10.1002/ejoc.201900726
European Journal of Organic Chemistry
FULL PAPER
(20 mL). After extraction with pentane (330 mL), the combined organic
layer was dried over MgSO4, and the solvent was removed under reduced
pressure. The residue was purified by flash chromatography over silica gel
(pentane) to afford -trimethylsilylstyrene (2e, 2.05 g, 68%) as a colorless
1423, 1329, 1309, 1246, 1115, 1083, 1030, 988, 830, 749, 688 cm−1. ESI–
MS (+10 V): m/z = 157.0 [M−OH]+, 192.0 [M+NH4]+, 197.1 [M+Na]+. HRMS:
calcd. for C8H18NaO2Si+ [M+Na]+ 197.0968; found 197.0972. 1H NMR
analysis matched previously reported data,[28] while 13C analysis showed
significant differences to the reported data.[21]
1
liquid. Rf = 0.64 (pentane). H NMR (300 MHz, CDCl3): = 0.17 (s, 9 H),
5.61 (d, J = 2.8 Hz, 1 H), 5.82 (d, J = 3.0 Hz, 1 H), 7.14–7.35 (m, 5 H) ppm.
13C NMR (75 MHz, CDCl3): = −0.75 (q), 126.36 (d), 126.85 (d), 127.30
(t), 128.25 (d), 144.93 (s), 153.65 (s) ppm. IR (ATR): = 3056, 3025, 2956,
2893, 1944, 1871, 1598, 1490, 1405, 1248, 1071, 1028, 931, 855, 833,
775, 757, 697 cm−1. GC–MS: m/z (%) = 176 (81) [M]+, 161 (100) [M−Me]+,
145 (35), 135 (95), 103 (37) [M−TMS]+, 77 (35), 73 (75) [TMS]+. The
spectra matched previously reported data.[29]
1-(Trimethylsilyl)cycloheptane-1,2-cis-diol (3c): yield 66%, white solid. Rf =
0.43 (pentane/Et2O, 1:1). m.p. 78–80 °C (CH2Cl2) (Lit.: 87–89 °C).[28] 1H
NMR (300 MHz, CDCl3): = 0.07 (d, J = 0.4 Hz, 9 H), 1.23–2.14 (m, 12 H),
3.75 (dd, J = 9.7, 1.8 Hz, 1 H) ppm. 13C NMR (75 MHz, CDCl3): = –2.66
(q), 20.63 (t), 23.75 (t), 28.51 (t), 31.63 (t), 34.46 (t), 70.46 (s), 76.19 (d)
ppm. IR (ATR): = 3438, 3357, 2930, 2856, 1447, 1329, 1244, 1047, 1013,
949, 832, 742, 707, 684 cm−1. ESI–MS (+25 V): m/z = 225.1 [M+Na]+.
1
cis Dihydroxylation of vinylsilanes 2a and 2e, representative
procedure: A mixture of alkene 2a (204 mg, 1.32 mmol), acetone (2.3 mL),
tBuOH (0.13 mL), water (0.23 mL), OsO4 (0.197 M in toluene, 0.05 mL,
0.01 mmol), and NMO·H2O (259 mg, 1.91 mmol) was stirred at 45 °C for
26 h. After cooling to room temperature, Et2O (5 mL) and water (5 mL)
were added, and the aqueous layer was extracted with Et2O (55 mL). The
combined organic layers were washed with aqueous 2 N HCl (20 mL),
aqueous sat. NaHCO3 (20 mL), brine (20 mL), dried over MgSO4 and
concentrated under reduced pressure. Flash chromatography of the
residue (ihexane/ethyl acetate, 3:1) afforded the cis diol 3a (196 mg, 79%)
as a white solid.
HRMS: calcd. for C10H22NaO2Si+ [M+Na]+ 225.1281; found 225.1283. H
NMR analysis matched previously reported data,[28] while 13C analysis
showed significant differences to the reported data.[21]
exo-2-Trimethylsilyl-norbornane-2,3-cis-diol (3d): yield 50%, white solid.
Rf = 0.38 (pentane/Et2O, 1:1). m.p. 43–45 °C (CH2Cl2) (Lit.: 48–50 °C).[28]
1H NMR (300 MHz, CDCl3): = 0.11 (s, 9 H), 0.98–1.05 (m, 1 H), 1.12 (dq,
J = 10.2, 1.5 Hz, 1 H), 1.24–1.32 (m, 1 H), 1.39 (tt, J = 12.8, 4.9 Hz, 1 H),
1.46–1.54 (m, 1 H), 1.92 (ddt, J = 10.3, 3.9, 2.0 Hz, 1 H), 2.12–2.16 (m,
1 H), 2.16–2.20 (m, 1 H), 3.56–3.72 (m, 1 H) ppm. 13C NMR (151 MHz,
CDCl3): = −2.51 (q), 23.91 (t), 24.77 (t), 33.72 (t), 44.69 (d), 46.86 (d),
73.79 (s), 76.74 (d) ppm. IR (ATR): = 3379, 3228, 2947, 2875, 1326,
1246, 1094, 1008, 975, 940, 881, 830, 747, 683 cm−1. ESI–MS (+10 V):
m/z = 218.2 [M+NH4]+, 401.3 [2M+H]+. C10H20O2Si (200.35): calcd. C 59.95,
H 10.06; found C 60.06, H 10.13. 13C NMR analysis showed significant
differences to the reported data.[21] The relative configuration of 3d was
determined using 2D NMR experiments.
1-(Trimethylsilyl)cyclohexane-1,2-cis-diol (3a): yield 79%, Rf = 0.48
(pentane/Et2O, 1:1). m.p. 85–86 °C (CH2Cl2) (Lit.: 85–88 °C).[16] 1H NMR
(300 MHz, CDCl3): = 0.07 (s, 9 H), 1.13–1.90 (m, 10 H), 3.60 (dd, J = 9.5,
5.6 Hz, 1 H) ppm. 13C NMR (75 MHz, CDCl3): = −3.03 (q), 19.08 (t),
24.21 (t), 29.73 (t), 32.10 (t), 68.79 (s), 73.46 (d) ppm. IR (ATR): = 3414,
3289, 2931, 2858, 1445, 1390, 1243, 1185, 1057, 996, 954, 922, 833, 817,
745, 686 cm−1. ESI–MS (+10 V): m/z = 171.0 [M−OH]+, 211.1 [M+Na]+.
Diol cleavage of 1,2-dihydroxysilanes 3a-c and 3e, representative
procedure: A mixture of cis diol 3a (43 mg, 0.28 mmol), NaIO4 (97 mg,
0.54 mmol), EtOH (18 mL), and water (4 mL) was stirred at room
temperature for 23 h. After addition of CH2Cl2 (20 mL) and water (20 mL),
the aqueous layer was extracted with CH2Cl2 (220 mL). The combined
organic layers were washed with water (50 mL) and brine (50 mL), dried
over MgSO4, and the solvents were removed under reduced pressure to
afford acylsilane 4a (41 mg, 96%).
1
C9H20O2Si (188.34): calcd. C 57.40, H 10.70; found C 57.25, H 10.82. H
NMR analysis matched previously reported data,[16] while 13C NMR
analysis showed significant differences to the reported data.[21]
1-Phenyl-1-(trimethylsilyl)ethane-1,2-diol (3e): The reaction was carried
out at room temperature. Yield 23%, colorless oil. Rf = 0.33 (pentane/Et2O,
1
1:1). H NMR (300 MHz, CDCl3): = 0.00 (s, 9 H), 1.99 (br. s, 1 H), 2.73
(br. s, 1 H), 3.93 (d, J = 11.7 Hz, 1 H), 4.15 (d, J = 11.5 Hz, 1 H), 7.15–
7.25 (m, 1 H), 7.26–7.40 (m, 4 H) ppm. 13C NMR (75 MHz, CDCl3): =
−3.82 (q), 67.44 (t), 73.89 (s), 125.03 (d), 125.89 (d), 128.43 (d), 143.43
(s) ppm. IR (ATR): = 3407, 2955, 2896, 1691, 1600, 1445, 1246, 1096,
1056, 1028, 830, 755, 698 cm−1. ESI–MS (+10 V): m/z = 193.1 [M−OH]+,
228.1 [M+NH4]+, 443.0 [2M+Na]+. HRMS: calcd. for C11H18NaO2Si+
[M+Na]+ 233.0968; found 233.09683.
1-(Trimethylsilyl)hexane-1,6-dione (4a): yield 96%, pale brown liquid. Rf =
0.65 (ihexane/EtOAc, 3:1). H NMR (300 MHz, CDCl3): = 0.20 (s, 9 H),
1.49–1.65 (m, 4 H), 2.44 (td, J = 6.9, 1.6 Hz, 2 H), 2.56–2.73 (m, 2 H), 9.76
(t, J =1.7 Hz, 1 H) ppm. 13C NMR (125 MHz, CDCl3): = −3.07 (q), 21.63
(t), 21.85 (t), 43.93 (t), 48.05 (t), 202.46 (d), 247.81 (s) ppm. IR (ATR): ν̃ =
2949, 2869, 2721, 2056, 1722, 1641, 1248, 840, 752 cm−1. GC–MS: m/z
(%) = 186 (4) [M]+, 171 (18), 143 (21), 129 (31), 115 (10), 101 (16), 75 (84),
73 (100), 45 (37). The spectra matched previously reported data.[18]
1
cis Dihydroxylation of vinylsilanes 2b-d, representative procedure: A
mixture of alkene 2b (561 mg, 4.00 mmol), tBuOH (8 mL), water (2.4 mL),
pyridine (0.32 mL, 4.0 mmol), OsO4 (0.197 M in toluene, 0.41 mL,
0.081 mmol), and NMO·H2O (755 mg, 5.58 mmol) was stirred at 100 °C
for 24 h. After cooling to room temperature, Na2S2O5 (10 g) in buffer pH 7
(10 mL) was added, and stirring was continued for 3 h. The aqueous layer
was extracted with Et2O (315 mL), all organic layers were combined and
washed with brine (40 mL), dried over MgSO4 and concentrated under
reduced pressure. The residue was purified by flash chromatography
(pentane/Et2O, 1:1) to afford the cis diol 3b (424 mg, 61%) as a white solid.
1-(Trimethylsilyl)pentane-1,5-dione (4b): yield 76%, colorless liquid. Rf =
0.36 (pentane/Et2O, 3:1). 1H NMR (300 MHz, CDCl3): = 0.18 (s, 9 H),
1.83 (quin, J = 7.0 Hz, 2 H), 2.42 (td, J = 7.1, 1.4 Hz, 2 H), 2.65 (t, J =
7.0 Hz, 2 H), 9.72 (t, J = 1.5 Hz, 1 H) ppm. 13C NMR (75 MHz, CDCl3): =
−3.21 (q), 14.62 (t), 43.20 (t), 47.05 (t), 202.18 (d), 247.33 (s) ppm. IR
(ATR): = 2957, 2899, 1719, 1640, 1249, 838, 752 cm−1. ESI–MS (+10 V):
m/z = 173.2 [M+H]+. The spectra matched previously reported data.[18]
1-(Trimethylsilyl)heptane-1,7-dione (4c): yield 98%, colorless liquid. Rf =
0.48 (pentane/Et2O, 3:1). 1H NMR (300 MHz, CDCl3): = 0.19 (s, 9 H),
1.22–1.35 (m, 2 H), 1.46–1.70 (m, 4 H), 2.43 (td, J = 7.3, 1.8 Hz, 2 H), 2.60
(t, J = 7.2 Hz, 2 H), 9.76 (t, J = 1.7 Hz, 1 H) ppm. 13C NMR (75 MHz,
CDCl3): = −3.10 (q), 21.81 (t), 21.99 (t), 28.87 (t), 43.77 (t), 48.13 (t),
202.64 (d), 248.19 (s) ppm. IR (ATR): = 2937, 2858, 2718, 1722, 1641,
1-(Trimethylsilyl)cyclopentane-1,2-cis-diol (3b): yield 61%, white solid.
Rf = 0.26 (pentane/Et2O, 1:1). m.p. 61–62 °C (CH2Cl2) (Lit.: 58–60 °C).[28]
1H NMR (300 MHz, CDCl3): = 0.05 (s, 9 H), 1.37–1.54 (m, 1 H), 1.60–
1.78 (m, 3 H), 1.78–1.96 (m, 2 H), 2.17 (br. s, 2 H), 4.01 (t, J = 6.9 Hz, 1 H)
ppm. 13C NMR (75 MHz, CDCl3): = −3.89 (q), 20.58 (t), 32.57 (t), 34.57
(t), 73.94 (s), 76.62 (d) ppm. IR (ATR): = 3444, 3309, 2961, 2932, 1454,
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