Intramolecular cationic cyclization of acetoxy derivatives of the levoglucosenone-cyclopentadiene endo-adduct

Article abstract of DOI:10.1134/S1070428015040193

Abstract Epoxidation of diastereoisomeric benzyloxy derivatives of the levoglucosenone adduct with cyclopentadiene by treatment with m-chloroperoxybenzoic acid afforded a mixture of 1,2- and 1,4-epoxy derivatives. Intramolecular cyclization of the hydroxy derivatives of the same adduct by the action of I₂-NaHCO₃-MeCN gave products resulting from cleavage of the 1,6-anhydro bridge, reduction of the acetal moiety, and olefinaldehyde cyclization.

Full text of DOI:10.1134/S1070428015040193

ISSN 1070-4280, Russian Journal of Organic Chemistry, 2015, Vol. 51, No. 4, pp. 576–581. © Pleiades Publishing, Ltd., 2015.
Original Russian Text © I.M. Biktagirov, L.Kh. Faizullina, Sh.M. Salikhov, M.M. Iskakova, M.G. Safarov, F.Z. Galin, F.A. Valeev, 2015, published in
Zhurnal Organicheskoi Khimii, 2015, Vol. 51, No. 4, pp. 593–598.
Intramolecular Cationic Cyclization of Acetoxy Derivatives
of the Levoglucosenone–Cyclopentadiene endo-Adduct
I. M. Biktagirova, L. Kh. Faizullinab, Sh. M. Salikhovb, M. M. Iskakovaa, M. G. Safarova,
F. Z. Galina, and F. A. Valeevb
a Bashkir State University, ul. Zaki Validi 32, Ufa, 450076 Bashkortostan, Russia
b Institute of Organic Chemistry, Ufa Research Center, Russian Academy of Sciences,
pr. Oktyabrya 71, Ufa, 450054 Bashkortostan, Russia
e-mail: sinvmet@anrb.ru
Received December 5, 2014
Abstract—Epoxidation of diastereoisomeric benzyloxy derivatives of the levoglucosenone adduct with cyclo-
pentadiene by treatment with m-chloroperoxybenzoic acid afforded a mixture of 1,2- and 1,4-epoxy derivatives.
Intramolecular cyclization of the hydroxy derivatives of the same adduct by the action of I2–NaHCO3–MeCN
gave products resulting from cleavage of the 1,6-anhydro bridge, reduction of the acetal moiety, and olefin–
aldehyde cyclization.
DOI: 10.1134/S1070428015040193
As an alternative approach [1] to the synthesis of
iridoid skeleton, we have studied transformations of
Diels–Alder adduct 1 derived from levoglucosenone
and cyclopentadiene [2]. The ability of the endo-R-hy-
droxy derivative of adduct 1 to undergo intramolecular
cyclization to 1,4-epoxide on treatment with m-chloro-
peroxybenzoic acid (m-CPBA) or I2–EtOH [2] allows
differentiation of substituents on the double bond. We
anticipated that the use in these reactions of protected
epimeric alcohols 2a and 2b should enable us to obtain
both 1,2-epoxides under analogous conditions.
hydride and benzyl chloride in DMSO, and the oxida-
tion of mixture 3a/3b with m-CPBA in chloroform
afforded a mixture of 1,2-epoxide 4 and 1,4-epoxide 5
(Scheme 1). Removal of the benzyl protection and
formation of epoxy bridge in R-epimer 3a are likely to
be favored by anchimeric assistance in intermediate
1,2-epoxide.
1,4-Epoxide 5 was subjected to Jones oxidation to
obtain ketone 6 which was converted into lactone 7
according to Baeyer–Villiger (Scheme 2). The func-
tional groups in 7 are differently susceptible to sub-
sequent transformations. Our attempts to obtain com-
pound 5 by hydrolysis of iodo derivative 8 [3] under
Benzyl ethers 3a and 3b were prepared by succes-
sive treatment of alcohols 2a and 2b with sodium
Scheme 1.
O
O
O
NaBH4, EtOH [2]
BzlCl, NaH, DMSO
O
O
O
O
OH
OBzl
3a, 3b, 98%
1
2a, 2b, 82%
O
O
O
O
m-CPBA, CHCl3
OBzl
+
O
O
HO
5, 45%
4, 32%
576

INTRAMOLECULAR CATIONIC CYCLIZATION OF ACETOXY DERIVATIVES
577
Scheme 2.
O
O
H2O2, AcOH
or m-CPBA, AcOH
O
O
Jones reagent, Me2CO
5
O
O
O
O
O
6
7
Scheme 3.
OH
OH
O
O
O
O
I2, NaHCO3, Et2O
I2, NaHCO3, MeCN
2a, 2b
8
+
+
O
O
O
I
8, 26%
9, 11%
10, 15%
different conditions were unsuccessful, and complex
mixtures of products were formed. We examined the
reaction of 2a/2b with iodine in acetonitrile and diethyl
ether–water (5:1), i.e., in solvents other than those
used in [2] (Scheme 3).
particular SnCl4 [4] which was successfully used in the
O-glycosylation of carbohydrates [5]. By treatment of
11a/11b with SnCl4 in MeOH–CH2Cl2 we obtained
compound 10 in 91% yield, regardless of the initial
diastereoisomer ratio (Scheme 4). These findings sug-
gest intermediacy of structure A in the cationic cy-
clization. In the presence of SnCl4 the major path is the
transformation of both diastereoisomers 11a and 11b
into product 10 through intermediate A (Scheme 5).
The reaction in Et2O–H2O followed the same iodo-
cyclization pattern as in EtOH, whereas in acetonitrile
1,4-epoxide 8, oxidation–reduction product 9, and
intramolecular cationic cyclization product 10 were
obtained together with unreacted S-epimer 2b. Cage
compound 10 is likely to result from intramolecular
Prins reaction which is known to be catalyzed by acids.
In fact, treatment of isomeric acetate mixture 11a/11b
with H3PO4 afforded 24% of 10. More appropriate
catalysts for such Prins reactions are metal halides, in
EXPERIMENTAL
1
The H and 13C NMR spectra were recorded on
a Bruker AM-300 spectrometer at 300 and 75.47 MHz,
respectively, as well as on a Bruker Avance III spec-
trometer at 500 MHz; CDCl3 was used as solvent
unless otherwise stated. The mass spectra were
obtained on a Hewlett Packard HP 5973 mass-selective
detector coupled with an HP 6890 gas chromatograph.
Sorbfil PTSKh-AF-A plates (Sorbpolimer, Krasnodar)
were used for analytical TLC. The melting points were
measured on a Boetius PHMK 05 melting point ap-
paratus. The elemental compositions were determined
on a Euro 2000 CHNS(O) analyzer. The optical
rotations were measured on a Perkin Elmer-341
polarimeter.
Scheme 4.
O
Ac2O
pyridine
SnCl4, MeOH
CH2Cl2
O
2a, 2b
10
90%
91%
OAc
11a, 11b (1:1)
Scheme 5.
O
SnCl3
(1S,2S,3R,6S,7R,9R)-10,12-Dioxatetracyclo-
[7 . 2 . 1 . 1 3 , 6 . 0 2 , 7 ]t r i d e c - 4 - e n - 8 - o n e (1 ) a n d
(1S,2S,3R,6S,7R,8RS,9R)-10,12-dioxatetracyclo-
[7.2.1.13,6.02,7]tridec-4-en-8-ol (2a/2b) were synthe-
sized according to the procedure described in [2].
O
11a, 11b
10
OAc
(1S,2S,3R,6S,7R,8RS,9R)-8-Benzyloxy-10,12-di-
A
oxatetracyclo[7.2.1.13,6.02,7]tridec-4-ene (3a/3b).
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 4 2015

BIKTAGIROV et al.
578
A solution of 0.06 g (2.70 mmol) of sodium hydride in
2.3 mL of dimethyl sulfoxide was stirred for 30 min
under argon, a solution of 0.35 g (1.80 mmol) of
epimer mixture 2a/2b in 3.0 mL of DMSO was added,
the mixture was stirred for 5 min, 0.34 g (2.7 mmol) of
benzyl chloride was added dropwise, and the mixture
was stirred at room temperature until the initial alco-
hols disappeared (TLC). The mixture was treated with
5.0 mL of water and extracted with ethyl acetate
(3×5.0 mL), the extract was dried over MgSO4, the
solvent was distilled off, and the residue was purified
by silica gel chromatography. Yield of 3a/3b 0.50 g
(98%), epimer ratio 1:1; oily material, Rf 0.4 (petro-
leum ether–EtOAc, 3:1).
oxapentacyclo[9.2.1.02,6.03,10.04,8]tetradecan-7-ol (5).
m-Chloroperoxybenzoic acid, 2.76 g (16.0 mmol), was
added to a solution of 1.18 g (4.0 mmol) of epimeric
benzyl ethers 3a/3b in 20.0 mL of chloroform, and the
mixture was stirred at room temperature until the
initial compounds disappeared (TLC). The mixture
was treated with 20 mL of water, the organic phase
was separated, and the aqueous phase was extracted
with chloroform (3×30 mL). The extracts were com-
bined with the organic phase, washed with a saturated
aqueous solution of NaHCO3 and brine, and dried over
MgSO4, the solvent was distilled off, and the residue
was subjected to silica gel chromatography to isolate
0.3 g (32%) of 4 and 0.3 g (45%) of 5.
(8R)-Epimer 3a. 1H NMR spectrum, δ, ppm: 1.20 d
Compound 4. Oily material, Rf 0.5 (petroleum
ether–EtOAc, 2:1), [α]D20 = –8° (c = 0.26, CHCl3). IR
spectrum, ν, cm–1: 3447, 2959, 1721, 1096, 847, 740,
(1H, 13-HB, 2J = 8.0 Hz), 1.31 d.t (1H, 13-HA, 2J = 8.0,
3
3J13A, 3 = 1.8, J13A, 6 = 1.8 Hz), 2.03 d.d (1H, 2-H,
1
3
3
3J2,7 = 9.7, J2,3 = 3.4 Hz), 2.76 d.d.d (1H, 7-H, J7, 2
=
700, 442. H NMR spectrum, δ, ppm: 0.70 d (1H,
2
2
3
3
13-HB, J = 10.0 Hz), 1.40 d.t (1H, 13-HA, J = 10.0,
9.7, J7, 6 = J7, 8 = 3.8 Hz), 2.90 m (1H, 3-H), 2.92 m
3J13A,3 = J13B,6 = 1.7 Hz), 2.08 d.d (1H, 2-H, J2,7
=
3
3
3
3
(1H, 6-H), 2.97 d.d (1H, 8-H, J8, 7 = 3.8, J8, 9
=
3
3
3.0 Hz), 3.67 d (1H, 11-HB, 2J = 6.7 Hz), 3.71 d.d (1H,
10.2, J2,3 = 3.8 Hz), 2.28 quint (1H, 7-H, J7,2 = 10.2,
3
3J7,6 = J7,8 = 3.3 Hz), 2.50 m (1H, 6-H), 2.60 m (1H,
2
3
11-HA , J = 6.7, J11A,1 = 4.4 Hz), 4.33 d (1H, 1-H,
3
3J1, 11A = 4.4 Hz), 4.62 d (2H, 1′-H, J = 12.9 Hz),
2
4-H), 3.10 d (1H, 5-H, J5,4 = 3.10 Hz), 3.37 d (1H,
3
3
3
3
4-H, J4,5 = 3.10 Hz), 3.46 t (1H, 8-H, J8,9 = J8,7
=
5.27 d (1H, 9-H, J9,8 = 3.0 Hz), 6.12 d.d (1H, 5-H,
3.3 Hz), 3.80 d (1H, 11-HB, 2J = 6.7 Hz), 3.82 d.d (1H,
3
3
3J5,6 = 5.5, J5,4 = 3.0 Hz), 6.30 d.d (1H, 4-H, J4,3
=
2
3
5.5, J4,5 = 3.0 Hz), 7.35 m (5H, Ph). 13C NMR spec-
trum, δC, ppm: 37.86 (C2), 41.10 (C7), 46.64 (C6),
47.39 (C3), 48.83 (C13), 70.33 (C11), 72.25 (C1′), 74.64
(C1), 74.44 (C8), 99.85 (C9); 127.27, 127.60, 128.11,
138.05 (Ph); 135.36 (C5), 138.65 (C4).
3
11-HA, J = 6.7, J11A,1 = 4.1 Hz), 4.55 d (1H, 1-H,
3J1,11A = 4.1 Hz), 4.68 s (2H, 1′-H), 5.40 d (1H, 9-H,
3J9,8 = 3.3 Hz), 7.38 m (5H, Ph). 13C NMR spectrum,
δC, ppm: 27.06 (C13), 39.62 (C6), 39.80 (C3), 42.04
(C7), 44.49 (C2), 49.65 (C5), 50.10 (C4), 71.16 (C1′),
71.79 (C1), 73.71 (C8), 98.32 (C9); 128.05, 128.59,
129.85, 137.84 (Ph). Mass spectrum: m/z 301 [M – H]+.
Found, %: C 71.95; H 6.68. C18H20O4. Calculated, %:
C 71.92; H 6.66. M 300.349.
(8S)-Epimer 3b. 1H NMR spectrum, δ, ppm: 1.35 d
(1H, 13-HB, 2J = 8.2 Hz), 1.40 d.t (1H, 13-HA, 2J = 8.2,
3
3
3J13A,3 = J13A,6 = 1.8 Hz), 2.27 d.d (1H, 2-H, J2,7
=
=
10.0, 3J2,3 = 3.2 Hz), 2.43 d.d.d (1H, 7-H, 3J7,2 = 3J7,8
3
Compound 5. Colorless crystals, mp 118°C, Rf 0.3
(petroleum ether–EtOAc, 2:1), [α]D20 = –13° (c = 0.16,
CHCl3). 1H NMR spectrum, δ, ppm: 1.35 d (1H, 5-HB,
10.0, J7,6 = 4.4 Hz), 2.86 m (1H, 3-H), 3.10 m (1H,
6-H), 3.55 d.d (1H, 8-H, 3J8,7 = 10.0 Hz), 3.60 d.d (1H,
2
3
11-HA, J = 6.6, J11A,1 = 4.7 Hz), 3.84 d (1H, 11-HB,
3
3
2J = 10.6 Hz), 1.66 d.d (1H, 2-H, J2,3 = 10.0, J2,6
=
2J = 6.6 Hz), 4.32 d (1H, 13-H, 3J1,11A = 4.7 Hz), 4.64 d
2
3.2 Hz), 2.00 d (1H, 5-HA, J = 10.6 Hz), 2.21 m (1H,
6-H), 2.47 quint (1H, 3-H, J3,2 = 10.0, J3,4 = J3,10
5.0 Hz), 2.77 t (1H, 4-H, J4, 3 = J4, 8 = 5.0 Hz),
3.78 d.d (1H, 13-HA, J = 6.8, J13A,1 = 5.0 Hz), 3.81 d
2
(2H, 1′-H, J = 12.9 Hz), 5.20 s (1H, 9-H), 5.98 d.d
3
3
3
=
(1H, 5-H, 3J5,6 = 5.8, 3J5,4 = 3.0 Hz), 6.23 d.d (1H, 4-H,
3
3
3J4,3 = 5.8, J4,5 = 3.0 Hz), 7.35 m (5H, Ph). 13C NMR
3
2
3
spectrum, δC, ppm: 37.88 (C2), 41.16 (C7), 46.76 (C6),
47.53 (C3), 50.23 (C13), 70.84 (C11), 71.24 (C1′), 74.14
(C1), 76.02 (C8), 98.25 (C9); 127.27, 127.60, 128.11,
138.05 (Ph); 130.21 (C5), 135.66 (C4). Mass spectrum:
m/z 285.0 [M – H]+. Found, %: C 75.99; H 7.01.
C18H20O3. Calculated, %: C 75.96; H 7.03. M 284.3496.
2
3
(1H, 13-HB, J = 6.8 Hz), 3.83 d.d (1H, 10-H, J10,3
=
5.0, 3J10,11 = 2.1 Hz), 4.09 d (1H, 1-H, 3J1,13A = 5.0 Hz),
3
4.58 s (1H, 7-H), 4.61 d (1H, 8-H, J8, 4 = 5.0 Hz),
5.35 d (1H, 11-H, 3J11,10 = 2.1 Hz). 13C NMR spectrum,
δC, ppm: 32.52 (C5), 33.97 (C3), 40.52 (C2), 44.78 (C6),
46.87 (C4), 68.83 (C13), 73.71 (C7), 75.03 (C1), 76.88
(C10), 89.17 (C8), 99.21 (C11). Mass spectrum: m/z 211
[M – H]+. Found, %: C 62.77; H 6.68. C11H14O4. Cal-
culated, %: C 62.79; H 6.66. M 210.2265.
(1S,2S,3S,4S,5R,6R,7R,8R,9R)-8-Benzyloxy-4,5-
epoxy-10,12-dioxatetracyclo[7.2.1.13,6.02,7]tridecane
(4) and (1S,2S,3R,4R,6S,7S,8S,10R,11R)-9,12,14-tri-
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 4 2015

INTRAMOLECULAR CATIONIC CYCLIZATION OF ACETOXY DERIVATIVES
579
1
2929, 2852, 1730, 1460, 1101, 1035, 418. H NMR
(1S,2R,3R,4R,6S,8S,10R,11R)-9,12,14-Trioxa-
pentacyclo[9.2.1.02,6.03,10.04,8]tetradecan-7-one (6).
A solution of 0.61 g (2.90 mmol) of alcohol 5 in 20 mL
of acetone was cooled to –15°C, 1.1 mL of Jones’
reagent was added dropwise under vigorous stirring,
and the mixture was stirred for 15 min (TLC). The
mixture was then treated with 10 mL of propan-2-ol,
filtered, treated with a saturated aqueous solution of
NaHCO3, and extracted with ethyl acetate (3×30 mL).
The extract was washed with saturated aqueous solu-
tions of NaHCO3 and NaCl and dried over MgSO4, the
solvent was distilled off, and the residue was purified
by silica gel chromatography. Yield 0.55 g (91%),
spectrum, δ, ppm: 1.79 d.t (1H, 5-HB, 2J = 12.7, 3J5B,6
=
3J5B,4 4.1 Hz), 2.05 d (1H, 5-HA, 2J = 12.7 Hz), 2.23 d.d
(1H, 2-H, 3J2,3 = 9.8, 3J2,6 = 6.0 Hz), 2.97 d.t (1H, 3-H,
3J3,2 = 9.8, J3,4 = J3,11 = 7.4 Hz), 3.05 m (2H, 4-H,
3
3
2
6-H), 3.83 d (1H, 14-HB, J = 7.2 Hz), 3.90 d.d (1H,
2
3
14-HA, J = 7.2, J14A,1 = 5.3 Hz), 4.14 d (1H, 11-H,
3J11, 3 = 7.4 Hz), 4.71 d (1H, 1-H, J1, 14A = 5.3 Hz),
3
3
5.44 s (1H, 12-H), 5.79 d (1H, 9-H, J9,4 = 5.4 Hz).
13C NMR spectrum, δC, ppm: 32.66 (C5), 38.63 (C4),
43.17 (C6), 50.57 (C2), 51.81 (C3), 69.99 (C14), 73.95
(C1), 76.16 (C11), 101.38 (C12), 108.71 (C9), 176.30
(C7). Mass spectrum: m/z 225 [M – H]+. Found, %:
C 58.85; H 5.37. C11H12O5. Calculated, %: C 58.87;
H 5.35. M 224.21.
colorless crystals, mp 138°C, Rf10.6 (EtOAc), [α]D20
=
+21.2° (c = 0.35, DMSO). H NMR spectrum
2
(DMSO-d6), δ, ppm: 1.62 d.t (1H, 5-HB, J = 11.2,
(1S,2R,3R,4R,6S,7S,8S,10R,11R)-7-Iodo-9,12,14-
trioxapentacyclo[9.2.1.02,6.03,10.04,8]tetradecane (8).
A solution of 0.50 g (1.60 mmol) of epimer mixture
2a/2b in a mixture of 15.0 mL of diethyl ether and
3.0 mL of water was cooled to 0°C, 0.27 g (3.20 mmol)
of NaHCO3 and 0.81 g (3.20 mmol) of I2 were added,
and the mixture was allowed to warm up to room
temperature and stirred until the initial compounds
disappeared (TLC). The mixture was then extracted
with ethyl acetate (3×5 mL), the organic extract was
washed with an aqueous solution of Na2S2O3 and with
water and dried over MgSO4, the solvent was distilled
off, and the residue was purified by silica gel chroma-
tography. Yield 0.57 g (64%), colorless crystals,
mp 128°C, Rf 0.7 (petroleum ether–EtOAc, 1:1),
[α]D20 = +70.6° (c = 1.50, CHCl3). IR spectrum, ν, cm–1:
3
2
3J5B,6 = J5B,4 = 1.3 Hz), 1.70 d.t (1H, 5-HA, J = 11.2,
3J5A,6 = 1.5, J5A,4 = 1.3 Hz), 2.10 d.d (1H, 2-H, J2,3
9.6, J2,6 = 3.3 Hz), 2.43 m (1H, 7-H), 2.80 d.t (1H,
3-H, J3,2 = 9.6, J3,10 = J3,4 = 5.6 Hz), 2.93 t.d (1H,
4-H, J4,3 = 5.6, J4,8 = 5.4, J4,5B = 1.5, J4,5A = 1.3 Hz),
=
3
3
3
3
3
3
3
3
3
3
2
3
3.68 d.d (1H, 13-HA, J = 7.2, J13A,1 = 5.4 Hz), 3.81 d
2
3
(1H, 13-HB, J = 7.2 Hz), 4.53 d (1H, 8-H, J8,4
=
5.4 Hz), 5.24 d (1H, 11-H, J11,10 = 2.2 Hz). 13C NMR
spectrum (DMSO-d6), δC, ppm: 28.75 (C5), 33.64 (C3),
39.93 (C4), 40.83 (C2), 48.64 (C6), 67.27 (C13), 72.12
(C1), 76.55 (C10), 80.69 (C8), 98.93 (C11), 211.41 (C7).
Found, %: C 63.38; H 5.70. C11H12O4. Calculated, %:
C 63.40; H 5.76.
3
(1S,2R,3S,4R,6S,9R,11R,12R)-8,10,13,15-Tetra-
oxapentacyclo[10.2.1.02,6.03,11.04,9]pentadecan-7-one
(7). a. m-Chloroperoxybenzoic acid, 0.62 g, was added
to a solution of 0.015 g (0.07 mmol) of ketone 6 in
2.0 mL of glacial acetic acid, and the mixture was
stirred for 24 h (TLC). The mixture was treated with
water and extracted with chloroform (3×5 mL), the
extract was washed with an aqueous solution of
Na2S2O3 and dried over MgSO4, the solvent was
distilled off, and the residue was subjected to silica gel
chromatography. Yield 0.05 g (20%).
1
1350, 1340, 1035, 966, 956, 721, 690. H NMR spec-
3
trum (C6D6), δ, ppm: 0.76 d.d (1H, 2-H, J2,6 = 2.3,
3J2,3 = 9.6 Hz), 1.05 d (1H, 5-HA, J = 10.7 Hz),
2
3
3
3
1.81 d.d.d.d (1H, 3-H, J3,4 = 4.9, J3,10 = 5.4, J3,2
9.6 Hz), 2.06 d (1H, 5-HB, J = 10.7 Hz), 2.11 m (1H,
6-H), 2.19 m (1H, 4-H), 3.12 d (1H, 13-HA, J =
=
2
2
3
2
6.8 Hz), 3.42 d.d (1H, 13-HB3, J13B,1 = 5.3, J =
3
6.8 Hz), 3.66 d.d (1H, 10-H, J10,11 = 1.6, J10,3
=
3
5.4 Hz), 3.77 d (1H, 1-H, J1,13B = 5.3 Hz), 4.91 d (1H,
8-H, J8,4 = 4.8 Hz), 5.10 d (1H, 7-H, J7,6 = 2.2 Hz),
3
3
b. Ketone 6, 0.25 g (1.2 mmol), was dissolved in
7.0 mL of glacial acetic acid, 2.5 mL of a 35% solution
of hydrogen peroxide was added, and the mixture was
stirred until initial ketone 6 disappeared (TLC). The
mixture was treated with water, 1 g of NaHCO3 was
added, and the mixture was extracted with chloroform
(3×30 mL). The extract was dried over MgSO4, the
solvent was distilled off, and the residue was purified
by silica gel chromatography. Yield 0.01 g (63%),
3
13
5.40 d (1H, 11-H, J11,10 = 1.6 Hz). C NMR spectrum
(C6D6), δC, ppm: 33.52 (C7), 33.56 (C3), 37.17 (C5),
47.11 (C2), 47.93 (C6), 48.80 (C4), 68.49 (C13), 73.18
(C1), 76.61 (C10), 91.12 (C8), 99.31 (C11). Mass
spectrum: m/z 320 [M – H]+. Found, %: C 41.20;
H 4.09. C11H13IO3. Calculated, %: C 41.23; H 4.06.
M 320.1236.
(1R,2S,3S,7R,8S)-3-(Hydroxymethyl)-4-oxa-
tricyclo[6.2.1.02,7]undec-9-en-6-one (9) and
{(1S,2R,3R,5S,6R,8S,9S,10S,12S)-4,12-dioxapenta-
colorless crystals, mp 145°C, Rf 0.3 (EtOAc), [α]D20
–3.9° (c = 1.65, MeOH). IR spectrum, ν, cm–1: 2951,
=
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BIKTAGIROV et al.
580
cyclo[6.4.0.02,6.03,10.05,9]dodec-11-yl}methanol (10).
A solution of 1.0 g (5.20 mmol) of 2a/2b in 35.0 mL of
acetonitrile was cooled to 0°C, 0.87 g (10.40 mmol) of
NaHCO3 and 2.65 g (10.40 mmol) of I2 were added,
and the mixture was stirred for 1 h at room temperature
(TLC). The mixture was treated with 10 mL of water
and extracted with ethyl acetate (3×40 mL), The ex-
tract was washed with an aqueous solution of Na2S2O3
and with water and dried over MgSO4; the solvent was
distilled off, and the residue was subjected to silica gel
chromatography to isolate 0.34 g (26%) of iodide 8,
0.11 g (11%) of hydroxy ketone 9, and 0.13 g (15%) of
compound 10.
C 67.91; H 7.22. C11H14O3. Calculated, %: C 67.96;
H 7.21.
(1S,2S,3R,6S,7R,8RS,9R)-10,12-Dioxatetracyclo-
[7.2.1.13,6.02,7]tridec-4-en-8-yl acetate (11a/11b).
Acetic anhydride, 0.25 mL (2.30 mmol), was added to
a solution of 0.30 g (1.60 mmol) of epimeric alcohols
2a/2b in 7.0 mL of anhydrous pyridine, and the mix-
ture was stirred until the initial compounds disap-
peared (TLC). The mixture was then treated with 5 mL
of water and 3 mL of a saturated aqueous solution of
NaHCO3 and extracted with ethyl acetate (3×20 mL).
The extract was washed with 5% aqueous HCl and
brine and dried over MgSO4, the solvent was distilled
off, and the residue was purified by silica gel chro-
matography. Yield 0.33 g (90%), epimer ratio 1:1; oily
material, Rf 0.5 (petroleum ether–EtOAc, 3:1).
Compound 9. Oily material, Rf 0.35 (petroleum
ether–EtOAc, 1:1), [α]D20 = –162.9° (c = 1.4, CHCl3).
1H NMR spectrum (C6D6), δ, ppm: 0.82 d and 1.21 d
2
(1H each, 11-H, J = 8.4 Hz), 2.26 d.d.d (1H, 2-H,
(R)-Epimer 11a. 1H NMR spectrum, δ, ppm: 1.18 d
3
3
3J2,7 = 3.1, J2,3 = J2,1 = 10.6 Hz), 2.33 d.d (1H, 7-H,
2
and 1.29 d (1H each, 13-H, J = 8.5 Hz), 2.07 s (3H,
3J7, 2 = 3.1, J7, 8 = 10.4 Hz), 2.36 m (1H, 1-H),
3
CH3), 2.28 m (1H, 2-H), 2.77 m (1H, 7-H), 2.90 m
2.61 d.d.d.d (1H, 3-H, 3J3,1′A = 2.8, J3,1′B = 6.8, J3,2
=
3
3
(1H, 3-H), 3.04 m (1H, 6-H), 3.70 d.d (1H, 8-H, 3J8,7
=
10.6 Hz), 3.21 m (1H, 8-H), 3.38 d.d (1H, 5-HA,
3
2
6.8, J8,9 = 3.0 Hz), 4.27 d.d (1H, 11-HB, J = 7.4,
3J5A,7 = 1.0, 2J = 18.0 Hz), 3.46 d.d (1H, 1′-HA, 3J1′A,3
=
2
3J11B, 1 = 4.4 Hz), 4.31 d (1H, 11-HA, J = 7.4 Hz),
2
3
2.8, J = 11.8 Hz), 3.77 d.d (1H, 1′-HB, J1′B,3 = 6.8,
3
4.38 d (1H, 1-H, J1,11B = 4.4 Hz), 5.17 d (1H, 9-H,
2J = 11.8 Hz), 3.95 d (1H, 5-HB, 2J = 18.0 Hz), 5.61 d.d
3J9,8 = 3.0 Hz), 6.12 m (1H, 5-H), 6.26 m (1H, 4-H).
13C NMR spectrum, δC, ppm: 20.98 (COCH3), 37.07
(C2), 41.08 (C7), 46.42 (C6), 47.71 (C3), 49.98 (C13),
69.39 (C1), 71.40 (C11), 72.33 (C8), 99.79 (C9), 136.13
(C5), 137.42 (C4), 170.01 (C=O).
3
3
(1H, 10-H, J10,9 = 2.6, J10,1 = 5.3 Hz), 6.15 d.d (1H,
9-H, J9,10 = 2.6, J9,8 = 5.3 Hz). 13C NMR spectrum
(C6D6), δC, ppm: 42.06 (C2), 44.16 (C1), 45.14 (C8),
48.47 (C11), 48.76 (C7), 64.89 (C1′), 73.66 (C5), 81.54
(C3), 134.51 (C10), 138.10 (C9), 210.68 (C6). Mass
spectrum: m/z 195 [M – H]+. Found, %: C 67.90;
H 7.22. C11H14O3. Calculated, %: C 67.96; H 7.21.
M 194.2271.
3
3
1
(S)-Epimer 11b. H NMR spectrum, δ, ppm: 1.20 d
2
and 1.38 d (1H each, 13-H, J = 8.5 Hz), 2.07 s (3H,
CH3), 2.28 m (1H, 2-H), 2.77 m (1H, 7-H), 2.80 m
(1H, 3-H), 2.87 m (1H, 6-H), 3.55 d.d (1H, 11-HB, 2J =
Compound 10. Oily material, Rf 0.2 (petroleum
ether–EtOAc, 1:1), [α]D20 = –147.0° (c = 1.45, CHCl3).
1H NMR spectrum (DMSO-d6), δ, ppm: 1.31 d (1H,
3
2
6.6, J11B,1 = 4.1 Hz), 3.68 d (1H, 11-HA, J = 6.6 Hz),
2
3.79 d (1H, 1-H, J1,11B = 4.1 Hz), 4.83 d (1H, 8-H,
3J8,7 = 9.8 Hz), 5.02 s (1H, 9-H), 6.12 m (1H, 5-H),
2
3
3
7-HB, J = 10.2, J7B,8 = J7B,6 = 1.5 Hz), 1.48 d (1H,
13
2
3
6.26 m (1H, 4-H). C NMR spectrum, δC, ppm: 21.06
7-HA, J = 10.2 Hz), 1.78 d.d.d.d (1H, 1-H, J1,8 = 6.5,
(COCH3), 37.07 (C2), 40.36 (C7), 46.71 (C5), 47.02
(C6), 49.12 (C13), 70.42 (C11), 74.21 (C1), 74.54 (C8),
97.61 (C9), 131.91 (C5), 135.60 (C4), 170.47 (C=O).
Found, %: C 66.11; H 6.78. C13H16O4. Calculated %:
C 66.09; H 6.83.
3J1,2 = 5.3, 3J1,11 = 3.0 Hz), 2.01 d.d.d (1H, 9-H, 3J9,5
=
3J9, 10 = 6.5, J9, 8 = 5.7 Hz), 2.07 m (1H, 8-H),
3
3
3
3
2.26 d.d.d (1H, 2-H, J2,1 = 6.5, J2,3 = J2,6 = 5.3 Hz),
2
2.42 m (1H, 6-H), 3.29 d.d.d.d (1H, 1′-HB, J = 11.0,
3J1′B,11 = 6.3, 3J1′B,OH = 5.6 Hz), 3.36 d.d.d.d (1H, 1′-HA,
2J = 11.0, 3J1′A,11 = 6.3, 3J1′A,OH = 5.6 Hz), 3.51 d.d (1H,
{(1S,2R,3R,5S,6R,8S,9S,10S,12S)-4,12-Dioxa-
pentacyclo[6.4.0.02,6.03,10.05,9]dodec-11-yl}methanol
(10). a. Epimer mixture 11a/11b, 0.12 g (0.48 mmol),
was dissolved in 5.0 mL of anhydrous methylene
chloride, 0.08 mL (0.72 mmol) of SnCl4 was added at
room temperature, and the mixture was stirred for
15 min. Methanol, 0.03 mL (0.72 mmol), was added
dropwise, and the mixture was stirred until the initial
compounds disappeared (TLC). The mixture was
3
3
10-H, J10, 9 = 6.5, J10, 3 = 3.0 Hz), 3.76 d.d.d (1H,
3
3
3
11-H, J11,1′B = J11,1′A = 6.3, J11,1 = 3.0 Hz), 4.25 d.d
3
3
(1H, 3-H, J3,2 = 5.3, J3,10 = 3.0 Hz), 4.57 d.d (1H,
3
3
5-H, J5, 9 = 6.5, J5, 6 = 3.5 Hz), 4.67 t (1H, OH,
3JOH, 1′A = JOH, 1′B = 5.6 Hz). 13C NMR spectrum
3
(C6D6), δC, ppm: 31.49 (C7), 35.32 (C2), 36.01 (C9),
38.51 (C8), 38.89 (C1), 48.39 (C6), 64.01 (C1′), 71.54
(C11), 73.59 (C10), 75.80 (C3), 86.09 (C5). Found, %:
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 4 2015

INTRAMOLECULAR CATIONIC CYCLIZATION OF ACETOXY DERIVATIVES
581
treated with 3.0 mL of a saturated aqueous solution
of NaHCO3 and extracted with methylene chloride
(3×7 mL). The extract was dried over MgSO4, the
solvent was distilled off, and the residue was purified
by silica gel chromatography. Yield 0.08 g (91%).
of Organic Chemistry, Ufa Research Center, Russian
Academy of Sciences).
This study was performed under financial support
by the Russian Foundation for Basic Research (project
no. 13-00-14056, 14-03-97007-r_povolzh’e_a).
b. Epimer mixture 11a/11b, 0.14 g (0.60 mmol),
was dissolved in 3.0 mL of 92% H3PO4, and the mix-
ture was stirred at 50°C until the initial compounds
disappeared (TLC). The mixture was cooled to room
temperature, treated with 1 mL of water and 3 mL of
a saturated aqueous solution of NaHCO3, and extracted
with ethyl acetate (3×5 mL). The extract was washed
with 5% aqueous HCl and brine and dried over
anhydrous magnesium sulfate, the solvent was distilled
off, and the residue was subjected to silica gel chroma-
tography. Yield 0.03 g (24%).
REFERENCES
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Salikhov, Sh.M., Safarov, M.G., and Valeev, F.A., Russ. J.
Org. Chem., 2014, vol. 50, p. 105.
2. Horton, D. and Bhate, P., Carbohydr. Res., 1983,
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3. Sharipov, B.T., Zagreeva, I.A., and Valeev, F.A., Butlerov.
Soobshch., 2011, vol. 25, p. 105.
4. Arundale, E. and Mikeska, L.A., Chem. Rev., 1952,
vol. 51, p. 505.
The NMR and IR spectra were recorded using the
5. Hanessian, S. and Banoub, J., Carbohydr. Res., 1977,
equipment of the Khimiya Shared Use Center (Institute
vol. 59, p. 261.
RUSSIAN JOURNAL OF ORGANIC CHEMISTRY Vol. 51 No. 4 2015