New fragmentation of 1,3-dibromoadamantane

Full text of DOI:10.1023/A:1012403322523

Russian Journal of Organic Chemistry, Vol. 37, No. 7, 2001, pp. 1050 1051. Translated from Zhurnal Organicheskoi Khimii, Vol. 37, No. 7, 2001,
pp. 1096 1097.
Original Russian Text Copyright
2001 by Skomorokhov, Klimochkin.
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New Fragmentation of 1,3-Dibromoadamantane
M. Yu. Skomorokhov and Yu. N. Klimochkin
Samara State Technical University, Galaktionovskaya 141, Samara, 443010 Russia
e-mail: orgchem@sstu.samara.ru
Received May 5, 2000
It is known that tricyclic 1,3-dibromoadamantane
(I) can be converted into 7-methylenebicyclo[3.3.1]-
nonan-3-one [1]. We have found that in the presence
of a strong base in ethylene glycol at 200 C dibromo-
adamantane (I) gives rise to a mixture of 3-(2-hy-
droxyethoxy)-7-methylenebicyclo[3.3.1]non-2-ene (II)
and 3,3-ethylenedioxy-7-methylenebicyclo[3.3.1]-
nonane (III). The reaction is likely to involve inter-
mediate formation of adamantylcarbenium ion A
which undergoes isomerization according to Grob [2],
yielding cation B. The latter is stabilized through
formation of compounds II and III (Scheme 1). As
might be expected [3], vinyl ether II is converted into
1,3-dioxolane derivative III on distillation or during
chromatography on silica gel. We succeeded in isolat-
ing only 3-(2-acetoxyethoxy)-7-methylenebicyclo-
[3.3.1]non-2-ene (IV).
of ethylene glycol we added 70 g (0.238 mol) of
dibromoadamantane I. The mixture was refluxed for
3 h, poured into water, and extracted with chloroform.
The extract was washed with water, dried over anhy-
drous sodium sulfate, and evaporated. The residue
was dissolved in 100 ml of toluene, 22 ml (0.165 mol)
of triethylamine and 14 ml (0.137 mol) of acetic
anhydride were added, and the mixture was refluxed
for 1 h and washed with a 5% solution of sodium
carbonate and water. The solvent was distilled off,
and the residue was distilled under reduced pressure.
3,3-Ethylenedioxy-7-methylenebicyclo[3.3.1]-
nonane (III) (first fraction). Yield 5 g (11%), bp 99
100 C (1 mm), n2D0 1.5071. IR spectrum, , cm :
1
1
1660, 1110, 890. H NMR spectrum, , ppm: 1.25
2.35 m (12H), 3.77 m (4H, OCH2CH2O), 4.66 s (2H,
CH2). Mass spectrum, m/z (Irel, %): 194 [M]+ (17),
139 (100), 106 (41), 92 (33). Found, %: C 79.11;
H 9.40. C12H18O2. Calculated, %: C 79.19; H 9.34.
Ring opening in 1,3-dibromoadamantane. To
a solution of 25 g (1.09 mol) of sodium in 500 ml
Scheme 1.
1070-4280/01/3707-1050$25.00 2001 MAIK Nauka/Interperiodica

NEW FRAGMENTATION OF 1,3-DIBROMOADAMANTANE
1051
3-(2-Acetoxyethoxy)-7-methylenebicyclo[3.3.1]-
non-2-ene (IV) (second fraction). Yield 7.5 g (14%),
bp 135 136 C (1 mm), n2D0 1.5028. IR spectrum, ,
cm : 1750, 1660, 1050, 895. H NMR spectrum, ,
ppm: 1.6 2.5 m (10H), 1.98 s (3H, COCH3), 3.73 t
(2H, OCH2, J = 4.5 Hz), 4.17 t (2H, CH2OAc), 4.43 s
(1H, CH), 4.62 s (1H, CH), 4.46 d (1H, HC CO,
J = 6 Hz). Mass spectrum, m/z (Irel, %): 236 [M]+ (3),
87 (100), 43 (47). Found, %: C 71.10; H 8.47.
C14H20O3. Calculated, %: C 71.16; H 8.53.
4.46 d (1H, HC CO, J = 6 Hz). Mass spectrum, m/z
(Irel, %): 264 [M]+ (7), 149 (76), 107 (58), 43 (100).
Found, %: C 72.71; H 9.20. C16H24O3. Calculated, %:
C 72.69; H 9.15.
1
1
The IR spectra were recorded on an IKS-22 spec-
1
trometer from samples prepared as thin films. The H
NMR spectra were obtained on a Bruker AC-200
instrument (200 MHz) in CDCl3 with HMDS as
internal reference. The mass spectra (70 eV) were run
on a Finnigan MAN JNCOS50 spectrometer.
In a similar way, 1,3-dibromoadamantane (I) re-
acted with 1,4-butanediol in the presence of sodium
alkoxide. Acetylation followed by vacuum distillation
gave 10.1 g (16%) of 3-(4-acetoxybutoxy)-7-methyl-
enebicyclo[3.3.1]non-2-ene, bp 148 149 C (1 mm),
REFERENCES
1. Stetter, H. and Tacke, P., Chem. Ber., 1963, vol. 96,
no. 3, p. 694.
n2D0 1.4933. IR spectrum, , cm : 1750, 1660, 1050,
1
2. Grob, C.A., Angew. Chem., 1976, vol. 88, no. 19,
1
pp. 621 656.
895. H NMR spectrum, , ppm: 1.6 2.5 m (14H),
1.98 s (3H, COCH3), 3.61 m (2H, OCH2), 4.05 m
(2H, CH2OAc), 4.46 s (1H, CH), 4.67 s (1H, CH),
3. Shostakovskii, M.F., Prostye vinilovye efiry (Vinyl
Ethers), Moscow: Akad. Nauk SSSR, 1952.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 37 No. 7 2001