1378
MAMEDOV et al.
The IR spectra of V and VI contain stretching vibra-
(2R)-(+)-Bicyclo[2.2.2]oct-5-ene-5-carboxylic acid
V was prepared by base hydrolysis of IV. Compound
IV (5.8 g) was refluxed in 30 ml of a 5% solution
of KOH in methanol for 2 h. After removing the sol-
vent, the residue was dissolved in 30 ml of water,
and the reaction products were extracted with ether.
The aqueous layer was treated with dilute HCl, and
the ether extraction was repeated. The extract was
washed with water and dried over MgSO4. After re-
moving the solvent, compound V was obtained in
a yield of 2.77 g, mp 56 57 C (from petroleum ether),
[ ]2D0 = +29.9 (c 0.2, EtOH).
tion bands of C=O at 1730 1735, C O at 1110, C=C
1
at 1625 1630, and =C H at 3030 cm . The spectrum
of VII contains stretching vibration bands of O H at
1
3350, C=C at 1625, and =C H at 3030 cm .
1
In the H NMR spectra of IV, V, and VII, the ole-
finic protons appear as a multiplet at 6.25 6.27 ppm
(J 5.62 Hz); the OH proton in VII gives a singlet
at 4.0 ppm, and the COOH proton in V, a singlet at
12.0 ppm.
The optical yield of V and VII (%) was determined
by comparing their specific rotations with those of
the enantiomerically pure samples of the same com-
pounds [3]. THe correlation of the optical rotation
sign for the compounds described in [3] allowed us to
assign the 2R configuration to dextrorotatory isomers
of V and VII.
(2R)-(+)-2-Hydroxymethylbicyclo[2.2.2]oct-5-ene
VII. A solution of 5.8 g of adduct IV in 30 ml of ab-
solute ether was added dropwise to a suspension of
4 g of LiAlH4 in 200 ml of absolute ether. Excess
LiAlH4 was decomposed with water. Cooled dilute
HCl was added to the resulting mixture, and the ether
layer was separated, washed with 5% NaHCO3 and
water to neutral reaction, and dried over MgSO4.
The solvent was removed, and the residue was vacu-
um-distilled. Yield of VII 2.2 g (88%), bp 75 76 C
(10 mm Hg), [ ]2D0 = +4.6 (c 0.11, EtOH).
EXPERIMENTAL
The IR spectra were measured on a UR-20 spec-
1
trophotometer in the range 4000 400 cm from thin
1
films or KBr pellets. The H NMR spectra were re-
corded on a Tesla BS-487C spectrometer (80 MHz,
CCl4, internal reference HMDS). The optical rotation
was measured with a Perkin Elmer-141 polarimeter.
Chromatographic analysis of the products and deter-
mination of their purity were done on an LKhM-8MD
chromatograph equipped with a thermal conductivity
detector (300 0.3-cm column, 7% polypropylene
sebacate on Poravina, carrier gas He, flow rate
CONCLUSIONS
(1) Asymmetric diene synthesis from ( )-menthyl
acrylate and cyclohexa-1,3-diene in the presence of
achiral catalysts TiCl4, AlCl3, BBr3, AlCl3 OEt2, and
BBr3 OEt2 yields chiral bicyclo[2.2.2]octenes with
the (2R)-(+) configuration.
1
40 ml min , column temperature 155 C, vaporizer
temperature 250 C).
(2) As temperature is lowered, the optical yield of
bicyclo[2.2.2]octenes increases and reaches 87% at
0 C; as temperature is elevated, the total yield in-
creases, and the endo selectivity decreases.
( )-Menthyl acrylate III was prepared as described
in [4]; [ ]2D0
=
76 (c 4.4, EtOH).
(3) The nature of the solvent and catalyst affects
the optical and chemical yields of the products insig-
nificantly. As the amount of the catalyst increases,
the optical yield varies insignificantly, and the total
yield grows.
( )-Menthyl bicyclo[2.2.2]oct-5-ene-2-carboxylate
IV. A solution of 1.25 g (0.005 mol) of BBr3 in 10 ml
of CH2Cl2 was added at 10 C to a solution of 4.2 g
(0.02 mol) of ( )-menthyl acrylate III in 15 ml of
CH2Cl2. Then the temperature was increased to 0 C,
and a solution of 1.6 g (0.02 mol) of cyclohexa-1,3-
diene II in 10 ml of CH2Cl2 was added dropwise.
The mixture was stirred for 3 h at 0 C, after which it
was treated successively with dilute HCl and 5%
NaHCO3, washed with distilled water, and dried over
MgSO4. The solvent was removed, and the residue was
vacuum-distilled. Yield of adduct IV 1.914 g (33%),
bp 160 162 C (2 mm Hg), [ ]2D0 (c 0.5, EtOH).
REFERENCES
1. Potapov, V.M., Stereokhimiya (Stereochemistry), Mos-
cow: Khimiya, 1988.
2. Chinchilla, R., Falvello, I.R., Gallindo, N., et al.,
Tetrahedron. Asymmetry, 1999, vol. 10, no. 6,
pp. 821 825.
3. Cervinka, O. and Kriz, O., Coll. Czech. Chem.
Commun., 1968, vol. 33, pp. 2342 2345.
The other experiments on synthesis of IV were
performed similarly (for specific conditions and re-
sults, see Table 1).
4. Williamson, K.L. and Li Hsu, Y., J. Am. Chem. Soc.,
1970, vol. 92, no. 16, pp. 7386 7389.
RUSSIAN JOURNAL OF APPLIED CHEMISTRY Vol. 80 No. 8 2007