References and Notes
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General Procedure
To
the solution of epoxide (5 mmol) in CH2Cl2 (8
mL) was added active MgX2˙THF (2.0 equiv, M = 1.78
mol/L) at r.t. The reaction was stirred at the same temperature
for 1 min and then quenched with sat. aq NH4Cl. The solvent
was removed under vacuum. and the residue was extracted with EtOAc.
The combined organic layer was washed with H2O and brine,
dried over anhyd Na2SO4, and concentrated
under reduced pressure. Purification of the residue was by chromatography
on SiO2 to give the product.
<A NAME="RW19408ST-9">9</A>
Spectral Data of
Compounds 1a-c, 2a,b, 3c, 7a, 7a′, 7b, 7b′ matched
in all respects with reported data.
Analytical
Data of Compounds 3-6
Compound 3a: ¹H NMR (400 MHz,
CDCl3): δ = 3.78
(m, 1 H), 3.53 (dd, J = 12.0,
4.0 Hz, 1 H), 3.43-3.36 (m, 3 H), 2.39 (br, 1 H), 1.92-1.82
(m, 2 H), 1.62-1.51 (m, 4 H). ¹³C
NMR (100 MHz, CDCl3): δ = 70.8,
40.3, 34.1, 33.6, 32.4, 24.3. IR (neat): 3393, 2941, 2864, 1432,
1259, 1050, 666, 561 cm-¹. HRMS (EI): m/z [M - H]+ calcd
for C6H12Br2O: 258.9234; found:
258.9156.
Compound 3b: ¹H
NMR (400 MHz, CDCl3): δ = 3.56-3.48 (m,
1 H), 3.42-3.35 (m, 3 H), 3.22 (t, J = 8.0
Hz, 1 H), 2.34 (br, 1 H), 1.90-1.84 (m, 2 H), 1.60-1.48
(m, 4 H). ¹³C NMR (100 MHz, CDCl3): δ = 70.7,
35.6, 33.7, 32.4, 24.3, 16.4.
Compound 4a: ¹H
NMR (400 MHz, CDCl3): δ = 4.74
(dd, J = 28.0,
8.0 Hz, 2 H), 3.98-3.92 (m, 1 H), 3.75 (dd, J = 12.0,
4.0 Hz, 1 H), 3.67 (dd, J = 12.0,
4.0 Hz, 1 H), 3.57 (dd, J = 12.0,
8.0 Hz, 1 H), 3.41 (s, 3 H), 2.75 (br, 1 H), 2.63 (d, J = 4.0 Hz,
2 H), 0.14 (s, 9 H). ¹³C NMR (100 MHz, CDCl3): δ = 102.6,
96.6, 87.4, 76.7, 72.0, 56.0, 36.4, 22.4, -0.0(4). IR (neat):
3437, 2958, 2899, 2177, 1420, 1250, 699, 646 cm-¹.
HRMS (EI): m/z [M - H]+ calcd
for C11H21BrO3Si: 307.0443; found:
307.0349.
Compound 4b: ¹H
NMR (400 MHz, CDCl3): δ = 4.77-4.68 (m,
2 H), 3.75-3.66 (m, 2 H), 3.49-3.45 (m, 1 H),
3.40 (d, J = 8.0
Hz, 3 H), 3.35-3.31 (m, 1 H), 2.75 (br, 1 H), 2.61 (d, J = 8.0 Hz,
2 H), 0.12 (d, J = 8.0
Hz, 9 H). ¹³C NMR (100 MHz, CDCl3): δ = 102.6,
96.7, 87.4, 78.4, 72.2, 56.1, 22.4, 11.0, -0.0(0).
Compound 5a: ¹H NMR (400 MHz,
CDCl3): δ = 3.79-3.72 (m,
2 H), 3.59 (dd, J = 12.0,
4.0 Hz, 1 H), 3.51-3.43 (m, 2 H), 3.35 (dd, J = 12.0,
8.0 Hz, 1 H), 2.76 (br, 2 H), 1.55-1.43 (m, 6 H), 1.40-1.30
(m, 4 H). ¹³C NMR (100 MHz, CDCl3): δ = 71.3,
71.0, 50.4, 40.4, 34.9, 34.0, 29.3, 29.2, 25.4, 25.3.
Compound 5b: ¹H NMR (400 MHz,
CDCl3): δ = 3.78-3.73 (m,
1 H), 3.57 (dd, J = 8.0,
4.0 Hz, 1 H), 3.50-3.42 (m, 2 H), 3.32 (dd, J = 8.0, 4.0
Hz, 1 H), 3.21-3.17 (m, 1 H), 3.04 (br, 2 H), 1.55-1.39
(m, 6 H), 1.38-1.26 (m, 4 H). ¹³C
NMR (100 MHz, CDCl3): δ = 71.3,
70.8, 50.3, 36.4, 34.0, 29.2, 25.5, 25.4, 16.3.
Compound 6a: ¹H NMR (400 MHz,
CDCl3): δ = 3.85-3.79 (m,
2 H), 3.56 (dd, J = 12.0,
4.0 Hz, 1 H), 3.48-3.38 (m, 3 H), 2.14 (d, J = 4.0 Hz,
1 H), 1.61-1.50 (m, 4 H), 1.43-1.32 (m, 6 H),
0.91 (s, 9 H), 0.10 (d, J = 8.0
Hz, 6 H). ¹³C NMR (100 MHz, CDCl3): δ = 72.4,
71.0, 48.5, 40.6, 35.0, 34.8, 29.5, 25.8, 25.5, 24.7, 18.1, -4.5, -4.6.
IR (neat): 3393, 2931, 2857, 1463, 1255, 1099, 837, 777 cm-¹.
Compound 6b: ¹H NMR (400 MHz,
CDCl3): δ = 3.85-3.80 (m,
1 H), 3.56-3.48 (m, 1 H), 3.46-3.38 (m, 3 H),
3.25 (dd, J = 12.0,
8.0 Hz, 1 H), 2.03 (d, J = 8.0
Hz, 1 H), 1.66-1.53 (m, 4 H), 1.46-1.31 (m, 6
H), 0.91 (s, 9 H), 0.10 (d, J = 4.0 Hz,
6 H). ¹³C NMR (100 MHz, CDCl3): δ = 72.4,
70.9, 48.5, 36.5, 34.8, 29.5, 25.8, 25.6, 24.7, 18.1, 16.6, -4.4, -4.6.
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Eisch JJ.
Liu ZR.
Zheng GX.
J.
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1992,
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