=
1.14 (m, 1H), 0.98 (d, J = 6.5 Hz, 3H, CHMe2), 0.45 (d, J = 6.7 Hz,
3H, CHMe2);13C NMR (126 MHz, C6D6) d 143.9, 139.5, 130.0,
127.9, 85.4, 68.2, 52.3, 51.3, 32.6, 32.1, 30.3, 29.1, 27.2, 23.9, 22.1,
21.5, 21.1, 18.7, 18.5, 17.3; IR (thin film) 2947, 2859, 1475, 1319,
1115 cm-1; HRMS (ESI) m/z calc. for C26H43NaNO4SSi (M +
Na)+ 516.2580, found 516.2587.
2.61 (m, 4H, CH2CH2Ph and CMe CHCH2CH), 2.17 (m, 1H,
CH2CH2Ph), 1.90 (m, 1H, CH2CH2Ph), 1.69 (dd, J = 1.6, 0.8 Hz,
=
3H, CHCMe CH), 1.20 (s, 9H, Me3C), 1.11 (s, 9H, Me3C), 1.05
(d, J = 6.3 Hz, 6H, OCHMe2);13C NMR (126 MHz, C6D6) d
171.1, 149.7, 142.7, 129.2, 129.1, 126.6, 124.9, 78.9, 75.1, 68.3,
37.9, 34.2, 33.2, 29.3, 29.1, 29.0, 28.7, 22.1, 21.8, 19.9; IR (thin
film) 3027, 2969, 2935, 1755, 1729, 1105 cm-1; HRMS (CI) m/z
calc. for C26H42NaO4Si (M + Na)+ 469.2750, found 469.2753.
Diol 9. To a cooled (0 ◦C) solution of anti-Bredt olefin 5
(0.0480 g, 0.134 mmol) in acetone–H2O (10 : 1, 1.3 mL) was
added N-methylmorpholine-N-oxide (0.047 g, 0.40 mmol) and a
solution of osmium tetroxide in tert-butanol (0.084 mL, 2.5 wt%,
0.0067 mmol). The reaction mixture was allowed to warm to ambi-
ent temperature over 10 min before addition of saturated Na2S2O3
solution (2 mL). After stirring for 20 min, the layers were separated
and the aqueous layer was extracted with AcOEt (3 ¥ 3 mL). The
combined organic layers were washed with brine (10 mL), dried
Acknowledgements
This research was supported by the National Institute of Gen-
eral Medical Sciences of the National Institutes of Health
(GM-54909). K. A. W. thanks Amgen and Lilly for awards to sup-
port research. We thank Dr P. Dennison (UCI) for the assistance
with NMR spectroscopy, Dr J. W. Ziller (UCI) for X-ray crystal-
lography, and Dr J. Greaves and Ms. S. Sorooshian (UCI) for mass
spectrometry. A Fonds Que´be´cois de la Recherche sur la Nature
et les Technologies fellowship to M. P. is also acknowledged.
1
over NaSO4, and concentrated in vacuo. H NMR spectroscopic
analysis of the unpurified product indicated formation of 9 as a sin-
gle diastereomer. The resulting oil was purified by flash chromatog-
raphy (30 : 70 EtOAc–hexanes) to afford 9 as a white solid (0.048 g,
91%): mp = 144 ◦C; 1H NMR (400 MHz, CDCl3) d 7.47 (d, J =
7.6 Hz, 2H, Ph), 7.39 (t, J = 7.6 Hz, 2H, Ph), 7.29 (t, J = 7.3 Hz,
1H, Ph), 5.54 (s, 1H, OCHPh), 4.35 (s, 1H, HOCCH), 4.32 (d, J =
12.7 Hz, 1H, SiOCH2), 3.77 (d, J = 12.7 Hz, 1H, SiOCH2), 2.52
(br s, 1H, OH), 2.35 (m, 1H), 1.76 (m, 2H), 1.59 (m, 1H), 1.44 (m,
1H), 1.31 (m, 2H), 1.21 (s, 9H, Me3C), 1.16 (s, 9H, Me3C), 1.08 (m,
1H);13C NMR (101 MHz, C6D6) d 143.1, 128.2, 126.9, 125.5, 78.4,
75.8, 74.3, 70.6, 49.1, 29.3, 28.8, 27.9, 22.0, 21.1, 18.7, 16.9; IR (thin
film) 3412, 2935, 2860, 1475, 1124 cm-1; HRMS (ESI) m/z calc. for
C22H36NaO4Si (M + Na)+ 415.2281, found 415.2285. Anal. Calc.
for C22H36O4Si: C, 67.30; H, 9.24. Found: C, 67.33; H, 9.43%.
Notes and references
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Oxasilacyclohexene 11b. The representative procedure for
insertion of silylenes into vinyl epoxides was followed using vinyl
epoxide 10 (0.011 g, 0.15 mmol), silacyclopropane 2 (0.044 g,
0.196 mmol) and AgOTs (0.0008 g, 0.003 mmol) in benzene–THF
(1 : 1, 1.0 mL). The reaction mixture was concentrated in vacuo
and the resulting residue was purified by flash chromatography
(hexanes 100%) to afford oxasilacyclohexene 11b (0.0049 g, 15%)
as a clear volatile oil: 1H NMR (400 MHz, C6D6) d 5.81 (m, 1H,
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´
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=
=
OCH2CH CH), 5.38 (d, J = 10.4 Hz, 1H, OCH2CH CH), 4.36
124, 6524–6525.
(s, 2H, OCH2), 1.13 (m, 2H, SiCH2), 1.05 (s, 18H, 2 ¥ Me3C); 13
C
13 T. B. Clark and K. A. Woerpel, J. Am. Chem. Soc., 2004, 126, 9522–
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NMR (126 MHz, C6D6) d 129.6, 124.5, 64.3, 27.6, 21.1, 5.4; 29Si
NMR (99.3 MHz, C6D6) d 6.2; IR (thin film) 3024, 2931, 2858,
1469, 1178, 825 cm-1; HRMS (CI) m/z calc. for C12H25OSi (M +
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trans-Dioxasilacyclooctene 26. The representative procedure
for the formation of trans-dioxasilacycloctenes was followed using
vinyl epoxide 16 (0.070 g, 0.37 mmol), silacyclopropane 2 (0.13 g,
0.56 mmol), AgOTs (0.002 g, 0.007 mmol) and isopropyl 2-
oxoacetate45 solution in benzene (0.52 mL, 0.095 g, 0.82 mmol)
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Wilms, Justus Liebigs Ann. Chem., 1950, 567, 1; (b) A. C. Cope, R. A.
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20 For the preparation of functionalized trans-cyclooctenes, see: (a) C. B.
Reese and A. Shaw, J. Am. Chem. Soc., 1970, 92, 2566–2568; (b) D. C.
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1
in toluene–THF (1 : 1, 2.7 mL). H NMR spectroscopic analysis
of the unpurified product indicated formation of 26 as a single
diastereoisomer. The resulting oil was purified by flash chromatog-
raphy (3 : 97 Et3N–hexanes) to afford 26 as colorless oil (0.133 g,
1
80%): H NMR (400 MHz, C6D6) d 7.19 (m, 4H, Ph), 7.09 (m,
=
1H, Ph), 5.58 (ddq, J = 12.3, 3.6, 1.7 Hz, 1H, CH C), 5.03
(sept, J = 6.2 Hz, 1H, OCHMe2), 4.53 (dd, J = 9.8, 4.9 Hz, 1H,
=
SiOCH(CO2i-Pr)), 4.10 (dd, J = 8.3, 5.9 Hz, 1H, SiOCHCMe C),
9280 | Dalton Trans., 2010, 39, 9275–9281
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