The asymmetric hetero-Diels-Alder reaction and addition of allylic organometallics to 10-N,N-dicyclohexylsulphamoyl-(2R)-isobornyl glyoxylate

Article abstract of DOI:10.1016/S0957-4166(99)00212-8

The recent development of very effective chiral auxiliaries has led to the design of 10-N,N-dicyclohexylsulphamoyl-(R)-isoborneol, which is similar to Oppolzer's (2R)-bornane-10,2-sultam but less effective on account of a less rigid structure. 10-N,N-Dicyclohexylsulphamoyl-(R)-isobornyl glyoxylate was examined in Diels-Alder and organometallic addition reactions. The results obtained were compared with those achieved by application of N-glyoxyloyl-(2R)-bornane-10,2-sultam.

Full text of DOI:10.1016/S0957-4166(99)00212-8

Pergamon
Tetrahedron: Asymmetry 10 (1999) 2101–2111
The asymmetric hetero-Diels–Alder reaction and addition of
allylic organometallics to 10-N,N-dicyclohexylsulphamoyl-
(2R)-isobornyl glyoxylate
Anna Czapla,a Artur Chajewski,a Katarzyna Kiegiel,a Tomasz Bauer,a Zbigniew Wielogorski,a
Zofia Urbanczyk-Lipkowskab and Janusz Jurczak a,b,∗
aDepartment of Chemistry, University of Warsaw, Pasteura 1, PL-02-093 Warsaw, Poland
bInstitute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, PL-01-224 Warsaw, Poland
Received 31 March 1999; accepted 25 May 1999
Abstract
The recent development of very effective chiral auxiliaries has led to the design of 10-N,N-
dicyclohexylsulphamoyl-(R)-isoborneol, which is similar to Oppolzer’s (2R)-bornane-10,2-sultam but less
effective on account of a less rigid structure. 10-N,N-Dicyclohexylsulphamoyl-(R)-isobornyl glyoxylate was
examined in Diels–Alder and organometallic addition reactions. The results obtained were compared with those
achieved by application of N-glyoxyloyl-(2R)-bornane-10,2-sultam. © 1999 Elsevier Science Ltd. All rights
reserved.
1. Introduction
In recent years, we have introduced a highly effective glyoxylic acid derivative 2,1,2 bearing Oppolzer’s
chiral auxiliary 13 (Scheme 1). Compound 2 was shown to be the reagent of choice for the hetero-
Diels–Alder reaction,4 providing a straightforward route to enantiomerically pure deoxy and amino-
deoxy sugars.5,6 It was also successfully applied in an ene reaction7 and an aldol-type addition to 2-
trimethylsilyloxyfuran8 furnishing the corresponding products with very high asymmetric induction. In
organometallic additions, compound 2 has shown some limitations. Addition of allyltrimethylsilane to
compound 2, catalyzed by Lewis acids, provided the corresponding homoallylic alcohols with good to
excellent diastereoselectivity,9 but the labile nature of the amide bond in N-glyoxyloyl-(2R)-bornane-
10,2-sultam 2 precludes use of classical organometallic reagents, e.g. Grignard compounds, in this type
of reaction. To this end, we decided to prepare the glyoxylate bearing 10-N,N-dicyclohexylsulphamoyl-
∗
Corresponding author. E-mail: jjurczak@chem.uw.edu.pl
0957-4166/99/$ - see front matter © 1999 Elsevier Science Ltd. All rights reserved.
PII: S0957-4166(99)00212-8

2102
A. Czapla et al. / Tetrahedron: Asymmetry 10 (1999) 2101–2111
(R)-isoborneol 3, another camphor-10-sulfonic acid-derived chiral auxiliary with a high diastereodiffer-
entiating power, as shown by Oppolzer et al.10,11
Scheme 1.
2. Results and discussion
2.1. Synthesis of 10-N,N-dicyclohexylsulphamoyl-(R)-isobornyl glyoxylate 5
10-N,N-Dicyclohexylsulphamoyl-(R)-isoborneol 3 was prepared according to a known procedure.10
Reaction of 3 with acrylic acid in the presence of 2-chloro-N-methylpyridinium iodide furnished the
corresponding acrylate 4,12 which was used in the synthesis of 10-N,N-dicyclohexylsulphamoyl-(R)-
isobornyl glyoxylate 5. Thus, ozonolysis of 4, followed by quenching with dimethyl sulfide, gave a
crystalline product which turned out to be a mixture of 10-N,N-dicyclohexylsulphamoyl-(R)-isobornyl
1
glyoxylate 5 and its methyl hemiacetal 6 in a ratio of 1:2, as revealed by H NMR. This mixture was
converted to the pure glyoxylate 5 by heating at 100°C under high vacuum (Scheme 2).
Scheme 2. Reagents and reaction conditions: (a) acrylic acid, 2-chloro-1-methylpyridinium iodide; (b) O3, CH2Cl2:MeOH (6:8);
(c) Me2S, −78°C; (d) 100°C, 0.5 torr, 2 h

A. Czapla et al. / Tetrahedron: Asymmetry 10 (1999) 2101–2111
2103
2.2. The hetero-Diels–Alder reaction of 5 with 1-methoxybuta-1,3-diene 7
The properties of this new chiral glyoxylate were first checked in the hetero-Diels–Alder reaction with
1-methoxybuta-1,3-diene 7. The high-pressure technique13 and/or Eu(fod)3 catalysis14,15 were applied in
order to improve the asymmetric induction. The cycloaddition of diene 7 to chiral dienophile 5 provided
four cycloadducts: two cis-diastereoisomers 8 and 10 by endo addition, and two trans-diastereoisomers 9
and 11 by exo addition. The crude reaction mixture was subjected to acidic isomerization with pyridinium
p-toluenesulphonate (PPTS),16 which gave two trans-diastereoisomers 9 and 11 separable via flash
chromatography (Scheme 3). The results of the [4+2] cycloaddition are presented in Table 1.
Scheme 3. Reagents and reaction conditions: (a) 20°C, CH2Cl2, the amounts of catalyst and the pressure are indicated in Table 1;
(b) PPTS, MeOH, rt, overnight
According to the X-ray analysis of a single crystal obtained from the pure diastereoisomer 11 the
R-configuration at C-20 was established (Fig. 1).
The Diels–Alder reaction was carried out under various conditions. In the beginning, when we
examined the diastereomeric excess and chemical yield under ambient conditions, the products were
obtained in rather low chemical yields and diastereomeric excesses (25% and 34% d.e., respectively) with
the predomination of the (R)-diastereoisomer 11 (Table 1, entry 1). This indicates that the glyoxylate 5 is
a less active dienophile than N-glyoxyloyl-(2R)-bornane-10,2-sultam 2. The application of high pressure
caused inversion of the direction of asymmetric induction and in this case the (S)-diastereoisomer 9

2104
A. Czapla et al. / Tetrahedron: Asymmetry 10 (1999) 2101–2111
Table 1
The asymmetric [4+2] cycloaddition of diene 7 to heterodienophile 5
Figure 1. Molecular structure of compound 11
was predominant (entry 2). We also studied the relationship between the molar equivalent of Eu(fod)3
added and diastereoselectivity (entries 3–6). The best result in terms of both chemical yields and
diastereoisomeric excess was obtained with 5% of the catalyst (entry 6).
For a rationalization of our results, we postulate two preferred conformations of heterodienophile. On
account of the strain of the O–CO bond, and as suggested by X-ray analysis, the conformations A and
B should predominate (Scheme 4). The approach of diene 7 to dienophile 5 should occur from the less
hindered side of the sultam group.
The CO/CHO s-trans-conformation B is favoured under normal conditions, due to an unfavourable

A. Czapla et al. / Tetrahedron: Asymmetry 10 (1999) 2101–2111
2105
Scheme 4.
interaction of the CO/CHO in s-cis planar conformer A, as proposed by Oppolzer et al.10,11 for
[4+2] cycloaddition of cyclopentadiene to 10-N,N-dicyclohexylsulphamoyl-(R)-isobornyl acrylate 4 and
confirmed by X-ray analysis.12,17 When using Eu(fod)3, the s-trans-conformer is also preferred; chelation
involves the carbonyl group and one of the sulphonyl oxygen atoms, and similarly, as in the former case,
unfavourable interaction of (Eu) O_C/CHO is eliminated.
2.3. Organometallic addition to 10-N,N-dicyclohexylsulphamoyl-(R)-isobornyl glyoxylate 5
The asymmetric effectiveness of 10-N,N-dicyclohexylsulphamoyl-(R)-isobornyl glyoxylate 5 was
also examined in nucleophilic addition reactions (Scheme 5). Two approaches for obtaining the
homoallylic alcohol were undertaken. Firstly, the addition of an allyl-Grignard reagent to 10-N,N-
dicyclohexylsulphamoyl-(2R)-isobornyl glyoxylate 5 was studied (Table 2). The results were unsatis-
factory (40% d.e.), but remarkably advantageous in comparison to those achieved by application of
N-glyoxyloyl-(2R)-bornane-10,2-sultam 2.9 An addition of 1 equivalent of LiCl did not improve the
stereoselectivity; however, a slight increase of chemical yield (50%) was observed.
Scheme 5. Reagents and reaction conditions: (a) allylmagnesium chloride, −78°C, THF; (b) allyltrimethylsilane, Lewis acid,
CH2Cl2, the other conditions: see Table 2; (c) Ac2O, py, rt, 3 h
Next, we examined the addition of allyltrimethylsilane to 10-N,N-dicyclohexylsulphamoyl-(2R)-
isobornyl glyoxylate 5 in the presence of Lewis acids (Table 3). The diastereoisomeric ratio (12/13) was
1
determined by H NMR spectroscopy. The crude reaction mixture was subjected to acetylation; at this
stage diastereoisomeric products 14 and 15 were easily separated into single diastereoisomers via flash
chromatography and then 15 was recrystallized. The relative configuration within this diastereoisomer
was established by X-ray analysis. The results are presented in Fig. 2.
Several aspects of the data shown in Table 3 are noteworthy. The enantiomeric excesses, as well as
the chemical yields, were lower then those obtained with N-glyoxyloyl-(2R)-bornane-10,2-sultam 2 as
the chiral substrate. The application of various catalysts failed to improve substantially either of these

2106
A. Czapla et al. / Tetrahedron: Asymmetry 10 (1999) 2101–2111
Table 2
The asymmetric addition of allylmagnesium chloride to glyoxylate 5
Table 3
The asymmetric addition of allyltrimethylsilane to glyoxylate 5
experimental variables. The best results were obtained using strong Lewis acids, such as TiCl4 and SnCl4
(entries 4 and 6, respectively).
The results obtained for the reaction catalyzed by these Lewis acids could be explained by predom-
inance of s-cis conformer A (Scheme 4), that leads to the product of S-absolute configuration. What is
more, in the case of a deficiency of the catalyst (0.5 equiv. of TiCl4) the product with the opposite absolute
configuration was obtained, probably as a result of the predominance of s-trans conformer B. The use of
Lewis acids such as BF3·Et2O, ZnBr2 or ZnCl2, that have weak chelating properties, results in very poor
asymmetric induction, probably due to the presence of both conformers A and B in the transition state.
3. Experimental
3.1. General
Optical rotations were recorded using a JASCO DIP-360 polarimeter with a thermally jacketed 10
cm cell. IR spectra were obtained on a Perkin–Elmer Spectrum 2000 and Perkin–Elmer 1640 FTIR
1
spectrophotometers in KBr pellets. H NMR and 13C NMR spectra were recorded using a Bruker AM
500 spectrometer and Varian Unity Plus (200 MHz and 500 MHz). All chemical shifts are quoted in

A. Czapla et al. / Tetrahedron: Asymmetry 10 (1999) 2101–2111
2107
Figure 2. Molecular structure of compound 15
parts per million relative to tetramethylsilane (δ, 0.00 ppm) and coupling constants (J) are given in hertz.
Mass spectra were recorded on an AMD-604 Intectra instrument using the electron impact (EI) and
LSIMS techniques. Flash column chromatography was performed according to Still et al.18 on silica gel
(Kieselgel-60, Merck, 200–400 mesh). 1-Methoxybuta-1,3-diene was prepared according to a literature
procedure.19 Reactions with Lewis acids were carried out under an argon atmosphere with anhydrous
solvents that had been previously dried using standard laboratory methods.
3.2. Preparation of 10-N,N-dicyclohexylsulphamoyl-(2R)-isobornyl acrylate 410
A mixture of alcohol 3 (0.56 mmol), N(nPr)3 (5.6 mmol) and acrylic acid (1.41 mmol) in toluene (3.8
mL) was added to α-chloro-N-methylpyridinium iodide (720 mg, 3.8 mmol). Heating of the mixture at
reflux for 1 h, dilution with toluene, drying, evaporation and crystallization gave acrylate 4 (189 mg,
70%).
3.3. Preparation of 10-N,N-dicyclohexylsulphamoyl-(2R)-isobornyl glyoxylate 5 and its methyl hemi-
acetal 6
The solution of 10-N,N-dicyclohexylsulphamoyl-(2R)-isobornyl acrylate 4 (0.413 g, 0.91 mmol) in a
8:6 mixture of CH2Cl2:MeOH was cooled to −78°C and treated with ozone until the solution was blue.
The dimethyl sulfide (2 mL) was then added at −78°C, and the mixture was stirred at room temperature
over a period of 15 h. After careful evaporation of the solvents and an excess of dimethyl sulfide, a
mixture of 5 and 6 was obtained (0.351 g, 85%).

2108
A. Czapla et al. / Tetrahedron: Asymmetry 10 (1999) 2101–2111
3.4. Preparation of (20S)-methoxy-(60S)-[10-dicyclohexylsulphamoyl-(2R)-isobornyl]-carbonyl-50 ,60-
dihydro-2H-pyran 9 and (20R)-methoxy-(60R)-[10-dicyclohexylsulphamoyl-(2R)-isobornyl]-carbonyl-
50,60-dihydro-2H-pyran 11
A solution of diene (1 mL, 10 mmol), heterodienophile (0.2 g, 0.44 mmol) and Eu(fod)3 in CH2Cl2
(3 mL) was stirred. The reaction mixture was filtered through a short silica gel pad, then the filtrate was
evaporated to dryness and the oily residue was dissolved in MeOH. To this solution PPTS (0.1 g, 0.4
mmol) was added. The cis–trans isomerization was carried out at room temperature over a period of 1
h. The solvent was evaporated and the residue was treated with Et2O (5 mL). The precipitated inorganic
salts were filtered off and the crude reaction mixture was purified by flash chromatography (hexane:ethyl
acetate, 9:1) to afford the pure products 9 and 11.
Diastereoisomer 9. Mp: 172–173°C; [α]20 −39.2 (c 0.85, CHCl3); IR (KBr) νmax=3441, 2932, 2855,
D
1
1729, 1691, 1399, 1324, 1289, 1143, 1110, 1051, 981, 893, 820, 773, 719, 645, 575, 525 cm−1; H
NMR (500 MHz, CDCl3): δ 6.1–5.5 (m, 1H, CH_C), 5.8–5.7 (m, 1H, C_CH), 5.05 (dd, J=7.7, 3.0
Hz, 1H, OCHC_O), 4.95 (m, 1H, OCHOCH3), 4.47 (dd, J=10.1, 5.5 Hz, 1H, CH2CHO), 3.43 (s, 3H,
OCH3), 3.4–3.2 (m, 3H, CHSO2 and 2×CHN), 2.65 (1/2ABq, J=13.3 Hz, 1H, CH0SO2), 2.4–2.3 (m,
2H, CH2CH_C), 2.1–1.0 (m, 27H, 13×CH2 and CH), 0.99 (s, 3H, CH3), 0.89 (s, 3H, CH3); 13C NMR
(125 MHz, CDCl3): δ 169.4 (C_O), 127.7 (C_CH), 125.8 (C_CH), 96.0 (OCHOMe), 65.5 (CHO),
57.5 (CHN), 55.5 (OCHC_O), 53.6 (CH2SO2), 49.5 (C), 49.1 (C), 44.5 (CH), 44.4 (CH), 39.6 (CH2),
32.9 (CH2), 32.8 (CH2), 30.1 (CH2), 27.5 (CH2), 26.9 (CH2), 26.4 (CH2), 25.2 (CH2), 20.4 (CH3), 20.0
(CH3); m/z (EIMS): 537 (M+) (9.4), 505 (4.6), 494 (1.1), 442 (1.1), 380 (56), 316 (4), 298 (51), 292
(100), 254 (9), 244 (34), 228 (31), 180 (50), 157 (12), 135 (80), 111, (91), 93 (24), 81 (30), 55 (25); m/z
(EIHR) calcd for C29H47NO6S (M+): 537.3124; found: 537.31204.
Diastereoisomer 11. Mp: 163–164°C; [α]20 −32.9 (c 1.1, CHCl3); IR (KBr) νmax=3475, 2931, 2855,
D
1748, 1447, 1402, 1322, 1242, 1142, 1109, 1047, 980, 894, 854, 772, 717, 644, 579, 525 cm−1; 1H NMR
(500 MHz, CDCl3): δ 6.1–6.0 (m, 1H, CH_C), 5.8–5.6 (m, 1H, C_CH), 5.2–5.1 (m, 1H, OCHOCH3),
5.07 (dd, J=7.8, 2.9 Hz, 1H, OCHC_O), 3.49 (s, 3H, OCH3), 3.5–3.2 (m, 3H, CHSO2 and 2×CHN), 2.70
(1/2ABq, J=13.4 Hz, 1H, CH0SO2), 2.6–2.5 (m, 1H, CHCH_C), 2.4–2.3 (m, 1H, CH0CH_C), 2.05–1.07
(m, 27H, 13×CH2 and CH), 1.05 (s, 3H, CH3), 0.89 (s, 3H, CH3); 13C NMR (125 MHz, CDCl3): δ 168.9
(C_O), 128.4 (C_CH), 126.9 (C_CH), 98.3 (OCHOMe), 70.7 (CHO), 57.6 (CHN), 55.1 (OCHC_O),
53.8 (CH2SO2), 49.6 (C), 49.2 (C), 44.4 (CH), 39.6 (CH), 39.4 (CH2), 33.0 (CH2), 32.8 (CH2), 32.7
(CH2), 32.6 (CH2), 30.4 (CH2), 30.3 (CH2), 27.0 (CH2), 26.9 (CH2), 26.5 (CH2), 26.48 (CH2), 26.4
(CH2), 25.2 (CH2), 25.1 (CH2), 20.4 (CH3), 20.0 (CH3); m/z (EIMS): 537 (M+) (19), 505 (10), 380 (51),
298 (60), 292 (57), 244 (44), 228 (34), 180 (52), 157 (18), 135 (100), 111 (90), 93 (30), 81 (35), 55 (26);
m/z (EIHR) calcd for C29H47NO6S: 537.31240; found: 537.31257.
3.5. Preparation of 10-dicyclohexylsulphamoyl-(2R)-isobornyl-20 (S)-hydroxy-pent-4-enoate 12 and
10-dicyclohexylsulphamoyl-(2R)-isobornyl-2(R)-hydroxy-pent-4-enoate 13
A solution of glyoxylate 6 (117 mg, 0.258 mmol) in dry THF (5 mL) was cooled under argon (−78°C),
and then allylmagnesium chloride was added (2 M solution in THF, 0.2 mL, 0.4 mmol). The reaction was
stirred for 1 h, then poured into a saturated solution of NaCl. The reaction mixture was allowed to warm
up to room temperature. It was extracted with ether (3×30 mL). Flash chromatography (hexane:ethyl
acetate, 9:1) of the residue afforded a mixture of two diastereoisomers 12 and 13 (51 mg, 40%). The
asymmetric induction was assessed by 1H NMR analysis.

A. Czapla et al. / Tetrahedron: Asymmetry 10 (1999) 2101–2111
2109
A mixture of diastereoisomers 12 and 13 1H NMR (500 MHz, CDCl3): δ 5.9–5.7 (m, 1H, CH_CH2
for 12 and 13), 5.3–5.1 (m, 2H, CH_CH2 for 12 and 13), 5.07 (dd, J=7.9, 3.2 Hz, 0.5H, CHOH for
12), 5.01 (dd, J=7.8, 3.0 Hz, 0.5H, CHOH for 13), 4.2–4.1 (m, 1H, CHO for 12 and 13), 3.3–3.1 (m,
3H, CHSO2 and 2×CHN for 12 and 13), 3.0 (bs, 0.5H, OH for 12), 2.84 (bs, 0.5H, OH for 13), 2.67
(1/2ABq, J=13.3 Hz, 0.5H, CHSO2 for 12), 2.66 (1/2ABq, J=13.3 Hz, 0.5H, CHSO2, for 13), 2.6–2.3 (m,
2H, CH2 for 12 and 13), 2.1–1.0 (m, 27H, 13×CH2 and CH for 12 and 13), 1.00 (s, 1.5H, CH3 for 13),
0.99 (s, 1.5H, CH3 for 12), 0.89 (s, 1.5H, CH3 for 13), 0.88 (s, 1.5H, CH3 for 12); 13C NMR (125 MHz,
CDCl3): δ 173.2 (C_O for 12), 172.6 (C_O for 13), 132.8 (_CH for 13), 132.5 (_CH for 12), 119.1
(_CH2 for 13), 118.4 (_CH2 for 12), 80.1 (CHO for 12), 79.9 (CHO for 13), 57.6 (CHN for 12), 57.5
(CHN for 13), 54.1 (CH2SO2 for 13), 53.9 (CH2SO2 for 12), 49.7 (C for 13), 49.6 (C for 12), 49.3 (C
for 13), 49.2 (C for 12), 44.5 (CH for 12), 44.4 (CH for 13), 39.7 (CH2), 39.4 (CH2), 38.9 (CH2), 38.1
(CH2), 33.3 (CH2), 32.9 (CH2), 32.8 (CH2), 32.4 (CH2), 30.8 (CH2), 30.3 (CH2), 27.0 (CH2), 27.0 (CH2),
26.5 (CH2), 26.5 (CH2), 26.4 (CH2), 26.4 (CH2), 25.2 (CH2), 25.2 (CH2), 20.4 (CH3), 20.3 (CH3), 20.1
(CH3), 20.0 (CH3); m/z (HRLSIMS) calcd for (M+Na)+ C27H45N1O5S1Na: 518.2916; found: 518.2902.
When using allyltrimethylsilane, the solution of glyoxylate 6 (78 mg, 0.17 mmol) in CH2Cl2 (5 mL) was
cooled under argon to −78°C. The Lewis acid was then added, followed by the allyltrimethylsilane (71
µL, 0.45 mmol). The workup procedure was the same as above.
3.6. Preparation of 10-dicyclohexylsulphamoyl-(2S)-isobornyl-20 (S)-acetoxy-pent-4-enoate 14 and
10-dicyclohexylsulphamoyl-(2R)-isobornyl-20 (S)-acetoxy-pent-4-enoate 15
The mixture of diastereoisomers 13 and 14 (558 mg, 1.13 mmol) was dissolved in 4 mL of pyridine
and then treated with acetic anhydride (4 mL). The solution was stirred for 1 h at room temperature.
The post-reaction mixture was washed with aqueous CuSO4 (3×50 mL), and finally diluted with Et2O
(2×70 mL) and dried (MgSO4). After evaporation in vacuo, the residue (97%) was subjected to flash
chromatography (hexane:ethyl acetate, 9:1) in order to separate the two diastereoisomers.
Diastereoisomer 14 (oil). [α]20 −39.7 (c 1, CHCl3); IR (KBr) νmax=3464, 2936, 2857, 1746, 1644
D
cm−1; 1H NMR (200 MHz, CDCl3): δ 5.9–5.6 (m, 1H, CH_CH2), 5.2–5.0 (m, 3H, CH_CH2 and CHO),
5.0–4.9 (m, 1H, CHOAc), 3.4–3.1 (m, 3H, CHSO2 and 2×CHN), 2.9–2.5 (m, 3H, CH0SO2 and CH2),
2.1 (s, 3H, O_CCH3), 2.1–1.0 (m, 27H, 13×CH2 and CH), 0.93 (s, 3H, CH3), 0.87 (s, 3H, CH3); 13C
NMR (200 MHz, CDCl3): δ 169.9 (C_O), 168.0 (C_O), 132.2 (_CH), 118.4 (_CH2), 79.7 (CH–O),
71.7 (CHAc), 57.4 (CHN), 53.5 (CH2SO2), 49.3 (C), 49.0 (C), 44.3 (CH), 39.2 (CH2), 35.3 (CH2), 32.9
(CH2), 32.5 (CH2), 30.3 (CH2), 26.9 (CH2), 26.3 (CH2), 25.0 (CH2), 20.5 (CH3), 20.3 (CH3), 19.6 (CH3);
m/z (LSIMS, NBA) 560 (M+Na)+ (15), 538 (M+H)+ (10), 380 (80), 298 (15), 228 (30), 149 (37), 135
(100), 133 (20); m/z (HRLSIMS) calcd for C29H47NO6SNa: 560.3018; found: 560.3018.
Diastereoisomer 15. Mp: 127°C (from methanol/hexane); [α]20 −19.0 (c 1.6, CHCl3); IR (KBr)
D
ν
max=3484, 2856, 1757, 1746, 1644 cm−1; 1H NMR (500 MHz, CDCl3): δ 6.0–5.7 (m, 1H, CH_CH2),
5.3–5.0 (m, 3H, CH_CH2 and CHO), 5.1–4.9 (m, 1H, CHOAc), 3.4–3.1 (m, 3H, CHSO2 and 2×CHN),
2.8–2.5 (m, 3H, CH0SO2 and CH2), 2.13 (s, 3H, O_CCH3), 2.0–1.0 (m, 27H, 13×CH2 and CH), 1.04 (s,
3H, CH3), 0.9 (s, 3H, CH3); 13C NMR (125 MHz, CDCl3): δ 170.4 (C_O), 168.1 (C_O), 132.4 (_CH),
118.5 (_CH2), 79.6 (CH–O), 71.5 (CHAc), 57.5 (CHN), 53.8 (CH2SO2), 49.5 (C), 49.2 (C), 44.3 (CH),
39.4 (CH2), 34.9 (CH2), 33.2 (CH2), 32.4 (CH2), 30.5 (CH2), 27.0 (CH2), 26.4 (CH2), 25.2 (CH2), 20.6
(CH3), 20.4 (CH3), 19.9 (CH3); m/z (EIMS) 537 (190) M+, 298 (100), 244 (75), 180 (37), 135 (37); m/z
(EIHR) calcd for C29H47NO6S: 537.3124; found: 537.3134.

2110
A. Czapla et al. / Tetrahedron: Asymmetry 10 (1999) 2101–2111
Table 4
Crystal data and structural refinement for compounds 11 and 15
3.7. X-Ray structure determination of compounds 11 and 15
Suitable crystals were grown from ethyl acetate/hexane 11 and methanol/hexane 15 solutions. The
measurements were done on a Nonius MACH3 diffractometer with Express package. No absorption
correction was applied. Table 4 shows details of data collection and structure refinement. Positions for
the hydrogen atoms were calculated and refined in the riding mode with isotropic thermal parameters
20% higher than that of the parent atoms.
In the case of compound 11, both disorder and large thermal vibrations were detected at the newly
generated asymmetric centres at carbons C26 and C30. Therefore, special attention has been paid during
the structural elucidation and refinement processes. Careful refinement of different structural models
taking into account both geometrical parameters and the relative electron densities of particular peaks in
electron density maps brought us to the model shown in Fig. 1. The six-membered sugar ring has two
locations (occupancy factors 0.7:0.3) obtained by parallel displacement of all atoms. After completing
the ring with 0.7 population of atoms, the highest peak on the difference electron density maps was
assigned to the O5a atom, which confirms the fact that rotation about O3–C25 was not observed and the
compound is a single isomer.
The structures were solved by the SHELXS8620 and refined by SHELXL9321 programs. Crystallo-

A. Czapla et al. / Tetrahedron: Asymmetry 10 (1999) 2101–2111
2111
graphic data have been deposited with the Cambridge Crystallographic Data Centre, University Chemical
Laboratory, 12 Union Road, Cambridge CB2 1EZ, England, as supplementary publication No. CCDC
114 322 for compound 11 and No. CCDC 114 321 for compound 15.
References
1. Bauer, T.; Chapuis, C.; Kozak, J.; Jurczak, J. Helv. Chim. Acta 1989, 72, 482.
2. Bauer, T.; Jezewski, A.; Chapuis, C.; Jurczak, J. Tetrahedron: Asymmetry 1996, 7, 1385.
3. Oppolzer, W.; Chapuis, C.; Bernadinelli, G. J. Helv. Chim. Acta 1984, 67, 1397.
4. Bauer, T.; Chapuis, C.; Jezewski, A.; Kozak, J.; Jurczak, J. Tetrahedron: Asymmetry 1996, 7, 1391.
5. Bauer, T.; Jezewski, A.; Jurczak, J. Tetrahedron: Asymmetry 1996, 7, 1405.
6. Bauer, T. Tetrahedron 1997, 53, 4763.
7. Jezewski, A.; Chajewska, K.; Wielogorski, Z.; Jurczak, J. Tetrahedron: Asymmetry 1997, 8, 1741.
8. Bauer, T. Tetrahedron: Asymmetry 1996, 7, 981.
9. Kiegiel, K.; Prokopowicz, P.; Jurczak, J. Synth. Commun., in press.
10. Oppolzer, W.; Chapuis, C.; Bernadinelli, G. J. Tetrahedron Lett. 1984, 25, 5885.
11. Oppolzer, W.; Dudfield, P. Tetrahedron Lett. 1985, 26, 5037.
12. Shida, N.; Kabuto, C.; Niwa, T.; Ebata, T.; Yamamoto, Y. J. Org. Chem. 1994, 59, 4068.
13. Jurczak, J. Polish J. Chem. 1979, 53, 2539.
14. Bednarski, M.; Danishefsky, S. J. Am. Chem. Soc. 1983, 105, 3716.
15. Jurczak, J.; Golebiowski, A.; Bauer, T. Synthesis 1985, 928.
16. Jurczak, J.; Bauer, T.; Golebiowski, A. Bull. Pol. Acad. Chem. 1985, 33, 397.
17. Chapuis, C. PhD Thesis, University of Geneva, 1984, No. 2144.
18. Still, W. C.; Kahn, M.; Mitra, A. J. Org. Chem. 1978, 43, 2939.
19. Montagna, A. E.; Hirsch, D. H. US Patent 1959, 2905772; Chem. Abstr. 1960, 54, 2168.
20. Sheldrick, G. M. Program for Solution of Crystal Structures, University of Göttingen, Germany, 1985.
21. Sheldrick, G. M. Program for Refinement of Crystal Structures, University of Göttingen, Germany, 1993.