Synthesis and chiroptical properties of enantiopure tricyclo[4.3.0.03,8]nonane-4,5-dione (twistbrendanedione)

Article abstract of DOI:10.1016/S0957-4166(02)00157-X

The synthesis of chiral tricyclo[4.3.0.0^3,8]nonane-4,5-dione was accomplished starting from enantiomerically pure (+)-(1S,5S)-bicyclo[3.3.1]nonane-2,6-dione 1. Ring contraction of the latter with thallium(III) nitrate proceeded with high stereo

Full text of DOI:10.1016/S0957-4166(02)00157-X

TETRAHEDRON:
ASYMMETRY
Pergamon
Tetrahedron: Asymmetry 13 (2002) 633–638
Synthesis and chiroptical properties of enantiopure
3,8
tricyclo[4.3.0.0 ]nonane-4,5-dione (twistbrendanedione)
a,
a
a
a
b
Eugenius Butkus, * Albinas Z
Vladim ´ı r Setni cˇ ka, Petr Bou rˇ and Karel Volka
&
ilinskas, Sigitas Ston cˇ ius, Ri cˇ ardas Rozenbergas, Marie Urbanov a´ ,
c
c,d
c
a
Department of Organic Chemistry, Vilnius University, Naugarduko 24, 2006 Vilnius, Lithuania
b
Department of Physics and Measurement, Institute of Chemical Technology, Technick a´ 5, 16628 Praha 6, Czech Republic
c
Department of Analytical Chemistry, Institute of Chemical Technology, Technick a´ 5, 16628 Praha 6, Czech Republic
d
Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo n a´ m. 2,
16610 Praha 6, Czech Republic
Received 16 March 2002; accepted 21 March 2002
3,8
Abstract—The synthesis of chiral tricyclo[4.3.0.0 ]nonane-4,5-dione was accomplished starting from enantiomerically pure
+)-(1S,5S)-bicyclo[3.3.1]nonane-2,6-dione 1. Ring contraction of the latter with thallium(III) nitrate proceeded with high
(
stereoselectivity giving exclusively methyl (+)-(1S,4S)-(+)-exo,exo-bicyclo[2.2.1]heptan-2,5-dicarboxylate 2. Inversion of the
configuration of this diester to the required di-endo derivative was realized via the following reaction sequence. Bromination of
the corresponding acid dichloroanhydride and subsequent reduction with zinc in acetic acid gave a diastereoisomeric mixture of
esters, from which the endo,endo-ester 5 was isolated by column chromatography. Acyloin condensation of the latter with
trimethylchlorosilane in toluene led to intramolecular ring closure, and subsequent oxidation of the enol silyl ether 7 in situ gave
3,8
tricyclo[4.3.0.0 ]nonane-4,5-dione 8. The chiroptical properties of this cage molecule were studied by electronic and vibrational
circular dichroism spectroscopy. The (1R,3R,6R,8R) absolute configuration of the title structure was also unambiguously proved.
©
2002 Elsevier Science Ltd. All rights reserved.
1. Introduction
2. Results and discussion
Study of chiroptical phenomena in ketones gives insight
into modes of interaction between the carbonyl group
and perturbing substituents. Many examples of success-
ful applications of the octant rule used to account for
the Cotton effect (CE) observed in the electronic circu-
2
.1. Synthesis
Regarding the foregoing we considered that the synthe-
sis of the chiral cage a-diketone structure, tricyclo-
3,8
[4.3.0.0 ]nonane-4,5-dione
8
(twistbrendanedione)
1
lar dichroism spectra are found in the literature. A
would afford a suitable model for the study of chiropti-
cal properties of a-diketones. Although derivatives of
this cage molecule have been synthesized, it should be
noted that only the synthesis of the monocarbonyl
derivative has been reported. Thus, the synthesis of
the a-dicarbonyl derivative of twistbrendane was elabo-
rated based on transformation of (+)-(1S,5S)-bicyclo-
special case is chiral 1,2-diketones for which no clear
rule is available. Only a few examples of the circular
3
2
dichroism study in such systems are available and the
CE is difficult to predict since low energy n-p* transi-
tion above 350 nm is controlled by the both diketone
chirality alone and adjacent substituents. Thus, 1,2-
diketones with appropriate location of carbonyl groups
in the molecule are of interest for chiroptical studies.
3c
[
3.3.1]nonane-2,6-dione 1 (Scheme 1), which was
obtained by kinetic resolution of the corresponding
racemic diketone using baker’s yeast according to a
3,8
Herein, the synthesis of chiral tricyclo[4.3.0.0 ]nonane-
4
,5-dione (twistbrendanedione), an a-diketone struc-
4
procedure described in the literature. Oxidation of 1
mol of (+)-diketone 1 with 2 mol of thallium(III)nitrate
ture, was accomplished, and the chiroptical properties
of this structure were studied by electronic (ECD) and
vibrational circular dichroism (VCD) spectroscopy.
(
TTN) in methanol proceeded with oxidative
5
rearrangement and exclusively afforded methyl (+)-
exo,exo-bicyclo[2.2.1]heptan-2,5-dicarboxylate in
2
1
13
good yield (85%). Analysis of the H and C NMR
spectra of (+)-2 proved the structure of the ring con-
*
0
Corresponding author. E-mail: eugenijus.butkus@chf.vu.lt
957-4166/02/$ - see front matter © 2002 Elsevier Science Ltd. All rights reserved.
PII: S0957-4166(02)00157-X

6
34
E. Butkus et al. / Tetrahedron: Asymmetry 13 (2002) 633–638
H CO C
CO CH
3
HOOC
COOH
3
2
2
O
1
5
O
i)
1
4
ii)
(1S,5S)-1
(1S,4S)-2
(1S,4S)-3
iii)
H CO C
3
2
Br
H CO C
iv)
Br
CO CH
H CO C
CO CH
3
2
3
2
2
3
CO CH3
2
3
2
6
5
v)
4
1
vi)
6
O
O
(
H C) SiO
OSi(CH3)2
3
2
8
7
Scheme 1. Reagents: (i) Tl(NO ) , CH OH; (ii) H /H O; (iii) SOCl , Br ; (iv) Zn, AcOH; (v) (CH ) SiCl, Na; (vi) Br /CCl .
+
3
3
3
2
2
2
3 3
2
4
1
3
traction product. The spin–spin coupling constants
JH2endoH3endo and JH2endoH3exo are 9.0 and 5.5 Hz,
45.5 and 51.3 in the C NMR spectrum are strongly
indicative of this di-endo-structure. The signals were
assigned to C-3(6), C-1(4), C-7, C-2(5) and the CH3
group, respectively. These values were calculated by the
additivity scheme considering chemical shifts of bicyc-
lo[2.2.1]heptane and the corresponding methyl esters of
respective exo- and endo-bicyclo[2.2.1]heptane-2-car-
3
3
respectively, and correspond to the calculated values by
the Karplus equation, i.e. 10.8 and 6.1 Hz. Five carbon
atom signals at 33.5, 34.2, 40.2, 45.2 and 51.3 were
assigned to C-3(6), C-7, C-1(4), C-2(5) and the CH3
group, respectively. The high stereoselectivity of this
conversion is in accordance with earlier observations in
9
10
boxylic acids and also by using ACDLabs software.
6
the stereoselectivities of bicyclo[3.2.1]octan-2-one and
The enantiomerically pure endo,endo-diester (+)-
(1S,4S)-5 was used for synthesis of the target twistbren-
danedione. Acyloin condensation of the endo,endo-
diester 5 with trimethylchlorosilane in toluene led to
the intramolecular ring closure to give enol silyl ether 7.
Oxidation of the enol silyl ether in situ with bromine
gave (+)-tricyclo[4.3.0.0 ]nonane-4,5-dione 8. The
splitting of the carbonyl groups absorption at 1760 and
1743 cm is observed in the IR spectrum of 8. Three
groups of proton signals and five distinct carbon atoms
in the H NMR and in the C NMR spectra, respec-
7
other ring contraction reactions of bicyclic ketones,
and agree with the general reaction mechanism pro-
8
posed by McKillop.
The endo,endo-diester was required to give the target
tricyclic structure upon ring closure. An attempt to
obtain the requested diastereoisomer by epimerization
of 2 with sodium methoxide in methanol gave a mixture
consisting of initial exo,exo-2 and exo,endo-6
diastereoisomers in the ratio 85:15. Calculations by
semiempirical PM3 methods proved that the di-exo
diastereoisomer is thermodynamically more stable by
3,8
−
1
1
13
13
tively, are observed for 8. The C shifts at 36.4, 39.2,
41.1, 45.8 and 202.2 ppm correspond with the C2
symmetry of the tricyclic structure 8.
2.2 kcal/mol compared to di-endo diastereoisomer. The
successful inversion of configuration of diester (+)-2
involved a reaction of the latter with thionyl chloride,
subsequent addition of bromine and the esterification
with methanol to yield a mixture of diastereoisomeric
a-bromo methyl esters 4. Reduction of bromine with
zinc in acetic acid afforded a mixture of esters 5 and 6.
The predominance of the di-endo ester (+)-5 in the
mixture as shown by GC–MS analysis and the spin–
2.2. Chiroptical studies by ECD and VCD
In this work, the ECD and VCD spectroscopy was
applied to study chiroptical properties of the diketone
(+)-8. A complex ECD spectrum with a positive band
below 235 nm, a negative band centered at 280 nm, and
the positive band at 420 nm was observed for 8 (Fig. 1).
The sign of the CE in the molecule (+)-8 is determined
by two carbonyl chromophores in this chiral structure.
The contributions from two chromophores are assumed
1
spin coupling constants in the H NMR spectrum. The
latter diastereoisomer (+)-5 was isolated by the column
chromatography. The chemical shifts at 26.8, 40.3, 41.0,

E. Butkus et al. / Tetrahedron: Asymmetry 13 (2002) 633–638
635
experimental spectra has been used for the determina-
13
tion of absolute configuration of small as well as
14
large biomolecules.
Comparison of the experimental VCD and infrared
absorption spectra of (+)-8 with their corresponding
simulations, which are based on ab initio calculations,
are shown in Fig. 2. The optimized geometry used for
ab initio calculation is shown in Fig. 3. Very good
agreement for the signs as well as positions of the VCD
patterns between experimental and simulated spectra
clearly confirms the 1R,3R,6R,8R-configuration of the
compound presented in Fig. 3. In addition, convincing
agreement between experimental and calculated spectra
enables the detailed assignment of vibrational bands
(
Table 1), which are based on the dynamic visualization
of individual vibrational modes. A detailed inspection
of Fig. 2 shows the advantage of VCD spectra: the
existence of +/− signs causes better resolution of VCD
bands as compared with IR absorption.
Figure 1. Experimental ECD spectrum of (+)-8 in CHCl
3
−
3
−1
3
−1
−1
(
c=7.8×10 mol L ): u
(Dm/dm mol cm ) <235 (posi-
max
tive), 279 (−1.26), 419 (+0.78).
to be additive; however, the way in which different
parts of a molecule interact to generate the resulting
sign and magnitude of the CE is still debated. It was
suggested that the sign of the long-wavelength CE for
the planar a-diketone and related chromophores could
2c
be predicted by the antioctant sector rule.
Thus, the ECD of (+)-8 spectrum exhibited the two low
energy n-p* CD bands, one below 300 nm and the
other above 400 nm as for other 1,2-diketones. This is
a result of coupling and splitting of two n-p* transi-
tions. The relevant band at 420 nm arises from the
interaction of two carbonyl chromophores. The twist-
ing of the HOMO of this molecule is shown in Fig. 3,
where the angle between chromophores is approxi-
mately 17°. The relation of the helicity of the chro-
11
mophores in 1,2-diketones has been considered. In
case of structure 8 the chirality of this 1,2-dione is
right-handed when the CE sign of the n-p* transition
above 400 nm is negative. Thus, following the above-
mentioned relationship the 1S,3S,6S,8S-configuration
should be assigned to (+)-8, which is in disagreement
with the configuration assigned by chemical correlation.
Consequently, this example demonstrates that semi-
empirical rules should be employed very cautiously.
The absolute configuration of compound (+)-8 was
12
confirmed using VCD spectroscopy. The commercial
availability of the VCD technique in the last five years
balanced the previous advantage of the more wide-
spread ECD spectroscopy. VCD, which represents the
application of circular dichroism to the vibrational
transitions, has good theoretical background, which
enables the assignment of the intensity features to indi-
vidual vibration modes and, in the case of characteristic
vibrations, to atoms of functional groups. Ab initio
calculations of VCD spectra and the assignment of
experimental VCD bands and their comparison with
Figure 2. Experimental and calculated VCD (A), and absorp-
tion (B) spectra of (+)-8, noise spectrum (N). The intensity of
the absorption spectra in the region 1800–1600 cm is
−
1
divided by 4.

6
36
E. Butkus et al. / Tetrahedron: Asymmetry 13 (2002) 633–638
4
. Experimental and computations
Melting and boiling points are uncorrected. IR spectra
were recorded in KBr pellets on a Perkin–Elmer Spec-
1
trum BX spectrometer. H NMR spectra were recorded
on Bruker (200 MHz) and Tesla BS-587A instruments
in deuterated chloroform unless otherwise stated and
are reported as chemical shifts (l) in ppm relative to
(
CH ) Si. Mass spectra were run by GC–MS on a
3 4
Hewlett–Packard 6980 instrument with mass selective
detector HP 5973 using Supelcowax capillary column
(
30 m×0.25 mm). GLC analysis was carried out on a
Varian 3700 instrument (FID) by using 30 m long
column (9% silicon on Chromosorb W-AW). A Perkin–
Elmer Autosystem GC equipped with split/splitless
injector and flame ionization detector was used for
analytical separation on BetaDex 120 fused silica capil-
lary column. The ECD spectra were recorded with a
Jobin Yvon Mark V spectrometer at 20°C in a 0.1 cm
−
3
cell using chloroform as a solvent (c=7.8×10 mol
−
1
L ). Optical rotations were measured in a 10 cm cell
on a polarimeter Polamat-A (Carl Zeiss) at 546 nm.
Thin-layer chromatography was carried out on
Kieselgel 60 F254 (Merck) sheets coated with silica gel
and silica gel Kieselgel 60 (0.040–0.063 mm, Merck)
was used for column chromatography. The VCD and
infrared absorption spectra were measured at a resolu-
Figure 3. HOMO (top) and optimized geometry of (+)-8 used
for ab initio calculation.
−
1
tion of 4 cm using a Bruker FT-IR IFS 66/S spec-
trometer equipped with the VCD/IRRAS module PMA
Table 1. Assignment of VCD and absorption bands in the
mid IR region, the mode labels are the same as in Fig. 2
15
37 as described in detail elsewhere. The CDCl solu-
3
tions of samples were placed in a demountable cell
A145 (Bruker, Germany) constructed from KBr win-
dows separated by a 0.1 mm Teflon spacer. VCD
spectra were obtained as an average of three blocks,
each measured for 0.5 h as co-addition of 3320 interfer-
ometric scans. The VCD baseline was obtained as a
spectrum of pure solvent. The noise spectra were calcu-
lated as a half of the difference between two blocks of
scans. The concentration used for VCD measurements
Mode VCD and absorption frequencies
Assignment
−
1
(cm
)
Calculated
Experimental
1
2
3
4
5
6
7
8
9
1
1
1
1
1
1
1
1771.2
1743.3
1487.6
1467.5
1293.7
1283.5
1249.5
1235.8
1226.3
1190.7
1179.8
1138.6
1084.6
1027.3
1022.8
960.2
1758
1743
1492
1470
1310
1295
1264
1255
1251
1218
1194
1153
1113
1064
1047
977
CꢀO of phase
CꢀO in phase
CH2 scissoring
CH2 scissoring
CH2 wagging
CH2 wagging
CH2 wagging
CH2 wagging
CH bend
C(O)ꢁC(O) stretch
CꢁC stretch
CH2 wagging
CꢁC stretch
CH bend
−
1
was 0.5 mol L . Because of significantly higher molar
−
1
absorptivity in carbonyl region (1800–1600 cm ),
which is not favorable for VCD measurements, the
carbonyl VCD pattern was proved also by measure-
−1
ments of solution with concentration of 0.1 mol L .
0
1
2
3
4
5
6
A simulation of the VCD intensities based on the
16
Gaussian program package
was performed for
geometries optimized with the aid of the conformer
searching routine implemented in the Spartan pro-
C(O)ꢁC(O) stretch
C(O)ꢁC(O) stretch
17
gram. Vibrational frequencies and intensities were
18
calculated at the BPW91/6-31+G** DFT level at the
harmonic approximation using the MFP/GIAO
1
9
theory
for VCD. Spectra were simulated using
−1
Lorentzian profiles with the 5 cm bandwidth. Normal
mode assignment is based on a visual inspection of the
dynamic displacements.
3. Conclusions
3
,8
The synthesis of chiral (+)-tricyclo[4.3.0.0 ]nonane-4,5-
4
.1. (+)-(1S,5S)-Bicyclo[3.3.1]nonane-2,6-dione 1
dione was accomplished from enantiomerically pure
(
+)-(1S,5S)-bicyclo[3.3.1]nonane-2,6-dione. The chirop-
Baker’s yeast (6.0 g) and saccharose (72 g) were sus-
pended in water (140 mL). Racemic bicyclo-
tical properties of this cage molecule were studied by
ECD and VCD spectroscopy and the 1R,3R,6R,8R
absolute configuration of the structure was proved.
[
3.3.1]nonane-2,6-dione 2 (3 g) was added after 30 min
and the mixture was stirred for 6 days. The yeast

E. Butkus et al. / Tetrahedron: Asymmetry 13 (2002) 633–638
637
was removed after centrifugation of the mixture and the
products were isolated by continuous extraction with
ether. The mixture of products was dissolved in
dichloromethane and the butanedioic acid formed dur-
ing the metabolism of yeast was filtered off. Column
chromatography of the product with petrol ether–ethyl
acetate (2:1) afforded (+)-1 (1.75 g, 24%) with e.e. 93%,
for C H O : C, 58.69; H, 6.57. Found: C, 58.72; H,
6.66%.
9
12
4
4
.5. (+)-(1R,2R,4R,5R)-Dimethyl-endo,endo- and
endo,exo-bicyclo[2.2.1]heptan-2,5-dicarboxylates 5
and 6
18
hydroxyketone (3.4 g), and diol (0.36 g). (+)-1: [h]5
46
A mixture of dicarboxylic acid (1.26 g, 6.7 mmol) (+)-3
and thionyl chloride (7 mL, 9.5 mmol) was heated
under reflux for 2 h and then bromine (5.16 g, 32
mmol) was added. The reaction mixture was heated
under reflux for 3 days. To a cooled reaction mixture,
benzene (15 mL) was added and the mixture was evap-
orated in vacuo. The solid residue (2.25 g) was dis-
solved in anhydrous methanol (35 mL) and heated
under reflux for 6 h. The solvent was evaporated and to
the residue dissolved in glacial acetic acid (20 mL) zinc
4
+
204.0 (dioxane, c 0.05) (lit.: [h] +203.8 (dioxane),
D
e.e. 93%).
4
.2. (+)-(1R,2S,4R,5S)-exo,exo-Dimethylbicyclo[2.2.1]-
heptan-2,5-dicarboxylate 2
A solution of (+)-1 (1.75 g, 11.5 mmol) in anhydrous
methanol (110 mL) was treated with a solution of TTN
(
9.1 g, 23.2 mmol) in methanol (60 mL). The reaction
mixture was stirred for 16 h and the solid was filtered
off. The major volume of methanol was evaporated and
the residue was treated with acidified water (3 mL of
(
6.5 g, 100 mmol) was added in portions during 1 h.
The reaction mixture was stirred for 6 h, then water
100 mL) was added and the mixture was left overnight.
(
HCl in 70 mL of H O). The resulting mixture was
2
The product was extracted into chloroform (3×35 mL),
the combined organic phases were washed with sodium
hydrocarbonate solution, dried over Na SO and con-
extracted with chloroform (3×70 mL). The solvent was
evaporated and the residue distilled in vacuo yielding
2
0
2
4
diester 2 (2.1 g, 85%), bp=119–120°C/4 mmHg, n =
D
centrated to yield a mixture of diesters 5 and 6. Column
chromatography on silica gel (elution with benzene)
gave the individual esters.
1
6
−1
1
7
.4760; [h] +40.0 (CHCl , c 0.1); IR wmax/cm 1728,
546 3
1
30; H NMR: l 1.40 (2H, m, C -H), 1.48 (2H, d,
7
J=9.0 Hz, C (C )-H ), 1.70–1.98 (2H, m, C (C )-
3
6
endo
3
6
Hexo), 2.1–2.28 (2H, dd, J=5.5 and 9.0 Hz, C (C )-H),
2
5
5
: (R =0.64), yield 0.53 g (38%), bp 95–96°C/3 mmHg,
f
21 −1 1
13
2
.45 (2H, d, J=4 Hz, C (C )-H), 3.52 (6H, s, CH );
C
1
4
3
[
h]5 +32.5 (CHCl , c 0.08); IR wmax/cm 1735; H
46 3
NMR: l 33.5, 34.2, 40.2, 45.2, 51.3, 175.7 (CꢀO), (all
skeletal C). MS (relative intensity) m/z 212 (19), 180
NMR: l 1.38–1.63 (6H, m), 2.38–2.75 (4H, m), 3.57
13
(
6H, s); C NMR: l 26.8, 40.3, 41.0, 45.5, 51.3, 174.1
(
15), 152 (14), 120 (9), 86 (100). Anal. calcd for
(
CꢀO). Anal. calcd for C H O : C, 62.26; H, 7.60.
11
14
4
C H O : C, 62.26; H, 7.60. Found: C, 61.95; H,
11
14
4
Found: C, 62.22; H, 7.54.
7.56%.
6
: (R =0.45), yield 0.33 g (26%), mp 64–66°C, IR
f
−1 1
4
.3. Epimerization of (+)-exo,exo-dimethylbicyclo-
wmax/cm 1730; H NMR: l 1.23–1.87 (6H, m), 2.13–
[
2.2.1]heptan-2,5-dicarboxylate
13
2
.75 (4H, m), 3.50 (6H, s); C NMR: l 29.4, 32.0, 38.4,
4
0.3, 41.6, 45.7, 51.6, 51.7, 175.0, 176.0 (CꢀO). Anal.
To a solution of (+)-2 (0.3 g, 12.4 mmol) in anhydrous
methanol (0.5 mL) was added sodium methoxide (0.15
g, 18.5 mmol) and the mixture was heated in sealed
tube at 100–105°C for 40 h. The reaction mixture was
cooled, the contents of the tube dissolved in water (5
mL) and extracted with ether (3×5 mL). The extracts
were combined, washed with water and dried over
Na SO , solvent evaporated and the residue distilled in
calcd for C H O : C, 62.26; H, 7.60. Found: C, 62.18;
H, 7.63%.
11
14
4
3,8
4.6. (+)-(1R,3R,6R,8R)-Tricyclo [4.3.0.0 ]nonane-4,5-
dione 8
A solution of trimethylchlorosilane (1.95 g, 18 mmol)
and diester 5 (0.33 g, 1.55 mmol) in toluene (15 mL)
was added dropwise to a boiling and vigorously stirred
mixture of sodium (0.31 g, 13.5 mmol) in dry toluene
2
4
vacuo (bp 119–120°C/4 mmHg) to yield a mixture of
esters (0.28 g), consisting according to GC–MS of
exo,exo- and exo,endo-isomers in ratio 85:15.
(
50 mL). The reaction mixture was refluxed and stirred
4.4. (+)-(1R,2S,4R,5S)-exo,exo-Bicyclo[2.2.1]heptan-
2,5-dicarboxylic acid 3
for 3 h under a nitrogen atmosphere, filtered and
solvent evaporated. The residue was dissolved in tetra-
chloromethane (40 mL) and an excess of 5% solution of
A solution of (+)-2 (1.7 g, 9 mmol) in dilute (1:1)
hydrochloric acid (60 mL) was heated under reflux for
bromine in CCl was added in portions. The reaction
4
mixture was concentrated and the obtained oily
product was purified by column chromatography (elu-
ent chloroform) to yield 0.07 g (30%) mp 72–74°C.
3
h. The reaction mixture was evaporated till dryness.
The solid was recrystallized from ethanol–benzene
yielding diacid 3 (1.4 g, 95%), mp 228–230°C; [h]
1
6
16
3
−1
[h] +207.5 (CHCl , c 0.07); CD: u
(Dm/dm mol
5
46
546
−1
3
max
−
1
+
44.0 (C H OH, c 0.043); IR wmax/cm 1705, 3200 (br);
cm ) <235 (positive), 279 (−1.26), 419 (+0.78); IR
2
5
1
−1
1
H NMR (CD OD) l 1.33 (2H, s), 1.43 (2H, m, C3
wmax/cm 1760, 1743; H NMR: l 1.38–1.63 (6H, m),
13
3
(
C )-H ), 1. 81 (2H, m, C (C )-H ), 2.26 (2H, m,
2.38–2.75 (4H, m), 3.57 (6H, s); C NMR: l 26.8, 40.3,
41.0, 45.5, 51.3, 174.1 (CꢀO). Anal. calcd for C H O :
6
endo
3
6
exo
3
1
C (C )-H); 2.46 (2H, m, C (C )-H); C NMR: l 34.7,
2
5
1
4
9
10
2
35.4, 41.9, 179.1 (CꢀO), (all skeletal C). Anal. calcd
C, 71.98; H, 6.71. Found: C, 72.31; H, 7.05%.

6
38
E. Butkus et al. / Tetrahedron: Asymmetry 13 (2002) 633–638
9. Levy, G. C.; Lichter, R. L.; Nelson, G. L. Carbon-13
Acknowledgements
Nuclear Magnetic Resonance; John Wiley and Sons: New
York, 1980.
10. An access to Advanced Chemistry Development (ACD
Labs) at http://www.acdlabs.com granted to S.S.
11. Burgstahler, A. W.; Naik, N. C. Helv. Chim. Acta 1971,
This work was supported by grants of the Ministry of
Education, Youth and Sports (CEZ: MSM 223400008),
Academy of Sciences of the Czech Republic
(
IAA4055104), the Grant Agency of the Czech Repub-
lic (203/02/0328) and in part by the Lithuanian science
and studies foundation. E.B.’s visit to Prague Institute
of Chemical Technology in the frame of the bilateral
agreement between the Czech Republic and Lithuania
is acknowledged. We thank M. Hassman for the assis-
tance with the measurement of the ECD spectrum.
5
4, 2920–2924.
1
2. (a) Keiderling, T. A. In Practical Fourier Transform
Infrared Spectroscopy; Ferraro, J. R.; Krishnan, K., Eds.;
Academic Press: San Diego, 1990; pp. 203–284; (b) Nafie,
L. A.; Freedman, T. B. In Circular Dichroism Principles
and Applications; Berova, N.; Nakanishi, K.; Woody, R.
W., Eds.; John Wiley and Sons: New York, 2000; pp.
9
7–132.
3. (a) Stephens, P. J.; Devlin, F. J. Chirality 2000, 12,
72–179; (b) Bou rˇ , P.; McCann, J.; Wieser, H. J. Phys.
References
1
1
1
2
. Lightner, D. A. In Circular Dichroism: Principles and
Applications; Berova, N.; Nakanishi, K.; Woody, R. W.,
Eds., 2nd ed.; John Wiley and Sons: New York, 2000; pp.
Chem. A 1998, 102, 102; (c) Solladi e´ -Cavallo, A.; Sedy,
O.; Salisova, M.; Biba, M.; Welch, C. J.; Nafi e´ , L. A.;
Freedman, T. B. Tetrahedron: Asymmetry 2001, 12, 2703–
2
61–303.
. (a) Hug, W.; Wagniere, G. Helv. Chim. Acta 1971, 54,
33; (b) Burgstahler, A. W.; Barkhurst, R. C. J. Am.
2
707; (d) Devlin, F. J.; Stephens, P. J.; Scafato, P.;
Superchi, S.; Rosini, C. Tetrahedron: Asymmetry 2001,
2, 1551–1558; (e) Setni cˇ ka, V.; Urbanov a´ , M.; Bou rˇ , P.;
Kr a´ l, V.; Volka, K. J. Phys. Chem. A 2001, 105, 8931–
938; (f) Bou rˇ , P.; Navr a´ tilov a´ , H.; Setni cˇ ka, V.;
Urbanov a´ , M.; Volka, K. J. Org. Chem. 2002, 67, 161–
68.
6
1
Chem. Soc. 1970, 92, 7601–7603; (c) Polonski, T.;
Milewska, M. J.; Gdaniec, M. Tetrahedron: Asymmetry
8
2
000, 11, 3113–3122.
3
. (a) Osawa, E.; Schneider, I.; Toyne, K. J.; Musso, H.
Chem. Ber. 1986, 119, 2350–2361; (b) Gleiter, R.; Herb,
T.; Lange, H. J. Org. Chem. 1996, 61, 9236–9241; (c)
Gleiter, R.; Herb, T.; Borzyk, O.; Hyla-Krypsin, I.
Liebigs Ann. Org. Bioorg. Chem. 1995, 2, 357–364.
1
14. (a) Silva, R. A. G. D.; Kubelka, J.; Bou rˇ , P.; Decatur, S.
M.; Keiderling, T. A. Proc. Natl. Acad. Sci. USA 2000,
9
7, 8318–8323; (b) Bou rˇ , P.; Z a´ ruba, K.; Urbanov a´ , M.;
Setni cˇ ka, V.; Mat eˇ jka, P.; Fiedler, Z.; Volka, K. Chirality
000, 12, 191–198.
5. Urbanov a´ , M.; Setni cˇ ka, V.; Volka, K. Chirality 2000,
2, 199–203.
4. Hoffmann, G.; Wiartalla, R. Tetrahedron Lett. 1982, 23,
2
3
887–3888.
1
1
5
. For a review on the use of thallium(III) for oxidative
rearrangements, see: Ferraz, H. M. C.; Silva, L. F., Jr.; de
Vieira, T. O. Synthesis 1999, 2001–2023.
. Irwin, A. J.; Jones, J. B. J. Org. Chem. 1977, 42, 2176–
2
1
6. Frisch, M. J.; and col. Gaussian 98; Gaussian Inc.: Pitts-
burgh, PA, 1998.
17. Spartan, P. C. PC Spartan Pro 2000, Pro 1.0.5; Wave-
function Inc.: Irvine, 2000.
18. Becke, A. D. J. Chem. Phys. 1993, 98, 5648–5652.
19. Devlin, F. J.; Stephens, P. J.; Cheeseman, J. R.; Frisch,
M. J. J. Phys. Chem. A 1997, 101, 9912–9924.
6
7
8
177.
. Bird, C. W.; Cooper, R. Org. Prep. Proceed. Int. 1993,
5, 237–240.
. McKillop, A.; Hunt, J. D.; Taylor, E. C. J. Org. Chem.
972, 37, 3381–3382.
2
1