CONVENIENT PREPARATIVE SYNTHESIS OF PENTACYCLO[5.3.0.02,5.03,9.04,8]DECANE
1635
decane (basketane) that under the identical conditions
rearranged into snoutane [12]. This procedure sig-
nificantly simplified the purification of C2-bishomo-
cubane VII from unsaturated impurities formed in the
Wolf-Kishner reaction.
105 (70.9), 91 (71.2) [C7H7], 77 (100) [C6H5], 66 (43.6)
[C5H6], 65 (47.3) [C5H5]. Found, %: C 69.86; H 6.82.
C12H14O3. Calculated, %: C 69.88; H 6.84.
6-Chloropentacyclo[5.3.0.02,5.03,9.04,8]-decan-10-
one ethyleneketal (IV). In 100 ml of tetrachloromethane
was dissolved 8.85 g (0.043 mol) of oxyketal III, 12.59 g
(0.048 mol) of triphenylphosphine, and the mixture was
boiled at stirring for 4 h. Then 3 ml of MeOH was added,
and the boiling was continued for 1 h. On cooling the
separated precipitate of triphenylphosphine oxide was
filtered off. The tetrachloromethane was evaporated in
a vacuum, the residue was extracted with 100 ml of ether.
The insoluble residue of triphenylphosphine oxide was
filtered off, to the mother loquor was added 4–5 g of finely
ground lithium iodide monohydrate, and the stirring at room
temperature continued for 1.5–2 h. The precipitate formed
was filtered in a vacuum through a layer of finely dispersed
silica gel. The solvent was evaporated in a vacuum. Yield
8.82 g (92%), mp 72.5–74°C (from methanol). 1H NMR
spectrum, δ, ppm: 2.23 m (1H, CH), 2.51 m (1H, CH),
2.88–2.98 m (6H, CH), 3.85–4.05 m (4H, CH2), 4.21 s
(1H, CHCl). 13C NMR spectrum, δ, ppm, of anti-epimer:
36.3 (C3), 38.9 (C4), 40.5 (C8), 40.8 (C2), 41.57 6 (C9),
47.4 (C5), 48.6 (C1), 52.0 (C7), 65.1 (C11), 65.2 (C12), 67.8
(C6), 123.6 (C10); of syn-epimer: 36.27 (C3), 37.7 (C4),
39.7 (C8), 40.9 (C2), 44.1 (C9), 46.4 (C5), 49.6 (C1), 51.5
(C7), 64.8 (C11), 64.8 (C12), 67.0 (C6), 122.9 (C10). Mass
spectrum m/z (Irel, %): 226 (4.2) [M(37Cl)]+ 224 (11.2)
[M(35Cl)]+, 189 (100) [M – Cl], 117 (69.2), 115 (71.6), 91
(30.2) [C7H7], 73 (38.4) [C3H5O2], 65 (16.3) [C5H5].
Found, %: C 64.19; H 5.87. C12H13ClO2. Calculated, %:
C 64.15; H 5.83.
Thus we developed a convenient synthesis of C2-
bishomocubane consisting in a successive reduction of
framework keto groups with an overall preparative yield
no less than 75–80%. Besides we developed preparative
procedures for isolating intermediate compounds that
might be employed for preparation of enantiomeric
derivatives of C2-bishomocubane.
EXPERIMENTAL
1H and 13C NMR spectra were registered on a spec-
trometer Bruker DPX-400 at operating frequencies
400.13 and 100.61 MHz respectively from solutions in
CDCl3, internal reference TMS. GC-MS measurements
were performed on an instrument Hewlett-Packard
5971A(Electron impact, 70 eV, mass-selective detector),
chromatograph HP 5890, column HP-5 (5% phenyl-
methylsilicone), vaporizer temperature 250°C, oven
temperature 60–250°C, heating rate 20 deg/min. GLC
was carried out on a capillary chromatograph Shimadzu
GC-14B equipped with a flame-ionization detector,
column Optima-1, vaporizer temperature 280°C, oven
temperature 70–280°C, heating rate 20 deg/min.
6-Hydroxypentacyclo-[5.3.0.02,5.03,9.04,8]decan-
10-one ethyleneketal (III). To a dispersion of 2.2 g
of lithium aluminum hydride in 70 ml of anhydrous ether
was added dropwise at stirring a solution of 12 g
(0.059 mol) of ketoketal I in 200 ml of anhydrous ether.
The reaction mixture was boiled at vigorous stirring for
12 h, then at cooling with ice water to it was added
dropwise in succession 2.2 ml of water, 2.2 ml of 15%
solution of NaOH, and 6.6 ml of water. The separated
precipitate was filtered off on a glass frit and thoroughly
washed several times with ether. The ether solution was
dried with Na2SO4, the solvent was distilled off. Yield
11.04 g (91%), mp 99–100°C (from a mixture hexane–
Pentacyclo[5.3.0.02,5.03,9.04,8]-decan-6-one ethyl-
eneketal (V). To a solution of 6.25 g (0.031 mol) of com-
pound IV in 200 ml of anhydrous THF and 10 ml of t-BuOH
was added 1.6 g (0.23 mol) of fine lithium wire. The
mixture obtained was boiled for 2 h, 5 ml more of t-BuOH
was added, and the mixture was boiled for another 2–
3 h. The excess lithium was destroyed after the reaction
by adding water at cooling. The reaction product was
extracted from the water solution into dichloromethane,
the extract was dried with Na2SO4, the solvent was
distilled off in a vacuum. Yield 5.1 g (99%), bp 122–126°C
1
THF). H NMR spectrum, δ, ppm: 1.93 s (1H in OH),
2.52 m (1H, CH), 2.70–2.88 m (6H, CH), 3.08 m (1H,
CH), 3.88–4.02 m (4H, CH2), 4.10 s (1H, CH). 13C NMR
spectrum of syn-epimer, δ, ppm: 36.8 (C3), 36.9 (C4),
39.1 (C2), 40.6 (C8), 43.4 (C9), 45.7 (C5), 48.8 (C7), 49.9
(C1), 64.8 (C11), 65.1 (C12), 82.9 (C6), 124.0 (C10). Mass
spectrum, m/z (Irel, %): 206 (24) [M]+, 188 (48) [M –
H2O], 187 (67.3), 138 (61.8), 115 (63.6) [M – C7H7],
1
(14 mm Hg). H NMR spectrum, δ, ppm: 1.35 d and
1.61 d (AC system, 2H, CH2, JAC 12 Hz), 2.15 m (1H,
CH), 2.41 m (1H, CH), 2.66–2.93 m (6H, CH), 3.85–
4.05 m (4H, CH2). 13C NMR spectrum, δ, ppm: 37.0 (C4),
39.8 (C10), 40.1 (C3), 41.2 (C9), 41.4 (C2), 41.8 (C8), 42.8
(C5), 45.2 (C1), 51.0 (C7), 64.7 (C11), 65.0 (C12), 123.7
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 45 No. 11 2009