96 JOURNAL OF CHEMICAL RESEARCH 2011
Scheme 3
Celite cake was washed with acetone (3 × 15 mL). The filtrates were
Experimental
combined and evaporation of the solvent gave diols, which were
dissolved in pyridine (10 mL). To the magnetically stirred solution
was added Ac2O (10 mL). The reaction mixture was stirred at room
temperature for 12 h. The mixture was cooled to 0 °C and 4 N HCl
solution (80 mL) was added and extracted with ether (3x50 mL).
The combined organic extracts were washed with NaHCO3 solution
(10 mL) and water (45 mL) and then dried over Na2SO4. After the
evaporation of the solvent, gave anti–anti-3,4:8,9-tetraacetoxy-11-
oxa-tricyclo[4.4.1.01,6]undecane 16a and anti–syn-3,4:8,9-tetraace-
toxy-11-oxatricyclo[4.4.1.01,6] undecane 16b (1.76 g, 68 % from 14).
Crystallisation of the mixture (1.76 g) from ethyl acetate permitted
their separation (16a:1.20 g, 16b: 0.56 g).
16a: Colourless oily; Found: C, 56.17; H, 6.78. C18H24O9 requires:
C, 56.24; H, 6.29 %; IR (CHCI3, cm−1): 3698, 2936, 1736, 1437, 1371,
1247, 1163, 1046, 734, 608; 1H NMR (400 MHz CDCl3 ppm) δ 4.92
(m, 4H, –CH-O), 2.23 (dd, A part of AB system, J = 15.5, 6.8 Hz, 4H,
one of –CH2), 1.99 (dd, B part of AB system, J = 15.5, 7.3 Hz, 4H, one
of –CH2), 1.98 (s, 12H, –CH3); 13C NMR (100 MHz CDCl3 ppm)
δ 170.6 (4x –C=O), 67.6 (4x -C-O), 58.3 (2x bridgehead-epoxy-C),
32.7 (4x –CH2), 21.2 (4x –CH3).
Melting points were determined on a Büchi 539 capillary melting
apparatus and are uncorrected. IR spectra were obtained from KBr
or film on a Mattson 1000 FT-IR spectrophotometer. The 1H and 13
C
NMR spectra were recorded on 400 (100) MHz Varian spectrometer
and are reported in δ units with SiMe4 as internal standard. TLC was
performed on E. Merck Silica Gel 60 F254 plate (0.2 mm). All column
chromatography was performed on silica gel (60 mesh, Merck).
Elemental analyses were carried out on a Carlo Erba 1108 model
CHNS-O analyser.
1,4,5,8-Tetrahydro-naphthalene (13): Prepared from Birch reduc-
tion of naphthalene in 84 % yield as described in the literature.24,25
11-Oxa-tricyclo[4.4.1.01,6]undeca-3,8-diene (14): A solution of
m-chloroperbenzoic acid (mCPBA) (5.32 g, 21.63 mmol, 70% purity)
in dichloromethane (50 mL) was added dropwise to a solution of
1,4,5,8-tetrahydro-naphthalene 13 (2.38 g, 18.03 mmol) in dichloro-
methane (20 mL), the internal temperature being kept about –10 °C by
the ice-salt cooling. The reaction was stirred at the same temperature
for 5 h and was then quenched with a saturated solution of sodium
hydrogen carbonate. The product was extracted with dichloromethane
(3x50 mL); the combined extracts were washed with saturated sodium
hydrogen carbonate solution and brine, and dried with anhydrous
sodium sulfate. Removal of the solvent afforded the crude epoxide
product. The usual chromatographic separation of the crude mixture
with 30% ethyl acetate/hexane yielded successively the 11-oxa-tri-
cyclo[4.4.1.01,6]undeca-3,8-diene 14 (2.16 g) in 81% overall yield.
White crystals, m.p. 59–61 °C (from ethyl acetate) (Lit21: m.p. 60–
16b: White crystals, m.p. 160–162°C (from ethyl acetate); Found:
C, 56.05; H, 6.71. C18H24O9 requires: C, 56.24; H, 6.29 %; IR (CHCI3,
cm−1): 3697, 2940, 1736, 1444, 1370, 1243, 1162, 1103, 1040, 915,
1
739, 629; H NMR (400 MHz CDCl3 ppm) δ 4.99 (m, 4H, –CH-O),
2.33 (dd, A part of AB system, J = 15.4, 7.0 Hz, 2H, one of –CH2),
2.27 (dd, B part of AB system, J = 15.4, 5.8 Hz, 2H, one of –CH2),
2.03 (dd, A part of AB system, J = 15.4, 6.2 Hz, 2H, one of –CH2),
1.98 (dd, B part of AB system, J = 15.4, 6.2 Hz, 2H, one of –CH2),
2.02 (s, 6H, –CH3), 2.01 (s, 6H, –CH3); 13C NMR (100 MHz CDCl3
ppm) δ 170.8 (2x –C=O), 170.4 (2x –C=O), 67.7 (2x –C-O), 67.6
(2x –C-O), 59.6 (2x bridgehead-epoxy-C), 33.3 (2x –CH2), 32.6
(2x –CH2), 21.3 (4x –CH3).
1
62 °C); H NMR (400 MHz CDCl3 ppm) δ 5.46 (m, 4H, –CH=CH),
2.51 (dd, A part of AB system, J = 16.7, 2.8 Hz, 4H, one of –CH2),
2.36 (bd, B part of AB system, J = 16.7 Hz, 4H, one of –CH2); 13C
NMR (100 MHz CDCl3 ppm) δ 122.8 (2x –CH=CH), 60.5 (2x bridge-
head-epoxy-C), 31.0 (4x –CH2).
Anti–anti- and anti–syn-3,4:8,9-tetraacetoxy-11-oxa-tricyclo[4.4.1.01,6]
undecanes (16a and 16b): A 100 mL two-necked, round-bottomed
flask, equipped with a magnetic stirrer and a nitrogen inlet, was
charged with 1.75 g (14.8 mmol) of NMO, water (2 mL) and acetone
solvent (20 mL). To this solution were added a catalytic amount of
OsO4 (ca 10 mg, 0.08 mmol) and 1.0 g (6.76 mmol) of 11-oxa-tricyclo
[4.4.1.01,6]undeca-3,8-diene 14. The resulting mixture was stirred
vigorously under nitrogen at 0 °C. During the overnight stirring, the
reaction mixture became homogeneous. After stirring for 18 h, sodium
bisulfite (150 mg) and 3 g of Florisil sluried in 2 mL of water were
added, the slurry was stirred for 1 h, and the mixture was filtered
through a short pad 2 g of Celite in a 60 mL sintered glass funnel. The
Received 15 October 2010; accepted 1 December 2010
Paper 1000399 doi: 10.3184/174751911X12964930076566
Published online: 10 February 2011
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