-4-
en-2-one (10c). Yield 45%; oil, R ¼0.69 (CH Cl –hexane,
3
H), 2.26 (s, 3H), 3.67 (dd, J¼2.1, 5.0 Hz, 1H), 4.06 (d,
f
2
2
ꢀ
1
1
J¼5.0 Hz, 1H), 6.75 (d, J¼2.1 Hz, 1H), 7.38–7.45 (m,
1:1); IR (film) 1710, 1600, 1496, 1250, 1100 cm ; H
1
3
6
2
1
H), 7.73 (m, 2H), 7.82 (m, 2H); C NMR d ꢀ3.77,
0.79, 27.80, 28.01, 51.41, 62.41, 127.59, 129.29, 129.75,
33.51, 134.33, 134.76, 135.88, 136.46, 203.05. Anal. Calcd
NMR (CDCl ) d ꢀ0.32 (s, 9H), 0.97 (s, 9H), 2.26 (s, 3H),
3
2.37 (d, J¼13.0 Hz, 1H), 6.10 (d, J¼15.3 Hz, 1H), 7.40
(dd, J¼13.0, 15.3 Hz, 1H), 7.37–7.47 (m, 6H), 7.65 (m,
2H), 7.82 (m, 2H). Anal. Calcd for C H OSi : C, 66.14;
for C H N OSi : C, 68.19; H, 8.11; N, 6.63. Found: C,
2
4
34
2
2
16 26
2
6
7.96; H, 8.32; N, 6.85.
H, 9.02. Found: C, 66.31; H, 8.87.
3
.2.8. Methyl E-4-tert-butyldiphenylsilyl-4-trimethyl-
3.3. Cycloadditions with N-phenylsydnone: general
procedure
silylcrotonate (9a). Yield 27%; oil, R ¼0.26 (CH Cl –hex-
f
2
2
ꢀ
1 1
ane, 1:1); IR (film) 1731, 1616, 1471, 1250, 1106 cm ; H
NMR (CDCl ) d ꢀ0.33 (s, 9H), 0.96 (s, 9H), 2.37 (d,
A mixture of N-phenylsydnone (1.5 mmol) and the alkynes
1a, 1c–g or the alkenes 6a–d, 6g, 6i,j (1.5 mmol) in toluene
(5 mL) or decalin (5 mL) was stirred at reflux. At the end of
the reaction (monitored by TLC) the solvent was evaporated
under reduced pressure and the residue was extracted with
ether and washed with water. The organic layer was dried
3
J¼13.2 Hz, 1H), 3.76 (s, 3H), 5.80 (d, J¼15.0 Hz, 1H),
7
.40 (dd, J¼13.2, 15.0 Hz, 1H), 7.34–7.46 (m, 6H), 7.64–
1
3
7
5
1
.72 (m, 4H); C NMR d ꢀ0.60, 20.31, 25.12, 27.86,
1.21, 118.13, 127.55, 129.27, 133.28, 136.45, 151.67,
67.06. Anal. Calcd for C H O Si : C, 70.19; H, 8.34.
2
4
34
2
2
Found: C, 70.32; H, 8.18.
(MgSO ) and concentrated. The residue was purified by
4
flash chromatography on silica gel using as eluent
CH Cl –hexane (20:1–10:1) to give the following products:
3
.2.9. E-5-tert-Butyldiphenylsilyl-5-trimethylsilylpent-3-
2
2
en-2-one (9b). Yield 40%; oil, R ¼0.11 (CH Cl –hexane,
f
2
2
ꢀ
1
1
1
:1); IR (film) 1693, 1606, 1491, 1255, 1105 cm ; H
3.3.1. 3-Trimethylsilyl-1-phenylpyrazole (3a). Yield 95%;
oil, R ¼0.27 (CH Cl ); IR (film) 1600, 1510, 1445,
NMR (CDCl ) d ꢀ0.32 (s, 9H), 0.97 (s, 9H), 2.26 (s, 3H),
3
f
2
2
ꢀ1
1
2
.37 (d, J¼13.0 Hz, 1H), 6.10 (d, J¼15.3 Hz, 1H), 7.40
1250 cm ; H NMR (CDCl ) d 0.35 (s, 9H), 6.57 (d,
3
(
dd, J¼13.0, 15.3 Hz, 1H), 7.37–7.47 (m, 6H), 7.65 (m,
J¼2.1 Hz, 1H), 7.49 (t, J¼8.0 Hz, 1H), 7.62 (t, J¼8.0 Hz,
1
3
13
2
2
1
H), 7.82 (m, 2H); C NMR d ꢀ0.54, 20.35, 25.48,
6.95, 27.89, 127.37, 127.85, 129.34, 129.45, 129.63,
33.25, 133.82, 136.17, 136.37, 151.35, 197.26. Anal.
2H), 7.74 (d, J¼8.0 Hz, 2H), 7.93 (d, J¼2.1 Hz, 1H);
C
NMR d ꢀ0.99, 113.61, 119.74, 126.38, 129.38, 131.01,
+
140.41, 155.09; MS (EI) m/z 216 (M , 8%), 215 (25), 200
Calcd for C H OSi : C, 73.03; H, 8.68. Found: C, 72.87;
2
H, 8.41.
(20), 143 (10), 77 (52), 73 (100). Anal. Calcd for
C H N Si: C, 66.62; H, 7.45; N, 12.95. Found: C, 66.43;
H, 7.59; N, 13.15.
4
34
2
1
2 16 2
3
.2.10. E-5-Dimethylphenylsilyl-5-trimethylsilylpent-3-
en-2-one (9c). Yield 35%; oil, R ¼0.23 (CH Cl –hexane,
3.3.2. 4-Tributylstannyl-3-trimethylsilyl-1-phenylpyr-
azole (3c). Yield 80%; oil, R ¼0.21 (CH Cl ); IR (film)
f
2
2
ꢀ
1
1
1
:1); IR (film) 1690, 1600, 1496, 1255, 1105 cm ; H
f
1 1
2
2
ꢀ
NMR (CDCl ) d ꢀ0.32 (s, 9H), 0.97 (s, 9H), 2.26 (s, 3H),
1640, 1590, 1490, 1240 cm ; H NMR (CDCl ) d 0.07 (s,
3
3
2
.37 (d, J¼13.0 Hz, 1H), 6.10 (d, J¼15.3 Hz, 1H), 7.40
9H), 0.92 (t, J¼7.3 Hz, 9H), 1.43 (m, 12H), 1.68 (m, 6H),
+
(
dd, J¼13.0, 15.3 Hz, 1H), 7.37–7.47 (m, 6H), 7.65 (m,
7.33–7.56 (m, 5H), 8.22 (s, 1H); MS (EI) m/z 504 (M ,
2%), 489 (15), 448 (10), 431 (15), 213 (22), 105 (13), 77
(28), 73 (30), 57 (100). Anal. Calcd for C H N SiSn: C,
2
H, 9.02. Found: C, 66.36; H, 8.89.
H), 7.82 (m, 2H). Anal. Calcd for C H OSi : C, 66.14;
1
6
26
2
2
4 42 2
57.04; H, 8.38; N, 5.54. Found: C, 56.84; H, 8.53; N, 5.27.
3
.2.11. Methyl E-2-tert-butyldiphenylsilyl-4-trimethyl-
silylbut-3-enoate (10a). Yield 27%; oil, R ¼0.50 (CH Cl –
3.3.3. 3-Dimethylphenylsilyl-1-phenylpyrazole (3d).
Yield 75%; oil, R ¼0.26 (CH Cl ); IR (film) 1600, 1500,
f
2
2
ꢀ
1
hexane, 1:1); IR (film) 1730, 1600, 1471, 1248, 1105 cm
;
f
2
2
1
ꢀ1
1
H NMR (CDCl ) d ꢀ0.11 (s, 9H), 1.12 (s, 9H),
1460, 1250, 1100 cm ; H NMR (CDCl ) d 0.65 (s, 6H),
3
3
3
.52 (s, 3H), 3.65 (d, J¼9.7 Hz, 1H), 5.33 (d, J¼18.6 Hz,
H), 6.10 (dd, J¼9.7, 18.6 Hz, 1H), 7.36 (m, 6H), 7.66 (m,
6.58 (d, J¼2.0 Hz, 1H), 7.30 (t, J¼8.0 Hz, 1H), 7.32 (m,
13
1
4
1
3H), 7.47 (t, J¼8.0 Hz, 2H), 7.69 (m, 2H), 7.77 (d,
1
3
H); C NMR d ꢀ0.23, 20.97, 29.33, 46.53, 52.56,
J¼8.0 Hz, 2H), 7.96 (d, J¼2.0 Hz, 1H);
C NMR
d ꢀ2.29, 114.43, 119.58, 126.33, 126.86, 127.76, 129.11,
28.59, 130.65, 132.47, 133.70, 137.99, 141.71, 174.54.