1,3-Dipolar cycloadditions of D-erythrose- and D-threose-derived alkenes with nitrones

Article abstract of DOI:10.1135/cccc20030951

The new chiral terminal alkenes derived from cyclic acetals of D-erythrose 1-3 and D-threose 5, 6 were prepared. The alkenes 1, 2 and 5 react with chiral nitrones to afford the corresponding diastereomeric isoxazolidines 19-21. The stereoselectivity was dependent on the steric hindrance of the nitrone. In all cases the cycloadditions are endo-selective. The major products were found to have the C-3/C-4 erythro- and C-3/C-3a cis-configuration. Its formation can be rationalized by a less hindered endo-attack of the (Z)-nitrone in an antiperiplanar manner with respect to the largest group of the cyclic acetal.

Full text of DOI:10.1135/cccc20030951

1,3-Dipolar Cycloadditions
951
1,3-DIPOLAR CYCLOADDITIONS OF D-ERYTHROSE- AND
D-THREOSE-DERIVED ALKENES WITH NITRONES
b
Iva BLANÁRIKOVÁ-HLOBILOVÁa1, Lubor FIŠERAa2,*, Naꢀa PRÓNAYOVÁ and
c
Marian KOMAN
a
Department of Organic Chemistry, Slovak University of Technology, SK-812 37 Bratislava,
1
2
Slovak Republic; e-mail: hlobil@hotmail.com, fisera@cvt.stuba.sk
Central Laboratory of Chemical Techniques, Slovak University of Technology,
SK-812 37 Bratislava, Slovak Republic; e-mail: pronayova@chtf.stuba.sk
Department of Inorganic Chemistry, Slovak University of Technology, SK-812 37 Bratislava,
Slovak Republic; e-mail: koman@cvt.stuba.sk
b
c
Received December 30, 2002
Accepted March 21, 2003
Dedicated to the memory of Professor Otakar Červinka.
The new chiral terminal alkenes derived from cyclic acetals of D-erythrose 1–3 and D-threose
5, 6 were prepared. The alkenes 1, 2 and 5 react with chiral nitrones to afford the corre-
sponding diastereomeric isoxazolidines 19–21. The stereoselectivity was dependent on the
steric hindrance of the nitrone. In all cases the cycloadditions are endo-selective. The major
products were found to have the C-3/C-4 erythro- and C-3/C-3a cis-configuration. Its forma-
tion can be rationalized by a less hindered endo-attack of the (Z)-nitrone in an antiperi-
planar manner with respect to the largest group of the cyclic acetal.
Keywords: Dipolar cycloadditions; Chiral nitrones; Isoxazolidines; Chiral alkenes;
Stereoselectivity; Carbohydrates; Polyols; Wittig reaction.
The nitrone–olefin 1,3-dipolar cycloaddition is a powerful reaction since it
can create as many as three new contiguous stereogenic centers in a single
step1. Based on an evaluation of the nitrone cycloaddition, it was felt that
the configuration of these new centers could be influenced if the reaction
system was properly designed2. Regio- and stereoselective nitrone cyclo-
addition, followed by reduction of the N–O bond to produce both an ami-
no and a hydroxy function, allows the synthesis of many products of
potential interest3. Over the years, nitrones have become important build-
ing blocks in organic synthesis1,4. With the goal of developing a simple
route to polyhydroxy derivatives of piperidine5 via an asymmetric 1,3-di-
polar cycloaddition, we have recently published the preparation of new
Collect. Czech. Chem. Commun. (Vol. 68) (2003)
doi:10.1135/cccc20030951

952
Blanáriková-Hlobilová et al.:
D-erythrose- and D-threose-derived nitrones 9 and 10 and the stereo-
selectivity of their cycloadditions to styrene and methyl acrylate6,7
.
In this paper we report in detail the preparation of new D-erythrose- and
D-threose-derived alkenes 1–3 and 5, 6 and the stereoselectivity of their
cycloaddition to achiral nitrone 7 and chiral saccharide-derived nitrones 8,
9 and 10 (Scheme 1).
OH
OTBDMS
OTBDPS
OTBDPS
OH
OTBDMS
O
O
O
O
O
O
O
O
O
O
O
O
4
5
3
1
6
2
OH
OH
Bn
Bn
N
O
N
O
N
O
O
O
O
O
O
O
MeOOC
N
O
Bn
Bn
7
8
9
10
SCHEME 1
The chiral alkene 1 was prepared in 31% yield by Wittig reaction of
2,4-O-ethylidene-D-erythrose (11)8, readily available from D-glucose, with
methylenetriphenylphosphorane, generated from methyltriphenylphos-
phonium bromide and butyllithium (Scheme 2). The chiral alkene 4 could
not be prepared by Wittig reaction from the D-threose derivative8 15 under
the same reaction conditions as for 1. In this case the reaction proceeded
only under the formation of unidentified compounds. Since the directly
silylation of alkene 1 was not successful, we have decided to overcome this
problem by the preparation of the corresponding hydrazone 12, with the
subsequent silylation, deprotection of the carbonyl group and smooth
Wittig reaction. Thus, the key step for the preparation of the D-erythrose-
(2 and 3) and D-threose-derived alkenes 5 and 6, consists in the protection
of the free hydroxy group on C-3 (Schemes 2 and 3). The alkenes 2 and 3
were synthesized starting from the D-erythrose derivative 11, which was
smoothly transformed via intermediate 12 into the corresponding pro-
tected hydrazones9 13 and 14 in 82 and 76% yield, respectively. The corre-
sponding alkenes 2 and 3 were obtained by degradation of hydrazones 13
and 14 with nitrous acid10 followed by Wittig reaction in yields of 48 and
58% in two steps (Scheme 2). Analogously, 2,4-O-ethylidene-D-threose (15),
readily available from D-galactose, was converted to the corresponding to
D-threose-derived alkenes 5 and 6 (Scheme 3).
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

1,3-Dipolar Cycloadditions
953
OH
OH
iii
i, ii
iv
O
D-glucose
O
O
O
O
11
1
OH
OR
OR
vi, vii
N
N
v
N
N
O
O
O
O
O
O
12
13, 14
2, 3
2, 13: R = TBDMS
3, 14: R = TBDPS
(i) paraldehyde, H2SO4, 3 d, r.t.; (ii) NaIO4, H2O, MeOH, 10 oC, 2 h; (iii) Ph3P+CH3Br-,
3 eq. BuLi, THF, 75 oC; (iv) NH2NMe2, MgSO4, MeOH, 3.5 h; (v) R-Cl, imidazole,
CH2Cl2, 24 h; (vi) NaNO2, AcOH, H2O, 4 h; (vii) Ph3P+CH3Br-, 2 eq. BuLi, THF, 0 oC - r.t.;
SCHEME 2
OH
OH
N
iii
i, ii
O
N
D-galactose
O
O
O
O
15
16
OR
OR
iv
N
v, vi
N
O
O
O
O
17, 18
5, 6
5, 17: R = TBDMS
6, 18: R = TBDPS
(i) paraldehyde, H2SO4, 3 d, r.t.; (ii) NaIO4, H2O, MeOH, 10 oC, 2 h; (iii) NH2NMe2, MgSO4, MeOH,
3.5 h; (iv) R-Cl, imidazole, CH2Cl2, 24 h; (v) NaNO2, AcOH, H2O, 4 h; (vi) Ph3P+CH3Br-,
2 eq. BuLi, THF, 0 oC - r.t.
SCHEME 3
The prepared chiral diastereomerically pure terminal alkenes 1, 2 and 5
were subjected to 1,3-dipolar cycloadditions. Our concern was to study the
asymmetric induction from the alkene part with achiral nitrone 7 and dou-
ble asymmetric induction in cycloaddition with chiral nitrones 8–10. The
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

954
Blanáriková-Hlobilová et al.:
regioselectivity of the cycloaddition was high; indeed 5-substituted
isoxazolidines were formed exclusively, 4-substituted isoxazolidines were
not detected in crude reaction mixtures by NMR spectra. There are four pos-
sible products; cis- and trans-isomers from anti- and syn-attack (Scheme 4).
O
O
OR
OR
O
O
O
N
O
N
+
O
O
Bn
Bn
OH
OR
O
O
O
OH
O
1, 2
+
19b
20b
19a
20a
+
O
O
O
OH
OR
O
OR
O
O
O
N
O
N
O
+
Bn
N
Bn
OH
Bn
10
O
O
O
OH
O
1, 19 R = H
2, 20 R = TBDMS
19c
20c
19d
20d
O
O
OTBDMS
OTBDMS
O
O
O
N
O
N
O
+
OTBDMS
Bn
Bn
OH
O
O
O
O
OH
O
5
21b
21a
+
+
O
O
O
O
OH
OTBDMS
OTBDMS
O
O
O
O
N
N
O
N
+
Bn
Bn
Bn
O
O
O
9
OH
OH
O
21d
21c
SCHEME 4
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

1,3-Dipolar Cycloadditions
955
The ratio of diastereoisomers was determined from 13C NMR spectra by in-
tegration of the peaks of the C-4 signals of the isoxazolidine products.
The cycloadditions were first carried out in boiling toluene with alkene 1,
2 and 5 and achiral nitrone 7. The cycloaddition led to an unseparable mix-
ture of four diastereoisomeric isoxazolidines in all cases (Table I, entries
1–3). Therefore, we focused our attention on chiral nitrones with the aim to
investigate the double asymmetric induction. The pairs of the alkene–
nitrone were chosen as “matched pairs” e.g. chiral alkenes 1 and 2 with
nitrone 10 and chiral alkene 5 with nitrones 8 and 9 (Scheme 4), since the
“mismatched pairs” cycloaddition of alkene 1 with nitrone 9 was less
selective and stereoisomers were found in the disappointing ratio of
30:25:25:20.
It is worth mentioning that the chiral D-glyceraldehyde derived nitrone 8
did not react with chiral alkene 5 under various condition (Table I, entries 4
and 5). Only starting alkene 5 was isolated from the reaction mixture. On
the other hand, the cycloaddition of the alkenes 1, 2 and 5 with nitrones 9
and 10 gave only two pairs of diastereoisomers, erythro (H-3/H-4′)-endo
(H-3/H-5)-erythro (H-5/H-4′) 19a, 20a and 21a and threo-exo-erythro 19b,
20b and 21b (Table I, entries 6, 7 and 8). The other two possible cyclo-
adducts 22c–24c and 22d–24d were not detected in the crude reaction mix-
ture by NMR spectra (Scheme 4). The cycloadditions requires very long
reaction times and the yields were not very high for the protected alkenes
TABLE I
1,3-Dipolar cycloaddition of chiral terminal alkenes 1, 2 and 5 to nitrones 7–10
Compounds ratio
Yield
Entry Alkene Nitrone Reaction conditions
%
a
b
c
d
1
2
3
4
5
6
7
8
1
2
5
5
5
1
2
5
7
7
toluene, reflux, 10 h
toluene, reflux, 17 h
toluene, reflux, 17 h
toluene, reflux, 72 h
toluene, mwa, 60 min
toluene, reflux, 38 h
toluene, reflux, 72 h
toluene, reflux, 72 h
64
74
65
–
41
54
53
–
26
32
27
–
25
8
8
6
8
–
–
–
–
–
7
10
–
8
8
–
–
–
–
10
10
9
74
45
41
82
79
80
18
21
20
–
–
–
a
Microwave, 1000 W.
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

956
Blanáriková-Hlobilová et al.:
2 and 5 (Table I, entries 7 and 8). The cycloadditions with chiral protected
alkene 6 proceded extremely slowly and selectivity was comparable with
protected alkene 5. Purification by flash chromatography allowed the isola-
tion of pure cycloadducts 19a, 20a, 21a, 20b and 21b which were identi-
fied by spectroscopic analysis, particularly NOE difference experiments. The
most important and decisive information obtained from these experiments
is the presence or absence of the NOE interaction between the protons
H-5/H-3 of the isoxazolidine ring in the corresponding exo- and endo-cyclo-
adducts. These assignments were subsequently confirmed by X-ray crystal-
lographic analysis in the case of 19a (Fig. 1).
The analysis of product configuration indicates that isoxazolidines
19a–21a arise from a cycloaddition which has occurred on the sterically
more accessible face of the nitrone, via an endo-transition state with
antiperiplanar relationship of the substituent of the alkene and N-benzyl
group of the nitrone (Scheme 5). Dipolar cycloaddition of C-α-alkoxy-
substituted nitrones have been shown to occur preferentially via transition
states in which the developing carbon–carbon bond avoids steric interac-
tion with the more bulky group. On the other hand, we assume that
isoxazolidines 19b–21b result from an exo-attack of the dipolarophile on
the (Z)-nitrones 9 and 10. It should be mentioned that there was no ther-
mal interconversion between the prepared adducts in refluxing toluene,
thus indicating that the cycloadditions proceeded irreversibly under the re-
action conditions to give the kinetically controlled products 19a–21a and
19b–21b.
O6
C7
C13
C11
O12
C10
C9
O8
N2
C21
C27
C26
C4
C25
C22
O16
C15
O1
C5
C17
C23
C28
C24
O14
C18
C19
O20
FIG. 1
X-Ray analysis (ORTEP drawing) of 19a
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

1,3-Dipolar Cycloadditions
957
OH
O
O
OH
HO
Bn
O
Bn
H
H
O
N
O
O
O
N
H
O
N
O
H
Bn
OH
OR
O
O
O
O
O
RO
O
D-erythro alkene with D-threo nitrone
19a
O
O
O
O
OTBDMS
O
O
OH
N
O
O
H
OR
O
N
O
O
H
Bn
O
H
Bn
OH
H
N
O
O
O
RO
Bn
OH
D-erythro nitrone with D-threo alkene
21a
SCHEME 5
In conclusion, the new chiral terminal alkenes derived from cyclic acetals
of D-erythrose 1–3 and D-threose 5, 6 were prepared. The 1,3-dipolar cyclo-
addition with achiral and chiral nitrones afforded the corresponding dia-
stereomeric isoxazolidines 19–21. The stereoselectivity of the cycloaddition
was dependent on the steric hindrance of the nitrone. In all cases the
cycloadditions are endo-selective. The major products were found to have
the C-3/C-4 erythro- and C-3/C-3a cis-configuration. Its formation can be ra-
tionalized by a less hindered endo-attack of the (Z)-nitrone in an antiperi-
planar manner with respect to the largest group of the cyclic acetal.
EXPERIMENTAL
All starting materials and reagents are commercially available (Fluka, Merck or Avocado) and
were used without further purification. Solvents were dried before use. Thin-layer chroma-
tography (TLC, on aluminium plates coated with silica 60F254, 0.25 mm thickness, Merck)
was used for monitoring reactions; eluents are given in the text. For column chromatogra-
phy, the flash chromatography technique was employed using silica 60 (0.040–0.063 mm,
Merck). Melting points (m.p.) were determined on a Kofler hot plate apparatus and are un-
corrected. Elemental analyses were performed by the microanalysis service of the Depart-
ment of Analytical Chemistry, Slovak University of Technology, Bratislava.
The 1H and 13C NMR spectra of deuterochloroform solutions were obtained using
Varian VXR 300 (300 MHz) instrument, tetramethylsilane being the internal reference.
Chemical shifts are given in ppm (δ-scale), coupling constants (J) in Hz. Optical rotations
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

958
Blanáriková-Hlobilová et al.:
were measured on an IBZ Messtechnik Polar-LµP polarimeter and [α]D values are given in
10–1 deg cm2 g–1
.
1,2-Dideoxy-3,5-O-ethylidene-D-erythro-pent-1-enitol (1)
To a stirred solution of methyltriphenylphosphonium bromide (12.3 g, 34.2 mmol) in THF
(50 ml) at room temperature was added 15% butyllithium in hexane (22 ml, 52.0 mmol)
over a period of 5 min. The resulting mixture was stirred at room temperature for 15 min
and then was added 2,4-O-ethylidene-D-erythrose (11; 2.5 g, 17.18 mmol) in THF (40 ml).
This mixture was stirred at reflux (65 °C) for 3 h, then was added water (100 ml) and ex-
tracted with Et2O (3 × 40 ml). The organic layers were combined, dried and concentrated
under reduced pressure. The crude product was purified by column chromatography on sil-
ica gel (16 × 2 cm) using EtOAc/hexanes (15:85) to give product 1 (769 mg, 31%) as yellow
oil with [α]2D5 –23.5 (c 1.0, EtOAc). TLC: RF 0.39 in EtOAc/hexanes (50:50). 1H NMR:
5.91 ddd, 1 H, J1trans,2 = 17.3, J1cis,2 = 10.5, J2,3 = 6.8 (H-2); 5.31–5.48 m, 2 H (H-1); 4.73 q,
1 H, J = 5.1 (CHCH3); 4.10–4.18 m, 1 H (H-4); 3.80 dd, 1 H, J3,4 = 8.6, J2,3 = 6.8 (H-3);
3.34–3.54 m, 2 H (H-5); 2.20 br s, 1 H (OH); 1.35 d, 3 H, J = 5.1 (CHCH3). 13C NMR: 134.78
(C-2), 119.26 (C-1), 98.82 (CHCH3), 82.90 (C-3), 70.40 (C-5), 65.09 (C-4), 20.52 (CHCH3).
2,4-O-Ethylidene-D-erythrose N,N-Dimethylhydrazone9 (12)
A solution of 2,4-O-ethylidene-D-erythrose (11; 3.0 g, 20.5 mmol), N,N-dimethylhydrazine
(1.2 g, 20.6 mmol), MgSO4 (6.8 g, 56.5 mmol) and a catalytic amount of 2-pyridone
(100 mg) in methanol was stirred at room temperature for 3.5 h, then was filtered through a
pad of Celite and the filtrate was evaporated. The crude product was purified by crystalliza-
tion from Et2O to give product 12 (3.3 g, 85%) as colorless solid with m.p. 99–100 °C (Et2O),
[α]2D5 –4.7 (c 1.6, CHCl3), ref.9 m.p. 97–98 °C, [α]1D8 –7.0 (c 1.6, CHCl3). TLC: RF 0.16 in
EtOAc/hexanes (50:50). For C8H16N2O3 (188.2) calculated: 51.05% C, 8.57% H, 14.88% N;
found: 51.35% C, 8.69% H, 14.7% N. IR (KBr): 3434, 3002, 2988, 2961, 2938, 2911, 2867,
2795, 2681, 2649, 1591 (C=N), 1468, 1447, 1404. 1H NMR: 6.49 d, 1 H, J1,2 = 4.4 (H-1);
4.74 q, 1 H, J5,6 = 5.1 (CHCH3); 4.12 dd, 1 H, J4A,4B = 10.3, J3,4A = 5.1 (H-4A); 3.96 dd, 1 H,
J2,3 = 8.8, J1,2 = 4.4 (H-2); 3.75 ddd, 1 H, J3,4A = 10.3, J2,3 = 8.8, J3,4B = 5.1 (H-3); 3.71 br s,
1 H (OH); 3.43 dd, 1 H, J4A,4B = 10.3, J3,4B = 10.3 (H-4B); 2.82 s, 2 × 3 H (N(CH3)2); 1.33 d,
3 H, J5,6 = 5.1 (CHCH3). 13C NMR: 132.7 (C-1), 98.5 (CHCH3), 80.2 (C-2), 69.6 (C-4), 64.3
(C-3), 42.1 (N(CH3)2), 20.1 (CHCH3).
2,4-O-Ethylidene-D-threose N,N-Dimethylhydrazone (16)
Title compound was prepared from 15 according to the procedure described for 9. The crude
product was purified by column chromatography on silica gel using EtOAc/hexanes (35:65)
to give compound 16 (79%) as colorless solid with m.p. 59–61 °C (EtOAc/petroleum ether),
[α]2D5 –95.0 (c 1.1, CHCl3). TLC: RF 0.18 in EtOAc/hexanes (50:50). For C8H16N2O3 (188.2) cal-
culated: 51.05% C, 8.57% H, 14.88% N; found: 51.10% C, 8.92% H, 14.86% N. IR (CHCl3):
3600 (OH), 3460 (OH), 2860, 2820, 2815, 1610 (C=N), 1485, 1470, 1460, 1420, 1400.
1H NMR: 6.62 d, 1 H, J1,2 = 5.1 (H-1); 4.84 q, 1 H, J5,6 = 5.1 (CHCH3); 4.30 dd, 1 H, J1,2
=
5.1, J2,3 = 0.6 (H-2); 4.12 dd, 1 H, J4A,4B = 12.0, J3,4A = 0.9 (H-4A); 3.88 dd, 1 H, J4A,4B = 12.0,
J3,4B = 0.6 (H-4B); 3.67 br s, 1 H (H-3); 3.40 br s (OH); 2.86 s, 2 × 3 H (N(CH3)2); 1.40 d, 3 H,
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

1,3-Dipolar Cycloadditions
959
J5,6 = 5.1 (CHCH3). 13C NMR: 131.2 (C-1), 99.5 (CHCH3), 78.9 (C-2), 71.6 (C-4), 64.4 (C-3),
42.4 (N(CH3)2), 21.0 (CHCH3).
3-O-tert-(Butyldimethylsilyl)-2,4-O-ethylidene-D-erythrose N,N-Dimethylhydrazone (13)
To the solution of hydrazone 12 (2.1 g, 11.2 mmol) and imidazole (1.8 g, 26.4 mmol) in
CH2Cl2 (10 ml) tert-butyldimethylsilyl chloride (1.8 g, 11.9 mmol) was added. The resulting
mixture was stirred at room temperature for 24 h, then was poured into water and extracted
with CH2Cl2 (3 × 20 ml). The organic layers were combined, dried and concentrated under
reduced pressure. The crude product was purified by column chromatography over silica gel
(16 × 2 cm) using EtOAc/hexanes (30:70) to give compound 13 (3.1 g, 97%) as colorless oil,
[α]2D5 –33.1 (c 1.0, CHCl3). TLC: RF 0.54 in EtOAc/hexanes (70:30). IR (KBr): 2955, 2930, 2886,
2859, 1605 (C=N), 1472, 1464. 1H NMR: 6.34 d, 1 H, J1,2 = 6.6 (H-1); 4.71 q, 1 H, J = 5.1
(CHCH3); 4.06 dd, 1 H, J4A,4B = 10.8, J3,4A = 5.2 (H-4A); 3.92 dd, 1 H, J2,3 = 9.0, J1,2 = 6.6
(H-2); 3.67 ddd, J3,4A = 9.9, J2,3 = 9.0, J3,4B = 5.2 (H-3); 3.39 dd, 1 H, J4A,4B = 10.8, J3,4B = 9.9
(H-4B); 2.81 s, 2 × 3 H (N(CH3)2); 1.31 d, 3 H, J5,6 = 5.1 (CHCH3); 0.80 s, 9 H (SiC(CH3)3);
0.00 and –0.03 2 × s, 2 × 3 H (Si(CH3)2). 13C NMR: 130.4 (C-1), 98.4 (CHCH3), 82.3 (C-2),
71.2 (C-4), 64.9 (C-3), 42.2 (N(CH3)2), 25.6 (SiC(CH3)3), 20.5 (CHCH3), 17.8 (SiC(CH3)3),
–4.5 and –4.8 (Si(CH3)2).
3-O-(tert-Butyldimethylsilyl)-2,4-O-ethylidene-D-threose N,N-Dimethylhydrazone (17)
Title compound was prepared from compound 16 according to the procedure described for
compound 13. The crude product was purified by column chromatography on silica gel us-
ing EtOAc/hexanes (30:70) to give 17 (96%) as colorless oil, [α]2D5 –13.4 (c 1.0, CHCl3). TLC:
RF 0.43 in EtOAc/hexanes (70:30). IR (KBr): 2955, 2930, 2886, 2859, 1605, 1472, 1464.
1H NMR: 6.62 d, 1 H, J1,2 = 6.2 (H-1); 4.79 q, 1 H, J = 5.1 (CHCH3); 4.26 dd, 1 H, J2,3 = 1.8,
J1,2 = 6.2 (H-2); 3.98 and 3.83 2 × dd, 2 × 1 H, J4A,4B = 12.3, J3,4A,B = 1.6 (H-4A); 3.61 ddd,
J3,4A = J3,4B = 1.6, J2,3 = 1.8 (H-3); 2.81 s, 2 × 3 H (N(CH3)2); 1.37 d, 3 H, J5,6 = 5.1 (CHCH3);
0.91 s, 9 H (SiC(CH3)3); 0.07 and –0.02 2 × s, 2 × 3 H (Si(CH3)2). 13C NMR: 133.4 (C-1), 98.8
(CHCH3), 80.3 (C-2), 71.8 (C-4), 66.9 (C-3), 42.5 (N(CH3)2), 25.8 (SiC(CH3)3), 21.0 (CHCH3),
18.2 (SiC(CH3)3), –4.5 and –4.7 (Si(CH3)2).
3-O-(tert-Butyldiphenylsilyl)-2,4-O-ethylidene-D-erythrose N,N-Dimethylhydrazone (14)
Title compound was prepared from hydrazone 12 and tert-butyldiphenylsilyl chloride ac-
cording to the procedure described for compound 13. The crude product was purified by
column chromatography over silica gel using EtOAc/hexanes (10:90) to give product 14
(89%) as colorless solid with m.p. 40–43 °C (EtOAc/hexanes), [α]2D5 +52.4 (c 1.0, CHCl3). TLC:
RF 0.47 in EtOAc/hexanes (30:70). For C8H16N2O3 (426.6) calculated: 67.57% C, 8.03% H,
6.57% N; found: 67.39% C, 8.10% H, 6.46% N. 1H NMR: 7.71, 7.58 and 7.36 3 × m, 10 H
(C6H5); 6.14 d, 1 H, J1,2 = 6.8 (H-1); 4.69 q, 1 H, J = 4.7 (CHCH3); 4.08 dd, 1 H, J2,3 = 8.5,
J1,2 = 6.8 (H-2); 3.83 dd, 1 H, J4A,4B = 10.7, J3,4A = 5.1 (H-4A); 3.73 m, 1 H (H-3); 3.44 dd, 1 H,
J4A,4B = 10.7, J3,4B = 9.4 (H-4B); 2.73 s, 2 × 3 H (N(CH3)2); 1.24 d, 3 H, J5,6 = 5.1 (CHCH3);
0.99 s, 9 H (SiC(CH3)3). 13C NMR: 135.9, 135.8 (C6H5, q), 134.8 (C-1), 133.1, 129.9, 129.7,
129.6, 127.6, 127.5 (C6H5), 98.6 (CHCH3), 82.4 (C-2), 71.1 (C-4), 65.7 (C-3), 42.2 (N(CH3)2),
26.6 (SiC(CH3)3), 20.5 (CHCH3), 19.2 (SiC(CH3)3).
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

960
Blanáriková-Hlobilová et al.:
3-(O-tert-Butyldiphenylsilyl)-2,4-O-ethylidene-D-threose N,N-Dimethylhydrazone (18)
Title compound was prepared from hydrazone 16 and tert-butyldiphenylsilyl chloride ac-
cording to the procedure described for compound 13. The crude product was purified by
column chromatography on silica gel using EtOAc/hexanes (15:85) to give compound 18
(85%) as colorless oil with [α]2D5 +56.7 (c 1.5, CHCl3). TLC: RF 0.42 in EtOAc/hexanes (30:70).
1H NMR: 7.71, 7.64, 7.35 3 × m, 10 H (C6H5); 6.75 d, 1 H, J1,2 = 6.0 (H-1); 4.76 q, 1 H, J =
4.6 (CHCH3); 4.22 dd, 1 H, J2,3 = 1.3, J1,2 = 6.0 (H-2); 3.70 m, 1 H (H-3); 3.68 and 3.48 2 ×
dd, 2 × 1 H, J4A,4B =12.4, J3,4A = 1.7, J3,4B = 0.9 (H-4A,B); 2.76 s, 2 × 3 H (N(CH3)2); 1.41 d, 3 H,
J5,6 = 4.6 (CHCH3); 1.07 s, 9 H (SiC(CH3)3). 13C NMR: 135.9, 135.8 (C6H5, q), 132.5 (C-1),
133.1, 129.9, 129.7, 129.6, 127.6, 127.5 (C6H5), 98.8 (CHCH3), 80.6 (C-2), 70.8 (C-4), 68.1
(C-3), 42.4 (N(CH3)2), 29.9 (SiC(CH3)3), 21.2 (CHCH3), 19.6 (SiC(CH3)3).
4-(O-tert-Butyldimethylsilyl)-1,2-dideoxy-3,5-O-ethylidene-D-erythro-pent-1-enitol (2)
Hydrazone 13 (1.5 g, 4.8 mmol) was dissolved in acetic acid (25 ml) containing water (4 ml).
Sodium nitrite (3.3 g, 48 mmol) was added in small portions to stirred solution at room
temperature during 3 h. This mixture was stirred for 1 h and then concentrated. The residue
was partioned between CHCl3 (50 ml) and water (50 ml). The aqueous layer was thoroughly
extracted with CHCl3 (3 × 15 ml) and the combined organic layers were washed with water
(30 ml) and aqueous NaHCO3 solution (50%, 30 ml), dried and concentrated to afford the
crude aldehyde. To a stirred solution of methyltriphenylphosphonium bromide (3.5 g,
9.8 mmol) in THF (10 ml) at 0–5 °C was added 15% butyllithium in hexanes (4.8 ml,
9.8 mmol) over a period of 5 min. The resulting mixture was stirred at 0–5 °C for 15 min
and then the crude aldehyde was added in THF (10 ml). This mixture was stirred at room
temperature for 5 h, then was added water (30 ml) and extracted with Et2O (3 × 20 ml). The
organic layers were combined, dried and concentrated under reduced pressure. The crude
product was purified by column chromatography over silica gel (30 × 2 cm) using EtOAc/
hexanes (4:96) to give compound 2 (614 mg, 48%) as colorless oil with [α]2D0 –35.3 (c 1.9,
CHCl3). TLC: RF 0.48 in EtOAc/hexanes (10:90). For C13H26O3Si (258.4) calculated:
60.42% C, 10.14% H; found: 60.61% C, 10.08% H. IR (KBr): 2957, 2930, 2886, 2857, 1472,
1463, 1403, 1256, 1113, 1006, 906, 871. 1H NMR: 5.86 ddd, 1 H, J1trans,2 = 16.7, J1cis,2 = 10.6,
J2,3 = 6.2 (H-2); 5.33 and 5.21 2 × m, 2 × 1 H (H-1); 4.68 q, 1 H, J = 5.0 (CHCH3); 3.76 dd,
1 H, J3,4 = 8.6, J2,3 = 6.2 (H-3); 3.43 m, 1 H (H-4); 3.35 m, 2 H (H-5); 1.31 d, 3 H, J = 5.0
(CHCH3); 0.82 s, 9 H (SiC(CH3)3); 0.00 and –0.04 2 × s, 2 × 3 H (Si(CH3)2). 13C NMR: 135.5
(C-2), 118.1 (C-1), 98.9 (CHCH3), 82.9 (C-3), 71.2 (C-5), 66.9 (C-4), 26.0 (SiC(CH3)3), 20.9
(CHCH3), 18.5 (SiC(CH3)3), –4.2 and –4.0 (Si(CH3)2).
4-(O-tert-Butyldimethylsilyl)-1,2-dideoxy-3,5-O-ethylidene-D-threo-pent-1-enitol (5)
Title compound was prepared from compound 17 according to the procedure described for
compound 2. The crude product was purified by column chromatography over silica gel us-
ing EtOAc/hexanes (2:98) to give compound 5 (46%) as colorless oil with [α]2D0 –30.7 (c 1.9,
CHCl3). TLC: RF 0.50 in EtOAc/hexanes (10:90). For C13H26O3Si (258.4) calculated:
60.42% C, 10.14% H; found: 60.58% C, 10.10% H. IR (KBr): 2955, 2929, 2885, 2856, 1473,
1463, 1403, 1256, 1183, 1113, 1110, 1006, 935, 906, 876, 837. 1H NMR: 5.86 ddd, 1 H,
J1trans,2 = 17.3, J1cis,2 = 10.5, J2,3 = 6.7 (H-2); 5.22 and 5.10 2 × m, 2 × 1 H (H-1); 4.69 q, 1 H,
J = 5.0 (CHCH3); 4.04 dd, 1 H, J3,4 = 1.7, J2,3 = 6.7 (H-3); 3.91 and 3.73 2 × dd, 2 × 1 H,
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

1,3-Dipolar Cycloadditions
961
J4,5A = J4,5B = 1.6, J5A,5B = 12.0 (H-4A,B); 3.42 dd, 1 H, J3,4 = 1.7, J4,5A = J4,5B = 1.6 (H-4);
1.29 d, 3 H, J = 5.0 (CHCH3); 0.84 s, 9 H (SiC(CH3)3); 0.00 and –0.03 2 × s, 2 × 3 H (Si(CH3)2).
13C NMR: 136.1 (C-2), 117.3 (C-1), 99.0 (CHCH3), 81.3 (C-3), 72.2 (C-5), 67.4 (C-4), 26.2
(SiC(CH3)3), 21.8 (CHCH3), 18.6 (SiC(CH3)3), –3.9 and –4.1 (Si(CH3)2).
4-(O-tert-Butyldiphenylsilyl)-1,2-dideoxy-3,5-O-ethylidene-D-erythro-pent-1-enitol (3)
Title compound was prepared from compound 14 according to the procedure described for
compound 2. The crude product was purified by column chromatography on silica gel using
EtOAc/hexanes (5:95) to give compound 3 (58%) as colorless oil with [α]2D0 –3.3 (c 0.3,
CHCl3). TLC: RF 0.58 in EtOAc/hexanes (10:90). 1H NMR: 7.65 and 7.62 2 × m, 10 H (C6H5);
5.86 ddd, 1 H, J1trans,2 = 17.1, J1cis,2 = 10.3, J2,3 = 6.2 (H-2); 5.39 and 5.21 2 × m, 2 × 1 H
(H-1); 4.68 q, 1 H, J = 5.1 (CHCH3); 3.92 m, 1 H (H-3); 3.75 dd, 1 H, J4,5A = 5.1, J5A,5B = 10.7
(H-5A); 3.59 ddd, 1 H, J4,5A = 5.1, J4,5B = 9.8, J4,3 = 9.0 (H-4); 3.38 dd, 1 H, J5A,5B = 10.7, J4,5B
=
9.8 (H-5B); 1.26 d, 3 H, J = 5.1 (CHCH3); 1.04 s, 9 H (SiC(CH3)3). 13C NMR: 136.0, 135.8
(C6H5, q), 133.9, 132.9, 130.0, 129.9, 127.7 (C6H5), 135.2 (C-2), 118.4 (C-1), 98.5 (CHCH3),
82.7 (C-3), 71.1 (C-5), 67.3 (C-4), 26.9 (SiC(CH3)3), 20.5 (CHCH3), 19.3 (SiC(CH3)3).
4-(O-tert-Butyldiphenylsilyl)-1,2-dideoxy-3,5-O-ethylidene-D-threo-pent-1-enitol (6)
Title compound was prepared from compound 18 according to the procedure described for
compound 2. The crude product was purified by column chromatography on silica gel using
EtOAc/hexanes (2:98) to give product 6 (48%) as colorless oil with [α]2D0 –21.4 (c 0.35,
CHCl3). TLC: RF 0.60 in EtOAc/hexanes (10:90). 1H NMR: 7.81, 7.69 and 7.36 3 × m, 10 H
(C6H5); 6.06 ddd, 1 H, J1trans,2 = 17.5, J1cis,2 = 10.7, J2,3 = 6.8 (H-2); 5.27 and 5.10 2 × m, 2 ×
1 H (H-1); 4.74 q, 1 H, J = 5.1 (CHCH3); 4.06 dd, 1 H, J3,4 = 1.3, J2,3 = 6.8 (H-3); 3.71 dd, 1 H,
J4,5A = 1.3, J5A,5B = 12.4 (H-4A); 3.56 dd, 1 H, J3,4 = J4,5A = J4,5B = 1.3 (H-4); 3.49 dd, 1 H, J4,5B
=
1.3, J5A,5B = 12.4 (H-4B); 1.43 d, 3 H, J = 5.1 (CHCH3); 1.09 s, 9 H (SiC(CH3)3). 13C NMR:
136.1 (C-2), 135.9, 134.1 (C6H5, q), 133.4, 129.6, 129.5, 127.5, 127.4 (C6H5), 116.9 (C-1),
98.6 (CHCH3), 80.9 (C-3), 70.8 (C-5), 67.9 (C-4), 26.9 (SiC(CH3)3), 21.1 (CHCH3), 19.6
(SiC(CH3)3).
General Procedure for Cycloaddition
To a stirred solution of an alkene (1.0 mmol) in toluene (10 ml) was added a nitrone
(3 mmol) in three portions after 10 h each and the solution was heated at reflux (110 °C) for
several hours. The resulting mixture was evaporated under reduced pressure.
(3R,5S)-2-Benzyl-3-[(2S,4R,5R)-5-hydroxy-2-methyl-1,3-dioxan-4-yl]-5-[(2R,4S,5R)-5-hydroxy-2-
methyl-1,3-dioxan-4-yl]isoxazolidine (19a). A crude mixture of diastereoisomers obtained in
ratio 82:18 was purified by column chromatography on silica gel eluting with EtOAc/
hexanes to give the major product 19a (74%) as a colorless crystals with m.p. 155–156 °C
(EtOAc/hexanes), [α]2D5 +27.8 (c 1.0, CHCl3). TLC: RF 0.37 in EtOAc/hexanes (40:60). For
C
20H29NO7 (395.5) calculated: 60.75% C, 7.39% H, 3.54% N; found: 60.60% C, 7.42% H,
3.49% N. IR (KBr): 3456, 2991, 2937, 2864, 1454, 1411, 1371, 1225, 1121, 1082, 979, 821.
1H NMR: 7.32 m, 5 H (C6H5); 4.69 and 4.64 2 × q, 2 × 1 H, J = 5.1, 5.0 (H-2′, H-2′′);
4.47 ddd, 1 H, J4B,5 = 6.4, J4A,5 = 8.4, J4′′,5 = 5.4 (H-5); 4.07 dd, 1 H, J6A′′,6B′′ = 10.8, J6A′′,5′′
=
5.3 (H-6A′′); 4.03 dd, 1 H, J6A′,6B′ = 12.1, J6A′,5′ = 2.1 (H-6A′); 4.00 and 3.95 2 × d, 2 × 1 H, J =
13.1 (CH2C6H5); 3.77 m, 2 H (H-5′′, H-6B′); 3.52 m, 3 H (H-3, H-4′, H-5′); 3.39 dd, 1 H, J4′′,5
=
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

962
Blanáriková-Hlobilová et al.:
5.4, J4′′,5′′ = 9.1 (H-4′′); 3.32 dd, 1 H, J6A′′,6B′′ = 10.8, J6B′′,5′′ = 10.0 (H-6B′′); 2.90 br s, 1 H
(OH); 2.57 ddd, 1 H, J4A,5 = 8.4, J3,4A = 8.3, J4A,4B = 13.0 (H-4A); 2.37 ddd, 1 H, J4B,5 = 6.4,
J3,4B = 4.4, J4A,4B = 13.0 (H-4B); 1.35 and 1.30 2 × d, 2 × 3 H, J = 5.1, 5.0 (CH3). 13C NMR:
130.1 (C6H5, q), 129.6, 129.8, 129.1, 128.9, 128.8 (C6H5), 100.1, 98.9 (C-2′, C-2′′), 80.8
(C-4′′), 79.5 (C-4′), 78.5 (C-5), 72.2 (C-6′), 70.5 (C-6′′), 65.2 (C-5′), 64.8 (C-3), 63.9 (C-5′′),
61.6 (CH2C6H5), 32.6 (C-4), 21.3, 20.9 (2 × CH3).
(3R,5S)-2-Benzyl-5-{(2R,4S,5R)-5-[(tert-butyldimethylsilyl)oxy]-2-methyl-1,3-dioxan-4-yl}-
3-(2S,4R,5R)-5-hydroxy-2-methyl-1,3-dioxan-4-yl)isoxazolidine (20a) and (3R,5R)-2-benzyl-5-
{(2R,4S,5R)-5-[(tert-butyldimethylsilyl)oxy]-2-methyl-1,3-dioxan-4-yl}-3-(2S,4R,5R)-5-hydroxy-
2-methyl-1,3-dioxan-4-yl)isoxazolidine (20b). The crude reaction mixture of diastereoisomers
in ratio 82:18 was purified by column chromatography on silica gel eluting with EtOAc/
hexanes to give the starting alkene 2 (19%) as first fraction, the minor product 20b (10%) as
a colorless oil and the major product 20a (35%) in the third fraction as a colorless oil.
Data for 20a: [α]2D5 –8.8 (c 1.2, CHCl3). TLC: RF 0.48 in EtOAc/hexanes (20:80). IR (film):
3456, 2991, 2929, 2856, 1451, 1410, 1389, 1225, 1159, 1082, 956, 979, 821. 1H NMR: 7.47
and 7.34 2 × m, 5 H (C6H5); 4.79 and 4.78 2 × q, 2 × 1 H, J = 5.0 (H-2′, H-2′′); 4.44 m, 1 H
(H-5); 4.21 and 4.14 2 × d, 2 × 1 H, J = 13.2 (CH2C6H5); 4.15 dd, 1 H, J6A′,6B′ = 11.8, J6A′,5′
=
1.7 (H-6A′); 4.07 dd, 1 H, J6A′′,6B′′ = 10.7, J6A′′,5′′ = 5.3 (H-6A′′); 3.88 m, 1 H (H-5′); 3.85 dd,
1 H, J6A′,6B′ = 11.8, J6B′,5′ = 1.3 (H-6B′); 3.81 ddd, 1 H, J6A′′,5′′ = 5.3, J6B′′,5′′ = 8.8, J4′′,5′′ = 10.0
(H-5′′); 3.61 m, 2 H, H-3 (H-4′); 3.76 br s, 1 H (OH); 3.39 dd, 1 H, J4′′,5′′ = 10.0, J4′′,5 = 10.6
(H-4′′); 3.33 dd, 1 H, J6A′′,6B′′ = 10.7, J6B′′,5′′ = 8.8 (H-6B′′); 2.60 and 2.34 2 × m, 2 × 1 H
(H-4A,B); 1.47 and 1.43 2 × d, 2 × 3 H, J = 5.0 (2 × CH3); 0.87 s, 9 H (C(CH3)3); 0.00 and
–0.03 2 × s, 2 × 3 H (Si(CH3)2). 13C NMR: 138.1 (C6H5, q), 129.6, 128.1, 127.0 (C6H5), 99.7,
99.0 (C-2′, C-2′′), 80.4 (C-4′′), 78.6 (C-4′), 75.5 (C-5), 71.9 (C-6′), 71.4 (C-6′′), 65.5 (C-3),
63.3, 63.0 (C-5′, C-5′′), 62.5 (CH2C6H5), 30.2 (C-4), 25.6 (C(CH3)3), 20.9, 20.6 (2 × CH3),
17.8 (C(CH3)3), –4.9 and –5.2 (Si(CH3)2).
Data for compound 20b: [α]2D5 3.3 (c 1.5, CHCl3). TLC: RF 0.45 in EtOAc/hexanes (20:80).
IR (film): 3456, 3299, 2929, 2856, 1451, 1410, 1389, 1225, 1159, 1082, 956, 979, 821. 1H
NMR: 7.21 m, 5 H (C6H5); 4.60 m, 3 H, H-2′, H-2′′ (H-5); 3.96 dd, 1 H, J6A′,6B′ = 11.8, J6A′,5′
=
1.8 (H-6A′); 3.93 dd, 1 H, J6A′′,6B′′ = 10.3, J6A′′,5′′ = 4.9 (H-6A′′); 3.90 and 3.73 2 × d, 2 × 1 H,
J = 12.3 (CH2C6H5); 3.73 m, 1 H (H-5′); 3.68 dd, 1 H, J6A′,6B′ = 11.8, J6B′,5′ = 1.3 (H-6B′); 3.55 m,
3 H (H-3, H-4′, H-4′′); 3.39 m, 1 H (H-5′′); 3.28 dd, 1 H, J6A′′,6B′′ = 10.3, J6B′′,5′′ = 10.0 (H-6B′′);
2.50 ddd, 1 H, J3,4A = 2.0, J4A,5 = 6.4, J4A,4B = 12.6 (H-4A); 2.33 br s, 1 H (OH); 2.28 ddd, 1 H,
J3,4B = 9.4, J4B,5 = 8.0, J4A,4B = 12.6 (H-4B); 1.28 and 1.22 2 × d, 2 × 3 H, J = 5.0 (2 × CH3);
0.83 s, 9 H (C(CH3)3); 0.00 and –0.01 2 × s, 2 × 3 H (Si(CH3)2). 13C NMR: 137.5 (C6H5, q),
129.6, 128.7, 128.9, 127.9 (C6H5), 100.1, 98.7 (C-2′, C-2′′), 79.5, 79.2 (C-4′, C-4′′), 76.1 (C-5),
73.4 (C-6′), 71.6 (C-6′′), 64.8 (C-5′′), 64.1 (C-3), 63.7 (C-5′′), 60.8 (CH2C6H5), 27.7 (C-4), 26.0
(C(CH3)3), 21.3, 20.9 (2 × CH3), 18.2 (C(CH3)3), –3.8 and –4.6 (Si(CH3)2).
(3S,5R)-2-Benzyl-5-{(2S,4R,5R)-5-[(tert-butyldimethylsilyl)oxy]-2-methyl-1,3-dioxan-4-yl}-3-
(2R,4S,5R)-5-hydroxy-2-methyl-1,3-dioxan-4-yl)isoxazolidine (21a) and (3S,5S)-2-benzyl-5-
{(2S,4R,5R)-5-[(tert-butyldimethylsilyl)oxy]-2-methyl-1,3-dioxan-4-yl}-3-(2R,4S,5R)-5-hydroxy-2-methyl-
1,3-dioxan-4-yl)isoxazolidine (21b). The crude reaction mixture was purified by column chro-
matography on silica gel eluting with EtOAc/hexanes to give the starting alkene 5 (20%) as
first fraction, the minor product 21b (9%) as a colorless oil and the major product 21a
(32%) in the third fraction as a colorless oil.
Data for compound 21a: [α]2D5 –14.0 (c 1.2, CHCl3). TLC: RF 0.45 in EtOAc/hexanes
(20:80). IR (film): 3448, 2991, 2930, 2857, 1463, 1410, 1389, 1225, 1159, 1082, 956, 979,
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

1,3-Dipolar Cycloadditions
963
821. 1H NMR: 7.23 m, 5 H (C6H5); 5.30 br s, 1 H (OH); 4.70 and 4.51 2 × q, 2 × 1 H, J = 5.0
(H-2′, H-2′′); 4.45 m, 1 H (H-5); 4.01 and 3.66 2 × d, 2 × 1 H, J = 11.7 (CH2C6H5); 3.93 dd,
1 H, J6A′,6B′ = 10.4, J6A′,5′ = 4.3 (H-6A′); 3.90 dd, 1 H, J6A′′,6B′′ = 12.3, J6A′′,5′′ = 1.7 (H-6A′′);
3.69 dd, 1 H, J6A′′,6B′′ = 12.3, J6B′′,5′′ = 1.9 (H-6B′′); 3.53 m, 2 H (H-4′′, H-5′′); 3.18 m, 4 H (H-3,
H-4′, H-5′, H-6B′); 2.45 m, 2 H (H-4A,B); 1.27, 1.18 2 × d, 2 × 3 H, J = 5.0 (2 × CH3); 0.86 s,
9 H (C(CH3)3); 0.00 and –0.09 2 × s, 2 × 3 H (Si(CH3)2). 13C NMR: 135.6 (C6H5, q), 129.7,
129.2, 128.5, 127.9 (C6H5), 99.5, 99.2 (C-2′, C-2′′), 80.5 (C-4′′), 79.6 (C-4′), 78.0 (C-5), 71.9
(C-6′), 70.3 (C-6′′), 67.9, 66.6 (C-3, C-5′), 64.9 (C-5′′), 60.9 (CH2C6H5), 31.4 (C-4), 26.3
(C(CH3)3), 21.4, 20.9 (2 × CH3), 18.6 (C(CH3)3), –4.0 and –4.4 (Si(CH3)2).
Data for compound 21b: [α]2D5 +53.4 (c 1.3, CHCl3).TLC: RF 0.48 in EtOAc/hexanes (20:80).
IR (film): 3363, 2991, 2929, 2855, 1597, 1451, 1408, 1367, 1253, 1159, 1104, 1052, 1002,
956, 979, 821. 1H NMR: 7.44 m, 5 H (C6H5); 4.88 and 4.78 2 × q, 2 × 1 H, J = 5.0 (H-2′,
H-2′′); 4.78 br s, 1 H (OH); 4.31 m, 1 H (H-5); 4.27 dd, 1 H, J6A′,6B′ = 10.8, J6A′,5′ = 5.3 (H-6A′);
4.23 and 4.05 2 × d, 2 × 1 H, J = 13.2 (CH2C6H5); 4.08 dd, 1 H, J6A′′,6B′′ = 12.2, J6A′′,5′′ = 1.7
(H-6A′′); 3.98 m, 1 H (H-5′′); 3.90 dd, 1 H, J6A′′,6B′′ = 12.2, J6B′′,5′′ = 1.5 (H-6B′′); 3.69 dd, 1 H,
J4′′,5′′ = 1.6, J5,5′′ = 7.5 (H-4′′); 3.61 m, 3 H (H-3, H-4′, H-5′); 3.51 dd, 1 H, J6A′,6B′ = 10.8,
J6B′,5′ = 9.9 (H-6B′); 2.75 ddd, 1 H, J3,4A = 4.5, J4A,5 = 7.4, J4A,4B = 11.8 (H-4A); 2.50 m, 1 H
(H-4B); 1.47 and 1.43 2 × d, 2 × 3 H, J = 5.0 (CH3); 0.86 s, 9 H (C(CH3)3); 0.07 and –0.14
2 × s, 2 × 3 H (Si(CH3)2). 13C NMR: 136.8 (C6H5, q), 128.8, 128.1, 126.3 (C6H5), 99.5, 99.3
(C-2′, C-2′′), 81.4 (C-4′′), 79.3 (C-4′), 77.0 (C-5), 72.2 (C-6′′), 70.4 (C-6′), 68.1, 64.5 (C-3,
C-5′), 63.0 (CH2C6H5), 62.5 (C-5′′), 33.3 (C-4), 26.2 (C(CH3)3), 21.4, 20.9 (2 × CH3), 18.5
(C(CH3)3), –4.5 and –4.7 (Si(CH3)2).
X-Ray Diffraction Study
CCDC 199965 (for 19a) contains the supplementary crystallographic data for this paper.
These data can be obtained free of charge via www.ccdc.cam.ac.uk/conts/retrieving.html (or
from the Cambridge Crystallographic Data Centre, 12, Union Road, Cambridge, CB2 1EZ,
UK; fax: +44 1223 336033; or deposit@ccdc.cam.ac.uk).
The authors are grateful to the Slovak Grant Agency (No. 1/7314/20).
REFERENCES
1. a) Tufariello J. J. in: 1,3-Dipolar Cycloaddition Chemistry (A. Padwa, Ed.), Chap. 9, p. 83.
Wiley–Interscience, New York 1984; b) Torssell K. B. G.: Nitrile Oxides, Nitrones, and
Nitronates. VCH Publishers, New York 1988; c) Gothelf K. V., Jorgensen K. V.: Chem. Rev.
(Washington, D. C.) 1988, 98, 863.
2. Fišera L., Al-Timari U. A. R., Ertl P.: Cycloadditions in Carbohydrate Chemistry, p. 158. ACS
Monograph. Am. Chem. Soc., Washington 1992.
3. Frederickson M.: Tetrahedron 1997, 53, 403.
4. a) Al-Timari U. A. R., Fišera L., Ertl P., Goljer I., Prónayová N.: Monatsh. Chem. 1992,
123, 999; b) Kubán J., Blanáriková I., Fišera L., Prónayová N.: Chem. Pap. 1997, 51, 378.
5. a) Denmark S. E., Hurd R. A., Sacha H. J.: J. Org. Chem. 1997, 62, 1668; b) McGaig A. E.,
Meldrum K. P., Wightman R. H.: Tetrahedron 1998, 54, 9429; c) Hall A., Meldrum K. P.,
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

964
Blanáriková-Hlobilová et al.:
Therond P. R., Wightman R. H.: Synlett 1997, 123; d) Müller R., Leibold T., Pätzel M.,
Jäger V.: Angew. Chem., Int. Ed. Engl. 1994, 33, 1295.
6. Taylor D. L., Nash R., Fellows L. E., Kang M. S., Syms A. S.: Antivir. Chem. Chemother.
1992, 3, 273.
7. a) Kubán J., Blanáriková I., Fišera L., Jarošková L., Fengler-Veith M., Jäger V., Kozíšek J.,
Humpa O., Langer V.: Tetrahedron 1999, 55, 9501; b) Kubán J., Kolarovič A., Fišera L.,
Jäger V., Humpa O., Prónayová N., Ertl P.: Synlett 2001, 1862; c) Kubán J., Kolarovič A.,
Fišera L., Jäger V., Humpa O., Prónayová N.: Synlett 2001, 1866; d) Fischer R., Drucková A.,
Fišera L., Rybár A., Hametner C., Cyranski M. K.: Synlett 2002, 1113.
8. a) Barker R., MacDonald D. L.: J. Am. Chem. Soc. 1960, 82, 2301; b) Ball D. H.: J. Org.
Chem. 1966, 31, 220.
9. Wróblewski A. E: Z. Naturforsch., B: Chem. Sci. 1985, 40, 407.
10. Kampf A., Felstien A., Dimant E.: Carbohydr. Res. 1968, 6, 220.
Collect. Czech. Chem. Commun. (Vol. 68) (2003)