Sugar allyltins in the synthesis of carbobicycles. Preparation of highly oxygenated enantiomerically pure decalins

Article abstract of DOI:10.1016/S0957-4166(01)00288-9

Readily available unsaturated bicyclic ketones-obtained conveniently from sugar allyltins-are converted into highly oxygenated unsaturated decalins. The corresponding cis- and trans-diols resulting from oxidation of the double bond were obtained with 100% selectivity. Stereospecific introduction of nitrogen into the decalin system via azidation was also realized.

Full text of DOI:10.1016/S0957-4166(01)00288-9

TETRAHEDRON:
ASYMMETRY
Pergamon
Tetrahedron: Asymmetry 12 (2001) 1651–1656
Sugar allyltins in the synthesis of carbobicycles. Preparation of
highly oxygenated enantiomerically pure decalins
Sławomir Jarosz* and Stanisław Sko´ra
Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44, 01-224 Warszawa, Poland
Received 1 June 2001; accepted 21 June 2001
Abstract—Readily available unsaturated bicyclic ketones—obtained conveniently from sugar allyltins—are converted into highly
oxygenated unsaturated decalins. The corresponding cis- and trans-diols resulting from oxidation of the double bond were
obtained with 100% selectivity. Stereospecific introduction of nitrogen into the decalin system via azidation was also realized.
© 2001 Elsevier Science Ltd. All rights reserved.
1. Introduction
Recently we elaborated a convenient route to sugar
allyltin derivatives 1 from simple monosaccharides.1–3
Irrespective of the (E)- or (Z)-configuration of the
starting allyltin reagent 1,2,3 these derivatives were con-
verted into trans-dienoaldehydes 2 upon treatment with
zinc chloride. Aldehydes 2 are useful starting materials
for the preparation of bicyclo[4.3.0]nonene4 4 and bicy-
clo[4.4.0]decene5 3 systems.
2. Results and discussion
The methodology shown in Scheme 1 opens a conve-
nient route to enantiomerically pure carbobicyclic
derivatives. Herein, a study on the functionalization of
decalin precursor obtained from sugar allyltin
reagents is presented.
Highly oxygenated bicyclo[4.3.0]nonanes and bicy-
clo[4.4.0]decanes are known to possess interesting bio-
logical activities. One of the stereoisomers of decalin 5
has shown potent and selective a-glucosidase inhibition
at mM concentration against a- and b-glucosidases.6
However, compounds of this type are available only in
racemic form.7
a
Decalone 65 was selected as a model compound for this
study. Reduction of 6 under standard conditions
(NaBH4) afforded alcohol 7 as a single stereoisomer.
Scheme 1. (i) Refs. 2 and 3: ZnCl2, methylene chloride, rt, 2 h; (ii) Ref. 5: [O], then CH2N2, then H2CꢀP(O)(OMe)2; (iii) Ref. 5.
RCHO, K2CO3, 18-crown-6, toluene, rt; (iv) Ref. 4.
* Corresponding author. Fax: (48-22) 632-66-81; e-mail: sljar@icho.edu.pl
0957-4166/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved.
PII: S0957-4166(01)00288-9

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S. Jarosz, S. Sko´ra / Tetrahedron: Asymmetry 12 (2001) 1651–1656
The configuration at the C(1) stereogenic center in 7 was
easily assigned from the 1H NMR spectrum of its acetate,
in which the large coupling constant between C(1)H and
C(2)H (C(1)H lH 5.05, dd, J1,2=8.7, J1,10=3.5 Hz)
pointed unambiguously at the trans arrangement of these
protons. Standard osmylation of the double bond8
afforded (after acetylation) compound 9 again as a single
isomer. The configuration of 9 was easily deduced from
its 1H NMR spectrum in which the large coupling
constant J7,8a=12.1 Hz was seen (Scheme 2).
Since the free hydroxy group present in 10 or 11 induces
undesired side reactions (e.g. formation of 13) during
functionalization of the oxirane ring, we decided to
protect the 1-OH in 7 as its benzyl ether. Compound 8
obtained by standard benzylation of 7 was epoxidized (as
described for 7) to afford two stereoisomers 14 and 15
in 79% yield and in 2:1 ratio (Scheme 2). Configuration
of these epoxides were assigned by comparison of their
NMR spectra with the corresponding data for 10 and 11.
The most diagnostic were the J5,6 coupling constant values
assigned as 2.6 Hz (for 10 and 14) and ca. 5 Hz (for 11
and 15).
Epoxidation using m-chloroperbenzoic acid was much
less selective; two stereoisomeric oxiranes 10 and 11 were
obtained in a 1:1 ratio (Scheme 2). The assignment of the
configuration of both oxiranes was based on NOE
Attempts to izomerize these epoxides (having protected
C(1)OH group) into allylic alcohols failed; both oxiranes
were unreactive towards LDA.
1
experiments in H NMR (see Scheme 2). Attempts to
isomerize these epoxides to allylic alcohols (e.g. 12 from
11 or its C(6) epimer from 10) with LDA9 failed.
Compound 11 was completely unreactive, but stereoiso-
mer 10 underwent intramolecular opening of the oxirane
ring (exclusively at C(6)) with the anion generated from
C(1)OH to afford tricyclic compound 13 (Scheme 2).†
Configuration of this derivative was assigned on the basis
of the NMR spectrum of its acetate in which the 1H–1H
correlations between the low-field signal of C(7)H (l=
4.77) to both C(8)H were seen.
Opening of the oxirane ring in both epoxides 14 and 15
was highly stereoselective. Attack of the azide anion on
14 afforded exclusively compound 16, while the same
reaction performed on 15 gave 18 as a single isomer. The
configurations of both azides (precursors of amines) were
1
easily assigned from the H NMR spectra of acetylated
products; the C(6)H resonance in 16-Ac was observed at
l=5.35 ppm, while that in 18-Ac at l=4.23 ppm.
Scheme 2. (i) NaBH4, THF/MeOH, 93%; (ii) OsO4, NMO (cat.), then Ac2O, 74%; (iii) BnBr, NaH, DMF, 93%; (iv). MCPBA;
(v) LDA, THF, −78 to 0°C, then Ac2O; (vi) NaN3, DMF; (vii) AcONa, AcOH, DMF, 100°C, 20 h; (viii) Ac2O.
† This result pointed unequivocally to a trans-relationship between the oxirane ring and the C(1)OH group in 11, thus proving assignment of the
configuration based on NOE experiments.

S. Jarosz, S. Sko´ra / Tetrahedron: Asymmetry 12 (2001) 1651–1656
1653
Reaction of the epoxides with acetate anion was more
complex. Treatment of 14 with AcONa/AcOH10 pro-
vided 66% of the trans isomer 17 and 17% of the
monoacetate, which was identified as 19! Final proof
for this structure came from the acetylation experiment
performed on both regioisomers—the same di-acetate
20 was obtained. Formation of compound 19 during
opening of the oxirane ring in 14 might be explained by
a migration of the acetate group from the O-7 to O-6
position. This assumption was verified experimentally;
treatment of either pure 17 or pure 19 under the
reaction conditions (AcONa/AcOH, 100°C, 20 h) led to
a mixture of both compounds. Treatment of epoxide 15
with acetate afforded also both isomers 19 and 17,
which were converted into diacetate 20 by simple acetyl-
ation in 79% overall yield. No formation of the alterna-
tive (6R,7R) isomer was observed (Scheme 2).
ent arrangement of reacting centers during such
intramolecular process.
Deprotection of such highly oxygenated, enantiomeri-
cally pure decalins was possible in good overall yield as
exemplified by conversion of compound 9 into the
octaacetate 22 (Scheme 3).
The isopropylidene group was removed with sulfuric
acid and the resulting diol was acetylated to afford
pentaacetate 21 in 83% yield. This compound was
subjected to hydrogenation over Pd/C in the presence
of catalytic amounts of acetic acid (without the acid the
benzyl blocks were stable towards hydrogenation) and
the resulting product was acetylated affording octa-
acetate 22 in 90% yield (75% overall from 9).
The high selectivity observed in the opening of the
oxirane ring in 14 and 15 may be explained by the
preferred axial attack of the nucleophile, as presented
in Fig. 1.
3. Conclusions
Optically pure decalins such as 6 are easily prepared
from sugar allyltin derivatives. These compounds con-
tain synthetically useful units which can be transformed
into polyhydroxy decalins with very high selectivity.
The stereospecific introduction of nitrogen is also possi-
ble. Deprotection of such highly oxygenated decalins
can be performed easily and in good yields under
standard conditions. Further work on the transforma-
tion of bicyclic precursors obtained from sugar allyltins
and their biological evaluation is currently in progress.
In the light of these results, formation of the tricyclic
compound 13 deserves discussion. Attack of the free
hydroxy group (at C(1)) occurring on the C(6) position
(and not C(7), as in the intermolecular opening of the
oxirane ring in 14) results, most likely, from the differ-
4. Experimental
4.1. General
NMR spectra were recorded with a Bruker AM 500
spectrometer for solutions in CDCl3 (internal Me4Si)
unless otherwise stated. All resonances were assigned by
COSY (1H–1H and 1H–13C) and DEPT correlations.
The relative configurations of the protons were deter-
mined by NOE or NOESY experiments. Mass spectra
(ESI) were recorded with a PE SCIEX API 365 or
Mariner PerSeptive Biosystems apparatus. Specific
rotations were measured with a JASCO DIP Digital
Polarimeter using chloroform solutions (cꢀ1.5) at
room temperature. Column chromatography was per-
formed on silica gel (Merck, 70–230 and 230–400
mesh). Organic solutions were dried over anhydrous
sodium sulfate. (2R,3S,4R,5S,9S,10R)-{1-Keto-2,3,4-
Figure 1. The preferred attack of the nucleophile on
stereoisomeric epoxides.
Scheme 3. (i) 1. THF/H2O, H2SO4, reflux, 12 h; (ii) Ac2O/py; (iii) H2/Pd, AcOEt/EtOH, cat. AcOH, rt, overnight.

1654
S. Jarosz, S. Sko´ra / Tetrahedron: Asymmetry 12 (2001) 1651–1656
tri-benzyloxy-6,7-ene-9-[(1%S)-5,5-dimethyl-2,4-dioxol-
ane-1%-yl]}decalin 6 was prepared according to Ref. 5.
at room temperature and partitioned between brine and
ethyl acetate. The product was isolated by column
chromatography (hexane:ethyl acetate, 1:6); yield of 9
121 mg (74%); HRMS [ESI] m/z: 627.2997
[C36H44O8Na (M+Na+) requires 627. 2928]. Anal. calcd
for C36H44O8: C, 71.50; H, 7.33. Found: C, 71.23; H,
7.40%.
4.2. Functionalization of the carbonyl group in 6
4.2.1. (1R,2S,3S,4R,5S,9S,10R)-{1-Hydroxy-2,3,4-tri-
benzyloxy-6,7-ene-9-[(1%S)-5,5-dimethyl-2,4-dioxolane-1%-
yl]}decalin 7. Ketone 6 (150 mg, 0.26 mmol) was
dissolved in MeOH (6 mL), THF (5 mL) and water (3
mL) and the mixture treated with sodium borohydride
(15 mg, 1.5 equiv.) and stirred at room temperature for
30 min. The mixture was concentrated, the crude
product was extracted with ethyl acetate and purified
by column chromatography (hexane:ethyl acetate, 5:1)
to afford 7 as an oil (140 mg, 93%). HRMS m/z:
593.2928 [C36H42O6Na (M+Na+) requires 593.2874].
Anal. calcd for C36H42O6: C, 75.76; H, 7.42. Found: C,
75.52; H, 7.22%.
This compound was further characterized as its tri-
acetate derivative: [h]D=−13.7; 1H NMR l: 5.71 (J5,6
ꢀ
3 Hz, H-6), 5.04 (ddd, J6,7 3.1, J7,8 4.5, J7,8a 12.1, H-7),
4.93 (dd, J1,10 3.9, J1,2 10.8, H-1), 4.61 (m, H-1%), 3.81
(dd, J2,3 9.0, H-2), 3.73 (m, H-4, 2%,2%a), 3.59 (dd, J3,4
8.8, H-3), 2.22 (m, H-9), 2.08 (m, H-5,8,10), 2.08, 1.98
and 1.94 (3×CH3CO2), 1.53 (m, H-8a), 1.44 and 1.34
[C(CH3)2]; 13C NMR l: 170.0, 169.6 and 169.4 (3×
CꢀO), 108.6 [C(CH3)2], 87.2, 78.7, 78.0, 74.4, 74.3, 68.7,
67.6 (C-1,2,3,4,6,7,1%), 75.7, 75.5 and 75.2 (3×CH2Ph),
63.9 (C-2%), 44.4, 36.5 and 35.7 (C-5,9,10), 25.9 and 24.5
[C(CH3)2], 24.7 (C-8), 21.2, 21.0 and 20.9 (3×CH3CO2).
Compound 7 was further characterized as its acetate
derivative. [h]D=+91.5; 1H NMR l: 5.89 (m, H-6), 5.71
(m, H-7), 5.05 (dd, J1,10 3.5, J1,2 8.7, H-1), 4.35 (m,
H-1%), 3.87 (dd, J1%,2% 6.6, J2%,2%a 8.2, H-2%), 3.85 (dd, J2,3
8.3, H-2), 3.65 (dd, J3,4 9.4, H-3), 3.60 (dd, J1%,2%a 6.5,
H-2%a), 3.57 (t, J4,5 9.4, H-4), 2.41 (m, H-5), 2.21 and
1.76 (2×m, both H-8), 2.15 (m, H-9 and H-10), 1.96
(CH3CO2), 1.43 and 1.33 [C(CH3)2]; 13C NMR l: 169.9
(CꢀO), 128.1 (C-6), 126.4 (C-7), 108.5 [C(CH3)2], 86.5
(C-3), 83.7 (C-4), 80.4 (C-2), 76.2 (C-1%), 75.5, 75.3 and
74.2 (3×CH2Ph), 75.3 (C-1), 65.9 (C-2%), 39.4 (C-5), 37.5
and 36.0 (C-9,10), 26.3 and 24.9 [C(CH3)2], 25.8 (C-8),
21.3 (CH3CO2).
4.4. Epoxidation reaction of unsaturated decalins
4.4.1. Reaction of 7 with m-chloroperbenzoic acid. To a
solution of olefin 7 (770 mg, 1.35 mmol) in methylene
chloride (30 mL) was added MCPBA (500 mg, 85%
purity, 2.7 mmol) and the mixture was kept at room
temperature for 24 h. Ether (100 mL) was added, the
organic layer was washed with 0.5% NaOH, water,
dried, concentrated, and the products 10 (330 mg, 42%)
and 11 (350 mg, 44%) were isolated by column chro-
matography (hexane:ethyl acetate, 4:1“2:1).
4.4.1.1. (1R,2S,3S,4R,5R,6S,7R,9S,10R)-{6,7-Anhy-
dro-1-hydroxy-2,3,4-tri-benzyl oxy-9-[(1%S)-5,5-dimethyl-
2,4-dioxolane-1%-yl]}decalin 10. HRMS m/z: 609.2827
[C36H42O7Na (M+Na+) requires 609.2823]. Anal. calcd
for C36H42O7: C, 73.70; H, 7.22. Found: C, 73.51; H,
7.28%. [h]D=+68.4; 1H NMR l: 4.24 (dd, J1%,2% 6.3,
H-1%), 3.97 (dd, J2%,2%a 8.5, H-2%), 3.69–3.57 (m, H-
2,3,4,2%a), 3.54 (m, H-1), 3.49 (d, J1,OH 5.8, OH), 3.44
(dd, J5,6 2.6, J6,7 4.0, H-6), 2.92 (t, J6,7=J7,8 4.0, H-7),
2.28 (ddd, J4.5 11.0, J5.10 4.0, H-5), 2.01 (m, H-10), 1.91
(m, H-8), 1.85 (m, H-9), 1.61 (m, H-8a), 1.40 and 1.32
[C(CH3)2]. 13C NMR l: 108.8 [C(CH3)2], 87.3, 87.1,
79.2, 77.3 and 74.4 (C-1,2,3,4,1%), 75.8, 75.3 and 75.1
(3×CH2Ph), 66.9 (C-2%), 53.6 and 51.0 (C-6,7), 39.2,
36.9 and 33.2 (C-5,9,10), 26.3 and 25.3 [C(CH3)2], 24.3
(C-8). NOE: H5-H6 (5.3%).
4.2.2. (1R,2S,3S,4R,5S,9S,10R)-{1-2,3,4-Tetra-benzyl-
oxy-6,7-ene-9-[(1%S)-5,5-dimethyl-2,4-dioxolane-1%-yl]}-
decalin 8. Benzylation (BnBr, NaH, DMF) of alcohol 7
afforded 90% of 8 which was isolated as an oil by
column chromatography (hexane:ethyl acetate, 8:1);
1
[h]D=+87.8; H NMR l: 5.89 (m, H-6), 5.75 (m, H-7),
4.77 (m, H-1%), 3.87 (dd, J1,2 9.6, J2,3 8.6, H-2), 3.76 (dd,
J1%,2% 7.1, J2%,2%a 8.6, H-2%), 3.62 (dd, J1%,2%a 5.4, H-2%), 3.57
(m, H-3,4), 3.53 (dd, J1,10 4.3, H-1), 2.32 (m, H-8), 2.22
(m, H-5, H-9), 1.95 (ddd, J9,10 11.2, J5,10 4.8, H-10),
1.81 (m, H-8a), 1.41 and 1.25 [C(CH3)2]; 13C NMR l:
128.3–127.3 (C-6,7 and C arom.), 107.9 [C(CH3)2], 86.8,
84.6, 82.9, 82.1 and 75.7 (C-1,2,3,4,1%), 75.6, 75.5, 75.3
and 74.4 (4×CH2Ph), 65.0 (C-2%), 40.4, 39.4 and 35.2
(C-5,9,10), 26.0 and 24.2 [C(CH3)2], 25.8 (C-8). Anal.
calcd for C43H48O6: C, 78.15; H, 7.32. Found: C, 78.10;
H, 7.43%.
4.4.1.2. (1R,2S,3S,4R,5R,6R,7S,9S,10R)-{6,7-Anhy-
dro-1-hydroxy-2,3,4-tri-benzyl oxy-9-[(1%S)-5,5-dimethyl-
2,4-dioxolane-1%-yl]}decalin 11. HRMS m/z: 609.2828
[C36H42O7Na (M+Na+) requires 609.2823]. Anal. calcd
for C36H42O7: C, 73.70; H, 7.22. Found: C, 73.80; H,
4.3. cis-Hydroxylation of 7:
(1R,2S,3S,4R,5R,6S,7R,9S,10R)-{1,6,7-tri-hydroxy-
2,3,4-tri-benzyloxy-9-[(1%S)-5,5-dimethyl-2,4-dioxolane-
1%-yl]}decalin 9
1
7.42%. [h]D=+35.8; H NMR l: 4.14 (m, H-1%), 4.04
(dd, J1%,2% 5.7, J2%,2%a 8.4, H-2%), 3.97 (d, J1,OH 7.8, OH),
3.89 (dd, J4,5 9.9, J3,4 10.2, H-4), 3.67 (m, H-1,2), 3.58
(m, H-3,2%a), 3.42 (dd, J5,6 5.1, J6,7 4.0, H-6), 3.34 (m,
H-7), 2.27 (m, H-5), 2.09 (m, H-8), 1.81 (m, H-9,10),
1.46 (m, H-8a), 1.39 and 1.35 [C(CH3)2]; 13C NMR l:
109.2 [C(CH3)2], 86.5, 81.5 (double intensity), 79.9, and
77.8 (C-1,2,3,4,1%), 67.9 (C-2%), 53.3 and 53.2 (C-6,7),
Olefin 7 (155 mg, 0.26 mmol) was dissolved in THF (5
mL), tert-butanol (0.2 mL) and water (0.05 mL) to
which N-methyl morpholine N-oxide (80 mg) and
osmium tetraoxide (0.2 mL of a ca. 2% solution in
toluene) were added. The mixture was stirred for 24 h

S. Jarosz, S. Sko´ra / Tetrahedron: Asymmetry 12 (2001) 1651–1656
1655
42.4, 38.0 and 32.9 (C-5,9,10), 28.3 (C-8), 26.4 and 25.8
[C(CH3)2]. NOE: H5-H6 (8.3%).
3.44 (dd, J4,5<1, H-4), 2.87 (d, J9,10 2.5, H-10), 2.61 (s,
H-5), 1.97 (m, H-8), 1.96 (CH3CO2), 1.75 (m, H-9), 1.32
and 1.29 [C(CH3)2], 1.11 (m, H-8a); 13C NMR l: 169.7
(CꢀO), 109.3 [C(CH3)2], 81.9 (C-4), 81.5 (C-2), 80.5
(C-3), 79.7 (C-2), 77.6 (C-6), 76.5 (C-1%), 73.0, 71.6 and
71.0 (3×CH2Ph), 71.2 (C-7), 68.8 (C-2%), 40.1 (C-9), 37.4
(C-5), 34.3 (C-10), 27.0 and 25.8 [C(CH3)2], 25.6 (C-8),
21.2 (CH3CO2). The strong 1H–1H correlations between
H-7 (at l=4.77 ppm) and both H-8 (1.97 and 1.11
ppm) were observed in the COSY spectrum.
4.4.2. Reaction of 8 with m-chloroperbenzoic acid. This
reaction was performed using the same procedure as
used to prepare 7. This afforded two products: 14 (52%)
and 15 (27%).
4.4.2.1. (1R,2S,3S,4R,5R,6S,7R,9S,10R)-{6,7-Anhy-
dro-1,2,3,4-tetra-benzyloxy-9-[(1%S)-5,5-dimethyl-2,4-
dioxolane-1%-yl]}decalin 14. HRMS m/z: 699.3312
[C43H48O7Na (M+Na+) requires 699.3292]. Anal. calcd
for C43H48O7: C, 76.31; H, 7.15. Found: C, 76.34; H,
4.6. Epoxide ring opening reactions with azide
1
7.24. [h]D=+70.5; H NMR l: 4.71 (m, H-1%), 3.81 (dd,
4.6.1. (1R,2S,3S,4R,5R,6S,7S,9S,10R)-{7-Azido-6-acet-
oxy-1,2,3,4-tetra-benzyloxy-9-[(1%S)-5,5-dimethyl-2,4-
dioxolane-1%-yl]}decalin 16-Ac. Epoxide 15 (180 mg, 0.26
mmol) was dissolved in ethanol (15 mL), water (4 mL)
and THF (4 mL). Sodium azide (120 mg, 1.8 mmol)
and ammonium chloride (120 mg) were added, the
mixture was heated under reflux for 24 h, cooled to rt
and partitioned between brine and ethyl acetate. The
organic layer was separated, washed with water, dried
and concentrated, the crude product was acetylated
under standard conditions and purified by column
chromatography (hexane:ethyl acetate, 6:1) to afford
16-Ac (180 mg, 89%) as an oil. HRMS m/z: 784.3565
[C45H51N3O8Na (M+Na+) requires 784.3568]. Anal.
calcd for C45H51N3O8: C, 70.94; H, 6.75; N, 5.52.
J1,2=J2,3 9.0, H-2), 3.73–3.59 (m, H-3,4, both 2%), 3.39
(dd, J1,10 4.1, H-1), 3.24 (dd, J5,6 2.6, J6,7 3.6, H-6), 2.92
(dd, J7,8 3.8, H-7), 2.21 (ddd, J4,5 11.1, J5,10 4.2, H-5),
2.02 (m, H-8,9), 1.94 (ddd, J9,10 11.0, H-10), 1.73 (m,
H-8a), 1.40 and 1.21 [C(CH3)2]; 13C NMR l: 107.9
[C(CH3)2], 87.3, 83.2, 81.9, 78.9 and 75.5 (C-
1,2,3,4,5,1%), 75.6, 75.4, 75.1 and 74.1 (4×CH2Ph), 64.7
(C-2%), 53.8 and 51.6 (C-6,7), 39.0, 34.0 and 32.8 (C-
5,9,10), 25.9 and 24.1 [C(CH3)2], 22.6 (C-8).
4.4.2.2. (1R,2S,3S,4R,5R,6R,7S,9S,10R)-{6,7-Anhy-
dro-1,2,3,4-tetra-benzyloxy-9-[(1%S)-5,5-dimethyl-2,4-
dioxolane-1%-yl]}decalin 15. HRMS m/z: 699.3303
[C43H48O7Na (M+Na+) requires 699.3292]. Anal. calcd
for C43H48O7: C, 76.31; H, 7.15. Found: C, 76.36; H,
1
Found: C, 71.10; H, 6.74; N, 5.41%. [h]D=+34.2; H
1
7.05%. [h]D=+42.3; H NMR l: 4.66 (m, H-1%), 3.90
NMR l: 5.35 (t, J5,6=J6,7ꢀ3, H-6), 4.93–4.75 (m,
CH2Ph and C-1%), 4.11 (t, J3,4=J4,5 9.1, H-4), 3.84 (m,
H-2 and H-7), 3.78 (t, J1%,2%=J2%,2%a 7.8, H-2%), 5.62 (dd,
J1%,2%a 5.6, H-2%a), 3.52 (t, J2,3 8.6, H-3), 3.41 (dd, J1,2 9.1,
J1,10 3.4, H-1), 2.19 (m, H-8 and H-9), 2.02 (H-10 and
CH3CO2), 1.91 (m, H-5), 1.50 (m, H-8a), 1.43 and 1.28
[C(CH3)2].
(dd, J3,4=J4,5 10.2, H-4), 3.76 (dd, J1,2 10.2, J2,3 8.8,
H-2), 3.70 (dd, J1%,2% 7.1, J2%,2%a 8.9, H-2%), 3.56 (m, H-3,
2%a), 3.42 (dd, J1,10 4.4, H-1), 3.37 (m, H-6,7), 2.42 (m,
H-8), 2.15 (ddd, J5,6ꢀJ5,10 5.0 Hz, H-5), 1.98 (m, H-9),
1.60 (m, H-8a), 1.42 and 1.23 [C(CH3)2]; 13C NMR l:
107.9 [C(CH3)2], 86.7, 81.7, 81.4, 79.9 and 75.3 (C-
1,2,3,4,1%), 75.4, 75.3, 74.9 and 74.7 (4×CH2Ph), 64.8
(C-2%), 53.9 and 53.0 (C-6,7), 39.9, 38.4 and 31.6 (C-
5,9,10), 26.0 (C-8), 25.8 and 24.0 [C(CH3)2].
4.6.2. (1R,2S,3S,4R,5R,6S,7S,9S,10R)-{6-Azido-7-acet-
oxy-1,2,3,4-tetra-benzyloxy-9-[(1%S)-5,5-dimethyl-2,4-
dioxolane-1%-yl]}decalin 18-Ac. This compound was
obtained from 15 analogously as described above in
67% yield. HRMS m/z: 784.3566 [C45H51N3O8Na (M+
Na+) requires 784.3568]. Anal. calcd for C45H51N3O8:
C, 70.94; H, 6.75; N, 5.52. Found: C, 70.94; H, 6.72; N,
5.31%. [h]D=+10.7; 1H NMR l: 5.08 (broad signal,
H-7), 4.23 (t, J5,6=J6,7 5.5, H-6), 4.07 (t, J3,4=J4,5 8.2,
H-4), 3.91 (m, H-2 and H-2%), 3.69 (m, H-3), 3.65 and
3.57 (2×m, H-1 and H-2%a), 2.20 and 1.61 (2×m, both
H-8), 2.03 (m, H-5).
4.5. Attempts to isomerize epoxides with LDA
A solution of the epoxide: 10, 11, 14, or 15 (ca. 0.25
mmol) in THF (15 mL) was cooled to −78°C under an
argon atmosphere. LDA (6 equiv., of a 2 M solution in
THF/heptane) was added at −78°C, the mixture was
allowed to attain 0°C in 2 h, saturated ammonium
chloride was added and the product was extracted with
ethyl acetate. From reactions of 11, 14, and 15 only
starting materials were recovered in almost quantitative
yields. Only from reaction of 10 a new product 13 was
obtained. It was characterized as acetate (75% yield
from 10), which was purified by column chromatogra-
phy (hexane:ethyl acetate, 2:1“1:1).
4.7. Opening of the oxirane ring with sodium acetate
4.7.1. Reaction of epoxide 14. Compound 14 (210 mg,
0.3 mmol) was dissolved in DMF (5 mL) to which
sodium acetate (250 mg) and acetic acid (0.25 mL) were
added and the mixture was heated at 100°C for 20 h.
The mixture was partitioned between brine and ethyl
acetate, the organic phase was separated, washed with
water, dried and concentrated and the products were
isolated by column chromatography (hexane:ethyl acet-
ate, 4:1“3:1) to afford two monoalcohols which were
identified as 17 (152 mg, 66%) and 19 (38 mg, 17%).
4.5.1.
(1R,2S,3S,4R,5R,6R,7R,9S,10R)-{7-O-Acetyl-
1,6-anhydro-2,3,4-tri-benzyloxy-9-[(1%S)-5,5-dimethyl-
2,4-dioxolane-1%-yl]}decalin
13-Ac.
HRMS
m/z:
651.2943 [C38H44O8Na (M+Na+) requires 651.2928].
Anal. calcd for C38H44O8: C, 72.59; H, 7.05. Found: C,
72.55; H, 7.23%. [h]D=−11.7; 1H NMR l: 4.77 (m,
H-7), 4.15 (m, H-1%), 3.97 (d, J1,2 2.6, H-1), 3.93 (m,
H-6,2%), 3.59 (dd, J2,3=J3,4 4.5, H-3), 3.47 (m, H-2,2%a),

1656
S. Jarosz, S. Sko´ra / Tetrahedron: Asymmetry 12 (2001) 1651–1656
Each alcohol (17 or 19) was separately acetylated under
standard conditions to afford the same product, perac-
etate 20 (purified by column chromatography in hex-
ane:ethyl acetate, 6:1) in quantitative yield.
797.3149]; 13C NMR l: 170.6, 170.5, 170.1, 169.7 (dou-
ble) (5×CꢀO), 86.9, 79.5 77.8, 75.4, 71.1, 68.5, 67.3
(C-1,2,3,4,6,7,1%), 61.9 (C-8), 44.4, 36.5, 35.7 (C-5,9,10),
25.9 (C-8), 21.2, 21.0, 20.8, 20.7, 20.6 (5×CH3CO2).
Compound 21 (140 mg, 0.18 mmol) was dissolved in ethyl
acetate (15 mL) and ethanol (5 mL) to which a few drops
of acetic acid were added. The mixture was subjected to
hydrogenation over 10% Pd/C for 12 h, filtered, concen-
trated and the residue was acetylated under standard
conditions. The crude product was purified by column
chromatography (hexane:ethyl acetate, 1:1) to afford the
desired octaacetate 22 in 90% yield; [h]D=+10.3; HRMS
[LSIMS] m/z: 653.2050 [C28H38O16Na (M+Na+) requires
653.2058]; Anal. calcd for C28H38O16: C, 53.33; H, 6.07.
4.7.1.1. (1R,2S,3S,4R,5R,6S,7S,9S,10R)-{6-Acetoxy-
7-hydroxy-2,3,4-tetra-benzyloxy-9-[(1%S)-5,5-dimethyl-
2,4-dioxolane-1%-yl]}decalin 17. 1H NMR l: 4.90 (m,
H-7), 4.22 (m, H-6), 4.04 (t, J3,4=J4,5 8.4, H-4), 3.88 (m,
H-2%), 3.83 (dd, J1,2 6.8 J2,3 7.3 H-2), 3.67 (m, H-3),
3.59–3.55 (m, H-2%a and H-1), 2.06 (CH3CO2), 2.00 (M,
H-5,8,10), 1.62 (m, H-8a), 1.38 and 1.28 [C(CH3)2].
4.7.1.2. (1R,2S,3S,4R,5R,6S,7S,9S,10R)-{7-Acetoxy-
6-hydroxy-2,3,4-tetra-benzyloxy-9-[(1%S)-5,5-dimethyl-
2,4-dioxolane-1%-yl]}decalin 19. 1H NMR l: 5.31 (t,
1
Found: C, 53.50; H, 6.23; H NMR l: 5.76 (m, H-1%),
5.62 (dd, J1,2 10.6, J2,3 9.2, H-2), 5.33 (dd, J3,4 9.1, J4,5
11.9, H-4), 5.25 (t, J5,6=J6,7 2.8, H-6), 5.08 (t, H-3), 5.06
(dd, J1,10 4.6, H-1), 4.99 (ddd, J7,8 4.4, J7,8a 11.9, H-7),
4.22 (dd, J1%,2% 8.4, J2%,2%a 12.1, H-2%), 4.12 (dd, J1%,2%a 2.7,
H-2%a), 2.41 (m, H-9 and H-10), 2.25 (ddd, J5,10 3.4, H-5),
2.13, 2.13, 2.10, 2.05, 2.03, 2.00, 1.99 and 1.97 (8×
CH3CO2), 2.05 and 1.60 (2×m, both H-8); 13C NMR l:
170.5, 170.4, 169.9, 169.8, 169.7, 169.6, 169.5 and 169.2
(8×CꢀO), 73.9 (C-3), 72.6 (C-1), 71.0 (C-1%), 69.2 (C-2),
68.2 (C-4), 68.1 (C-7), 66.8 (C-6), 61.9 (C-2%), 42.4 (C-5),
35.8 (C-10), 35.5 (C-9), 25.9 (C-8), 21.0 (double), 20.8,
20.7, 20.6, 20.5, 20.4 (double) (8×CH3CO2).
J
J
5,6=J6,7 3.2, H-6), 4.19 (H-4), 3.91 (H-7), 3.86 (t,
1,2=J2,3 8.9, H-2), 3.77 (H-2%a), 3.61 (dd, J1%,2% 6.0, J2%,2%a
8.4, H-2%), 3.52 (dd, J3,4 8.6, H-3), 3.45 (m, H-1), 2.30 (m,
H-9), 2.01 (H-8 and CH3CO2), 1.88 (m, H-5), 1.44 (m,
H-8a), 1.40 and 1.27 [C(CH3)2].
4.7.1.3. (1R,2S,3S,4R,5R,6S,7S,9S,10R)-{6,7-Di-acet-
oxy-2,3,4-tetra-benzyloxy-9-[(1%S)-5,5-dimethyl-2,4-diox-
olane-1%-yl]}decalin 20. HRMS (ESI) m/z: 801.3626
[C47H54O10Na (M+Na+) requires 801.3609]. Anal. calcd
for C47H54O10: C, 72.37; H, 6.99. Found: C, 72.40; H,
1
7.15%. [h]D=17.9; H NMR l: 5.42 (m, H-6), 5.05 (m,
H-7), 4.82 (m, H-1%), 4.03 (dd, J4,5 10.3, J3,4 8.8, H-4), 3.86
(t, J1,2=J2,3 9.3, H-2), 3.79 (t, J1%,2%=J2%,2%a 8.5, H-2%), 3.63
(dd, J1%,2%a 5.7, H-2%a), 3.54 (dd, H-3), 3.43 (dd, J1,10 3.8,
H-1), 2.18 (m, H-8,10), 2.05 and 2.03 (2×CH3CO2 and
H-9), 1.96 (m, H-5), 1.46 (m, H-8a), 1.39 and 1.27
[C(CH3)2].
Acknowledgements
This work was supported by Grant 3T09A 07015 from
the Polish State Committee for Scientific Research, which
is gratefully acknowledged.
4.7.2. Reaction of epoxide 16. Epoxide 16 was treated with
NaOAc and HOAc at 100°C for 4 h, as described in
Section 4.7.1 to afford a mixture of 17 and 19 in the ratio
ꢀ1:1, which upon acetylation afforded 79% of diacetate
20 identical in all respect with the diacetate obtained from
14.
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acetoxy-9-C-(1%,2%-diacetoxy-1%-ethyl)decalin 22
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