Synthesis
Feature Article
Using general procedure B, 5 (112 mg, 0.60 mmol), nBuLi (2.2 M in
hexane, 0.28 mL, 0.63 mmol) and KOtBu (1M in THF, 0.63 mL, 0.63 mmol)
in THF (1.7 mL) were treated with imine 2i (112 mg, 0.50 mmol) in THF
(2.4 mL) to give 1,3-diene 6i (103 mg, 0.44 mmol, 89%) as a colourless oil
after purification by flash column chromatography (eluent: hexane-
EtOAc, 95:5). Spectral data in accordance to previously published data.26
Using general procedure B, 5 (170 mg, 0.91 mmol), nBuLi (2.2 M in
hexane, 0.43 mL, 0.95 mmol) and KOtBu (1M in THF, 0.95 mL, 0.95 mmol)
in THF (2.6 mL) were treated with imine 2m (130 mg, 0.76 mmol) in THF
(3.7 mL) to give 1,3-diene 6m (135 mg, 0.70 mmol, 92%) as a pale yellow
oil after purification by flash column chromatography (eluent: hexane).
Rf (hexane) = 0.35.
Rf (hexane-EtOAc, 90:10) = 0.77.
IR (ATR): 2955, 1592, 1247, 996, 850, 833 cm–1
.
1H NMR (400 MHz, CDCl3); 7.23 (t, J = 7.8 Hz, 1H), 7.00 (d, J = 7.8 Hz, 1H),
6.95–6.93 (m, 1H), 6.81–6.74 (m, 2H), 6.67 (dd, J = 17.9, 10.1 Hz, 1H), 6.55
(d, J = 15.3 Hz, 1H), 6.01 (d, J = 17.9 Hz, 1H), 3.82 (s, 3H), 0.12 (s, 9H).
1H NMR (400 MHz, CDCl3); 7.37 (d, J = 1.7 Hz, 1H), 6.73–6.57 (m, 2H),
6.39–6.29 (m, 3H), 5.99 (d, J = 17.6 Hz, 1H), 0.11 (s, 9H).
13C NMR (101 MHz, CDCl3); 153.2, 143.7, 142.4, 135.3, 130.3, 120.4,
111.8, 109.0, −1.1.
13C NMR (101 MHz, CDCl3); 159.9, 144.1, 138.8, 135.4, 132.9, 132.1,
129.7, 119.4, 113.5, 111.8, 55.3, −1.1.
HRMS (ESI and APCI): target not found.
Trimethyl[(1E,3E)-4-(2-methoxyphenyl)buta-1,3-dien-1-yl]silane (6j)
Trimethyl{(1E,3E)-4-[4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-
yl)phenyl]buta-1,3-dien-1-yl}silane (6n)
Using general procedure B, 5 (112 mg, 0.60 mmol), nBuLi (2.2 M in
hexane, 0.28 mL, 0.63 mmol) and KOtBu (1M in THF, 0.63 mL, 0.63 mmol)
in THF (1.7 mL) were treated with imine 2j (106 mg, 0.50 mmol) in THF
(2.4 mL) to give 1,3-diene 6j (97 mg, 0.42 mmol, 83%) as a colourless oil
after purification by flash column chromatography (eluent: hexane-
EtOAc, 95:5).
Using general procedure B, 5 (47 mg, 0.25 mmol), nBuLi (2.2 M in hexane,
0.12 mL, 0.26 mmol) and KOtBu (1M in THF, 0.26 mL, 0.26 mmol) in THF
(0.7 mL) were treated with imine 2n (65 mg, 0.21 mmol) in THF (1.0 mL)
to give 1,3-diene 6n (56 mg, 0.17 mmol, 81%) as a yellow oil after
purification by flash column chromatography (eluent: hexane).
Rf (hexane-EtOAc, 90:10) = 0.65.
Rf (hexane-EtOAc, 95:5) = 0.52.
IR (ATR): 2954, 1242, 1000, 866, 833, 746 cm–1
.
IR (ATR): 2980, 2986, 1357, 834 cm–1
.
1H NMR (400 MHz, CDCl3); 7.47 (dd, J = 7.7, 1.6 Hz, 1H), 7.24–7.20 (m,
1H), 6.96–6.91 (m, 2H), 6.88–6.69 (m, 3H), 5.97 (d, J = 17.4 Hz, 1H), 3.86
(s, 3H), 0.11 (s, 9H).
1H NMR (400 MHz, CDCl3); 7.75 (d, J = 8.1 Hz, 2H), 7.40 (d, J = 8.1 Hz, 2H),
6.85 (dd, J = 15.5, 10.1 Hz, 1H), 6.68 (dd, J = 18.2, 10.1 Hz, 1H), 6.58 (d, J =
15.5 Hz, 1H), 6.03 (d, J = 18.2 Hz, 1H), 1.34 (s, 12H), 0.11 (s, 9H).
13C NMR (101 MHz, CDCl3); 157.0, 145.1, 134.2, 132.4, 128.8, 127.8,
126.6, 120.8, 111.0, 55.6, −1.1.
13C NMR (101 MHz, CDCl3); 144.1, 140.0, 136.0, 135.2, 132.9, 132.7,
125.9, 83.9, 25.0, −1.2.
HRMS (APCI): m/z [M+H]+ calcd for C14H20OSi: 233.1356; found:
233.1361.
HRMS (APCI): m/z [M+H]+ calcd for C19H29BO2Si: 328.2103; found:
328.2139.
Trimethyl[(1E,3E)-4-(naphthalen-2-yl)buta-1,3-dien-1-yl]silane (6k)
Trimethyl[(1E)-4,4-diphenylbuta-1,3-dien-1-yl]silane (6o)
Using general procedure B, 5 (112 mg, 0.60 mmol), nBuLi (2.2 M in
hexane, 0.28 mL, 0.63 mmol) and KOtBu (1M in THF, 0.63 mL, 0.63 mmol)
in THF (1.7 mL) were treated with imine 2k (116 mg, 0.50 mmol) in THF
(2.4 mL) to give 1,3-diene 6k (102 mg, 0.40 mmol, 81%) as a colourless
solid after purification by flash column chromatography (eluent: hexane).
Spectral data in accordance to previously published data.26,47
Using general procedure B, 5 (112 mg, 0.60 mmol), nBuLi (2.2 M in
hexane, 0.28 mL, 0.63 mmol) and KOtBu (1M in THF, 0.63 mL, 0.63 mmol)
in THF (1.7 mL) were treated with benzophenone (91 mg, 0.50 mmol) in
THF (2.4 mL) to give 1,3-diene 6o (111 mg, 0.40 mmol, 80%) as a yellow
oil after purification by flash column chromatography (eluent: hexane-
EtOAc, 99:1).
Rf (hexane) = 0.38.
Rf (hexane-CH2Cl2, 90:10) = 0.54.
1H NMR (400 MHz, CDCl3); 7.81–7.77 (m, 3H), 7.75 (s, 1H), 7.63 (dd, J =
8.6, 1.6 Hz, 1H), 7.48–7.41 (m, 2H), 6.92 (dd, J = 15.5, 10.1 Hz, 1H), 6.78–
6.71 (m, 2H), 6.06 (d, J = 18.3 Hz, 1H), 0.14 (s, 9H).
IR (ATR): 2953, 1699, 1246, 834 cm–1
.
1H NMR (400 MHz, CDCl3); 7.40–7.20 (m, 10H), 6.69–6.59 (m, 2H), 6.06
(d, J = 16.9 Hz, 1H), 0.01 (s, 9H).
13C NMR (101 MHz, CDCl3); 144.2, 135.4, 134.9, 133.8, 133.2, 133.1,
132.2, 128.4, 128.1, 127.8, 126.8, 126.4, 126.1, 123.6, −1.1.
13C NMR (101 MHz, CDCl3); 143.1, 142.5, 141.9, 139.8, 136.4, 130.8,
130.6, 128.3, 128.2, 127.9, 127.6, 127.6, −1.2.
HRMS (APCI): m/z [M+H]+ calcd for C19H22Si: 279.1564; found: 279.1558.
Trimethyl[(1E,3E)-4-(thiophen-2-yl)buta-1,3-dien-1-yl]silane (6l)
Using general procedure B, 5 (179 mg, 0.96 mmol), nBuLi (2.2 M in
hexane, 0.45 mL, 1.00 mmol) and KOtBu (1M in THF, 1.0 mL, 1.00 mmol)
in THF (2.8 mL) were treated with imine 2l (150 mg, 0.80 mmol) in THF
(3.9 mL) to give 1,3-diene 6l (131 mg, 0.63 mmol, 78%) as a colourless oil
after purification by flash column chromatography (eluent: hexane).
Spectral data in accordance to previously published data.47
tert-Butyl 4-[(2E)-3-(trimethylsilyl)prop-2-en-1-ylidene]piperidine-1-
carboxylate (6p)
Using general procedure B, 5 (134 mg, 0.72 mmol), nBuLi (2.2 M in
hexane, 0.34 mL, 0.75 mmol) and KOtBu (1M in THF, 0.75 mL, 0.75 mmol)
in THF (2.1 mL) were treated with N-Boc piperidone (119 mg, 0.60 mmol)
in THF (2.9 mL) at −78 °C to give 1,3-diene 6p (23 mg, 0.08 mmol, 13%)
as a pale yellow sticky solid and recovered N-Boc piperidone (77 mg, 0.39
mmol, 64%) after purification by flash column chromatography (eluent:
hexane-EtOAc, 95:5).
Rf (hexane) = 0.53.
1H NMR (400 MHz, CDCl3); 7.17 (d, J = 4.6 Hz, 1H), 6.99–6.96 (m, 2H),
6.72–6.56 (m, 3H), 6.02– 5.93 (m, 1H), 0.11 (s, 9H).
13C NMR (101 MHz, CDCl3); 143.6, 142.7, 135.1, 131.5, 127.7, 126.4,
125.8, 124.8, −1.1.
Rf (hexane-EtOAc, 80:20) = 0.52.
IR (ATR): 2951, 1701 (C=O), 1422, 1234, 835 cm–1
.
1H NMR (400 MHz, CDCl3); 6.76 (dd, J = 18.2, 10.5 Hz, 1H), 5.92 (d, J =
10.5 Hz, 1H), 5.81 (d, J = 18.2 Hz, 1H), 3.46–3.40 (m, 4H), 2.42–2.37 (m,
2H), 2.22–2.17 (m, 2H), 1.46 (s, 9H), 0.08 (s, 9H).
Trimethyl[(1E,3E)-4-(furan-2-yl)buta-1,3-dien-1-yl]silane (6m)
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2021-04-22
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