Asymmetric reaction of simple nitro compounds with chiral 1,3-oxazolidin-2-ones

Article abstract of DOI:10.1002/hlca.200490156

The chiral oxazolidinone 1 (=[(3aS,6R,7aR)-tetrahydro-8,8-dimethyl-2-oxo4H- 3a,6-methano-1,3-benzoxazol-3-yl](oxo)acetaldehyde) was found to react stereoselectively with simple nitro compounds in the presence of Al ₂O₃ or Bu₄

Full text of DOI:10.1002/hlca.200490156

1724
Helvetica Chimica Acta Vol. 87 (2004)
Asymmetric Reaction of Simple Nitro Compounds with Chiral
1,3-Oxazolidin-2-ones
by Iwona Kudybaa), Jerzy Raczkoa)b), and Janusz Jurczak*a)c)
a) Institute of Organic Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, 01-224 Warsaw, Poland
b) ZD CHEMIPAN, Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52,
01-224 Warsaw, Poland
c) Department of Chemistry, Warsaw University, Pasteura 1, 02-093 Warsaw, Poland
(phone: ‡48-22-8230944; fax: ‡48-22-8230944; e-mail: jurczak@icho.edu.pl)
Dedicated to Dr. G¸nther Ohloff on the occasion of his 80th birthday
The chiral oxazolidinone 1 (ˆ [(3aS,6R,7aR)-tetrahydro-8,8-dimethyl-2-oxo-4H-3a,6-methano-1,3-benzox-
azol-3-yl](oxo)acetaldehyde) was found to react stereoselectively with simple nitro compounds in the presence
of Al2O3 or Bu4NF ¥ 3 H2O (TBAF) as catalysts, affording the diastereoisomeric nitro alcohols 3 6 with good
asymmetric induction. When Al2O3 was used, the (S)-configuration at the center bearing the OH group was
generated, with the relative syn-configuration for the major diastereoisomers. In the case of the nitro-aldol
reaction catalyzed by TBAF, an opposite asymmetric induction was found for two nitro compounds. In contrast
to 1, compound 12 (ˆ((4R,5S)-4-methyl-2-oxo-5-phenyl-1,3-oxazolidin-3-yl)(oxo)acetaldehyde), a derivative
of Evans auxiliary, gave rise to poor asymmetric induction in Henry reactions.
Introduction. The nitro-aldol addition reaction is one of the basic methods for the
construction of CÀC bonds [1]. We have recently presented stereoselective reactions of
N-glyoxyloyl-(2R)-bornane-10,2-sultam and (1R)-8-phenylmenthyl glyoxylate with
simple nitro compounds, reactions that proceed with high asymmetric induction and
chemical yields [2][3]. This methodology has been applied in the efficient syntheses of
¾
two biologically important compounds: bestatin and the side chain of Taxotere [4]. In
the present paper, we would like to demonstrate extension of our investigations on the
diastereoselective Henry reaction of nitro compounds with two new glyoximides
derived from −7,7-dimethylnorbornane-(1S,2R)-oxazolidinone× [5], and (4R,5S)-4-
methyl-5-phenyl-1,3-oxazolidin-2-one [6].
Results and Discussion. The reaction of −N-glyoxyloyl-7,7-dimethylnorbornane-
(1S,2R)-oxazolidinone×1) (1) with nitro compounds of type 2 generally afforded the
nitro alcohols 3 6 (Scheme 1). In the case of the reaction of nitromethane (2a), carried
out in the presence of neutral Al2O3 (Method A1; Table 1) or tetrabutylammonium
fluoride trihydrate (TBAF ¥ 3 H2O; Method B) as catalysts, the diastereoisomeric nitro
alcohols 3a and 5a were obtained in yields of 93 and 87%, respectively (Table 1,
Entries 1 and 2). As far as the stereochemical outcome is concerned, we observed the
1
)
Systematic name: ((3aS,6R,7aR)-tetrahydro-8,8-dimethyl-2-oxo-4H-3a,6-methano-1,3-benzoxazol-3-
yl)(oxo)acetaldehyde.

Helvetica Chimica Acta Vol. 87 (2004)
1725
Scheme 1
formation of nitro alcohols with fair diastereoselectivities (28% and 72% de, resp.), as
shown in Table 1. Surprisingly, in the reaction catalyzed by TBAF ¥ 3 H2O, we noticed
inversion of asymmetric induction.
We extended our studies of the reaction between 1 and nitro compounds, and tested
five more substrates: 1-nitrohexane (2b), (nitromethyl)benzene (2c), 1,1-diethoxy-2-
nitroethane (2d), ethyl nitroacetate (2e), and (2-nitroethyl)benzene (2f). The results
of these investigations are summarized in Table 1. Generally, all these transformations
Table 1. Synthesis of Nitro Alcohols 3 6. For details, see the Exper. Part. and Scheme 1.
Entry
Nitro compound
Methoda)
Time [h]
Yieldb) [%]
drc)
3/4/5/6
1
2
3
4
5
6
7
8
9
10
11
12
13
14
2a
2a
2b
2b
2c
2c
2d
2d
2e
2e
2f
2f
2f
2f
A1
B
A1
B
A1
B
A1
B
A1
B
A1
A2
A3
B
2
1
2
1
2
1
2
1
2
1
2.5
1
36
12
93
87
88
86
92
92
88
94
86
91
88
87
72
80
64 : 36d)
14 : 86d)
45 : 25 : 21 : 9
4 : 2 : 35 : 59
70 : 17: 10 : 3
55 : 19 : 11 : 15
67: 17 : 11 : 5
66 : 10 : 21 : 3
29 : 27: 23 : 21
35 : 24 : 21 : 20
34 : 28 : 21 : 17
42 : 31 : 15 : 12
41 : 39 : 10 : 10
48 : 41 : 6 : 5
a) A1: Al2O3, r.t.; A2: activated Al2O3, r.t.; A3: activated Al2O3, À 208; B: TBAF ¥ 3 H2O, À 788. b) Isolated
yield of diastereoisomeric mixtures. c) Diastereoisomer ratio; determined by both HPLC and 1H-NMR.
d) Compounds 3a and 4a, as well as 5a and 6a, respectively, are identical.

1726
Helvetica Chimica Acta Vol. 87 (2004)
proceeded in high yields. Activation of Al2O3 by heating for 2 h at reduced pressure was
not necessary, but it reduced the reaction time (Table 1, Entries 11 vs. 12). The nitro
alcohols were formed with modest diastereoselectivities. In the case of processes
catalyzed by TBAF ¥ 3 H2O (Method B), an inversion of asymmetric induction was
observed only for the reaction between 1 and 2b (Entry 4).
The configurations of the diastereoisomeric nitro alcohols were assigned by means
of various analytical and spectral methods, including chemical correlation, X-ray
crystal-structure analysis, and NOE (nuclear Overhauser effect) experiments. The
configuration of the major diastereoisomer 5a (obtained from 1 and 2a via Method B)
was established on the basis of X-ray analysis, showing (2'R)-configuration at the newly
formed stereogenic center (Fig. 1).
Fig. 1. X-Ray crystal structure of 5a
The stereoselectivity of the reaction was much more complex to determine for the
diastereoisomeric products of type b f. The (2S,3R)- and the relative syn-config-
urations of the major product 3b (Method A1; Table 1, Entry 3) were established on the
basis of comparison of NMR spectra and optical rotations of the degradation product 3-
nitrooctan-1,2-diol (7), obtained via two separate reductive cleavages of the chiral
auxiliaries from the adduct 3b or the sultam adduct 8, respectively, of known
configuration (Scheme 2) [2].
Scheme 2
The structure and configuration of the major adduct 3c (Table 1, Entry 5) was
determined by X-ray crystal-structure analysis (Fig. 2). The configuration was found to
be (2'S,3'R), with relative syn-configuration of the OH and NO2 groups. Compound 5c

Helvetica Chimica Acta Vol. 87 (2004)
1727
Fig. 2. X-Ray crystal structure of 3c
Fig. 3. X-Ray crystal structure of 5c
was also identified via X-ray-analysis (Fig. 3). Here, the same syn relation was
observed, but the opposite absolute configuration, i.e., (2'R,3'S).
The absolute configuration of 3f (Table 1, Entry 12) was confirmed by chemical
correlation with the known, optically pure acid 9 [4][7], which was obtained from 3f in
a four-step sequence in 60% overall yield (Scheme 3). Both the optical rotation and
NMR spectra of the −degradation× product 9 were identical with those of a sample
synthesized from the menthol derivative 10, thus corroborating the absolute config-
uration of 3f.
Next, we turned our attention to Evans chiral auxiliary 11, a highly efficient catalyst
in various diastereoselective organic reactions [6], and converted it into −N-glyoxyloyl-

1728
Helvetica Chimica Acta Vol. 87 (2004)
Scheme 3
a) H2, Raney-Ni, MeOH. b) Boc2O. c) DMP, p-TsOH. d) LiOH, H2O2.
(4R)-methyl-(5S)-phenyloxazolidinone×2) (12; Scheme 4). Compound 12, which is not
known in the literature, was then tested as an auxiliary in asymmetric Henry reactions.
However, only moderate yields were obtained, even at prolonged reaction times
(Table 2); and the same was true with compound 1. The only exception was the reaction
between 12 and 2e (Table 2, Entries 9 and 10), which gave a mixture of nitro alcohols in
more than 90% yield.
Scheme 4
a) Crotonoyl chloride, NaH. b) OsO4/NaIO4 or O3. c) 808, 0.2 mm Hg. d) Al2O3 or TBAF ¥ 3 H2O.
‡
Table 2. Synthesis of the Nitro Alcohols 13a e (see Scheme 4). TBAF ˆ (Bu4N FÀ ) ¥ 3 H2O.
Entry
Nitro compound
Methoda)
Time [h]
Product
Yieldb) [%]
drc)
1
2
3
4
5
6
7
8
9
2a
A
B
A
B
A
B
A
B
A
B
24
24
120
24
24
24
100
24
4
13a
62
50
29
57
63
74
10
16
95
90
56 : 44
65 : 35
2b
2c
2d
2e
13b
13c
13d
13e
50 : 25 : 20 : 5
26 : 9 : 48 : 17
36 : 27: 25 : 12
12 : 11 : 57: 20
35 : 34 : 29 : 2
47: 36 : 10 : 7
28 : 26 : 25 : 21
26 : 32 : 20 : 22
10
1
a) A: Al2O3, r.t.; B: TBAF ¥ 3 H2O, À 788. b) Isolated yield of diastereoisomeric mixture. c) Diastereoisomer
1
ratio; determined by H-NMR.
2
)
Systematic name: ((4R,5S)-4-methyl-2-oxo-5-phenyl-1,3-oxazolidin-3-yl)(oxo)acetaldehyde.

Helvetica Chimica Acta Vol. 87 (2004)
1729
Contrary to the reactions of glyoximide 1, the diastereoselectivities of the above
reactions with auxiliary 12 were unexpectedly poor. Considering this, we did not carry
out the reactions in the presence of activated catalysts, because, although improving
chemical yields, this lowered the degree of asymmetric induction. Moreover, the nitro
alcohols were formed as inseparable mixtures of diastereoisomers, discouraging our
efforts for assignment of configuration. Only for 13a (prepared via Method B) we
attempted to assign the configurations. Reduction of 13a yielded 3-nitropropane-1,2-
diol, whose optical rotation was compared with that of an authentic sample of known
(2S)-configuration, with [a]2D0 ˆ À6.7 (c ˆ 0.99, CHCl3) [2]. The optical rotation
measured for the degradation product was [a]2D0 ˆ 2.2 (c ˆ 1.8, CHCl3), which indicated
(2R)-configuration of the major diastereoisomer, i.e., the same as in the case of the 7,7-
dimethylnorbornane-derived adduct.
Conclusions. We have demonstrated that the chiral auxiliary 1 is an alternative to
existing catalysts for the preparation of optically pure nitro alcohols, which are
important starting materials for various natural products. Compounds 3 6 were
obtained in 72 94% overall yield, with medium-to-good stereoselectivities. The new
method further benefits from the fact that 1 can be recovered in 70 85% yield by
means of hydrolysis or reduction.
Experimental Part
General. All reactions were carried out under Ar atmosphere in anh. solvents dried according to standard
methods. Column chromatography (CC) was performed on Kieselgel 60 (200 400 mesh; Merck). Thin-layer
chromatography (TLC) was performed on Kieselgel 60 F254 on aluminum plates (Merck); visualization with a
soln. of MoO3 and Ce2(SO4)3 in 15% aq. H2SO4. M.p.: Kofler hot-stage apparatus; uncorrected. Optical
rotations: JASCO DIP-360 polarimeter, thermally jacketed 10-cm cell. IR Spectra: Perkin-Elmer-1640 FT-IR
apparatus; in cmÀ1. 1H- and 13C-NMR Spectra: Bruker AM and Varian Gemini spectrometers; chemical shifts d
(in ppm) rel. to residual CHCl3 solvent signals; coupling constants J in Hz. Mass spectra: AMD-604 Intectra
mass spectrometer; in m/z.
General Procedure for Al2O3-Catalyzed Nitro-Aldol Reactions (Methods A1 A3; see also Table 1).
Compound 1 (1 mmol) and a nitro compound 2 (2 mmol) were added to a soln. of regular (Method A1) or
activated3) (Methods A2 or A3) Al2O3 (2 mmol) in THF (5 ml). The mixture was stirred at r.t. or at À 208
(Method A3), respectively, under Ar. The reaction was allowed to go to completion (TLC). The mixture was
filtered and evaporated, and the products were purified by FC (hexane/AcOEt 9 :1 ! 6 :4).
General Procedure for TBAF-Catalyzed Nitro-Aldol Reactions (Method B). Tetrabutylammonium fluoride
trihydrate (TBAF ¥ 3 H2O; 0.5 mmol) was added to a soln. of 1 (1 mmol) in anh. THF (5 ml) at À 788 under Ar
atmosphere, followed by addition of a nitro compound 2 (2 mmol). The reaction was allowed to go to
completion (TLC), and was then quenched by addition of brine. The mixture was extracted with AcOEt, the
combined org. extracts were dried (MgSO4) and evaporated, and the products were purified by FC (hexane/
AcOEt 9 :1 ! 6 :4).
(3aS,6R,7aR)-Tetrahydro-3-[(2R)-2-hydroxy-3-nitropropanoyl]-8,8-dimethyl-3a,6-methano-1,3-benzoxa-
zol-2(4H)-one (5a). Method B. Isolated yield after crystallization: 58%. M.p. 2068 (MeOH). Rf (hexane/AcOEt
7:3) 0.50. [a]2D0 ˆ ‡68.8 (c ˆ 0.96, CHCl3). IR (KBr): 3482, 2970, 1784, 1710, 1550, 1379, 1322, 1176, 1077, 1055,
763. 1H-NMR (500 MHz, CDCl3): 5.46 (dd, J(2',3'A) ˆ 4.6, J(2',3'B) ˆ 4.8, HÀC(2')); 4.86 (dd, J ˆ 13.8,
J(2',3'A) ˆ 4.6, HAÀC(3')); 4.90 (dd, J ˆ 13.8, J(2',3'B) ˆ 4.8, HBÀC(3')); 4.41 (dd, J(7a,7A) ˆ 4.2, J(7a,7B) ˆ
8.2, HÀC(7a)); 2.92 2.86 (m, HAÀC(4)); 2.35 2.25 (m, HAÀC(7)); 1.94 1.82 (m, HAÀC(5), HBÀC(7),
HÀC(6)); 1.40 1.30 (m, HBÀC(5)); 1.17, 1.05 (2s, 2 MeÀC(8)); 1.00 0.95 (m, HBÀC(4)). 13C-NMR
(125 MHz, CDCl3): 171.0 (C(1')); 155.3 (C(2)); 86.3 (C(7a)); 76.6 (C(3')); 72.8 (C(3a)); 68.4 (C(2')); 48.3
3
)
Activation was performed by heating for 2 h at 1208/0.2 Torr.

1730
Helvetica Chimica Acta Vol. 87 (2004)
(C(8)); 42.2 (C(6)); 34.6 (C(7)); 25.7 (C(5)); 24.0 (C(4)); 21.4, 18.5 (2 MeÀC(8)). HR-ESI-MS: 299.1228 ([M ‡
‡
‡
H] , C13H19N6O2 ; calc. 299.1238). Anal. calc. for C13H18N2O6: C 52.34, H 6.08, N 9.39; found: C 52.14, H 6.33, N
9.20.
(3aS,6R,7aR)-Tetrahydro-3-[(2S)-2-hydroxy-3-nitropropanoyl]-8,8-dimethyl-3a,6-methano-1,3-benzoxa-
zol-2(4H)-one (3a). Rf (hexane/AcOEt 7:3) 0.50. 1H-NMR (500 MHz, CDCl3; selected signals from differential
NMR): 5.47 (dd, J(2',3'A) ˆ 5.0, J(2',3'B) ˆ 4.5, HÀC(2')); 4.94 (dd, J ˆ 13.3, J(2',3'A) ˆ 5.0, HAÀC(3')); 4.90
(dd, J ˆ 13.3, J(2',3'B) ˆ 4.5, HBÀC(3')); 4.42 (dd, J(7a,7A) ˆ 4.2, J(7a,7B) ˆ 8.2, HÀC(7a)); 1.15, 1.08
(2s, 2 MeÀC(8)). 13C-NMR (125 MHz, CDCl3; selected signals): 169.8 (C(1')); 155.0 (C(2)); 86.2 (C(7a));
77.3 (C(3')); 72.9 (C(3a)); 68.8 (C(2')); 48.0 (C(8)); 43.1 (C(6)); 34.4 (C(7)); 25.8 (C(5)); 24.4 (C(4)); 20.8, 18.6
(2 MeÀC(8)).
(3aS,6R,7aR)-Tetrahydro-3-[(2S,3R)-2-hydroxy-3-nitrooctanoyl]-8,8-dimethyl-3a,6-methano-1,3-benzoxa-
zol-2(4H)-one (3b). Method B. Isolated yield after double CC: 28%. Rf (hexane/AcOEt 7:3) 0.60. [a]2D0 ˆ ‡27.5
(c ˆ 0.48; CHCl3). IR (film): 3476, 2960, 1783, 1708, 1552, 1372, 1323, 1176, 1078, 1023, 765. 1H-NMR (500 MHz,
CDCl3): 5.23 (dd, J(2',3') ˆ 8.8, J(2',OH) ˆ 2.4, HÀC(2')); 5.14 (ddd, J(2',3') ˆ 8.8, J(3',4'A) ˆ 2.4, J(3',4'B) ˆ
5.3, HÀC(3')); 4.40 (dd, J(7a,7A) ˆ 4.2, J(7a,7B) ˆ 8.1, HÀC(7a)); 3.10 2.90 (m, HAÀC(4)); 2.40 2.28
(m, HAÀC(7), CH2(4')); 2.13 1.80 (m, HAÀC(5), HBÀC(7), HÀC(6)); 1.50 1.25 (m, HBÀC(5), CH2(5'),
CH2(6'), CH2(7')); 1.20 1.05 (m, HBÀC(4)); 1.16, 0.92 (2s, 2 MeÀC(8)); 0.94 0.86 (m, Me(8')). 13C-NMR
(125 MHz, CDCl3): 172.1 (C(1')); 154.9 (C(2)); 88.9 (C(3')); 86.2 (C(7a)); 72.6 (C(3a)); 71.5 (C(2')); 48.5
(C(8)); 42.3 (C(6)); 34.7 (C(7)); 31.1 (C(4')); 29.5 (C(5')); 26.0 (C(5)); 25.9 (C(6')); 25.5 (C(4)); 22.1 (C(7'));
‡
‡
20.4, 18.7 (2 MeÀC(8)); 13.8 (Me(8')). HR-LSI-MS: 369.20158 ([M ‡ H] , C18H29N6O2 ; calc. 369.20256). Anal.
calc. for C18H28N2O6: C 58.68, H 7.66, N 7.60; found C 58.96, H 7.43, N 7.31.
(3aS,6R,7aR)-Tetrahydro-3-[(2S,3S)-2-hydroxy-3-nitrooctanoyl]-8,8-dimethyl-3a,6-methano-1,3-benzoxa-
zol-2(4H)-one (4b). 1H-NMR (500 MHz, CDCl3; selected signals): 5.38 (dd, J(2',3') ˆ 3.1, J(2',OH) ˆ 7.2,
HÀC(2')); 4.86 (ddd, J(2',3') ˆ 3.1, J(3',4'A) ˆ 8.6, J(3',4'B) ˆ 5.6, HÀC(3')); 4.43 (dd, J(7a,7A) ˆ 4.2,
J(7a,7B) ˆ 8.2, HÀC(7a)); 3.80 (d, J(2',OH) ˆ 7.2, OH); 1.16, 1.05 (2s, 2 MeÀC(8)). 13C-NMR (125 MHz,
CDCl3; selected signals): 171.8 (C(1')); 155.0 (C(2)); 88.9 (C(3')); 86.2 (C(7a)); 72.8 (C(3a)); 71.6 (C(2')); 48.3
(C(8)); 42.5 (C(6)); 34.5 (C(7)); 31.1 (C(4')); 29.4 (C(5')); 25.7 (C(5)); 25.2 (C(6')); 24.7 (C(4)); 24.2 (C(7'));
21.4, 19.9 (2 MeÀC(8)); 13.8 (Me(8')).
(3aS,6R,7aR)-Tetrahydro-3-[(2R,3S)-2-hydroxy-3-nitrooctanoyl]-8,8-dimethyl-3a,6-methano-1,3-benzoxa-
zol-2(4H)-one (5b). 1H-NMR (500 MHz, CDCl3; selected signals): 5.22 (dd, J(2',3') ˆ 8.1, J(2',OH) ˆ 6.2,
HÀC(2')); 4.90 (dt, J(2',3') ˆ J(3',4'A) ˆ 8.1, J(3',4'B) ˆ 3.9, HÀC(3')); 4.46 (d, J(2',OH) ˆ 6.2, OH); 4.39
(dd, J(7a,7A) ˆ 4.2, J(7a,7B) ˆ 8.2, HÀC(7a)); 1.13, 1.04 (2s, 2 MeÀC(8)). 13C-NMR (125 MHz, CDCl3;
selected signals): 170.6 (C(1')); 155.9 (C(2)); 86.3 (C(3')); 85.9 (C(7a)); 72.6 (C(3a)); 70.4 (C(2')); 48.4 (C(8));
42.3 (C(6)); 34.6 (C(7)); 31.0 (C(4')); 29.6 (C(5')); 25.8 (C(5)); 25.1 (C(6')); 24.7 (C(4)); 24.2 (C(7')); 21.2, 18.9
(2 MeÀC(8)); 13.8 (Me(8')).
(3aS,6R,7aR)-Tetrahydro-3-[(2R,3R)-2-hydroxy-3-nitrooctanoyl]-8,8-dimethyl-3a,6-methano-1,3-benzoxa-
zol-2(4H)-one (6b). 1H-NMR (500 MHz, CDCl3; selected signals): 5.43 (t, J(2',3') ˆ J(2',OH) ˆ 6.7, HÀC(2'));
3.61 (d, J(2',OH) ˆ 6.7, OH).
(3aS,6R,7aR)-Tetrahydro-3-[(2S,3R)-2-hydroxy-3-nitro-3-phenylpropanoyl]-8,8-dimethyl-3a,6-methano-
1,3-benzoxazol-2(4H)-one (3c). Method A1. Yield after crystallization: 54%. M.p. 1988 (hexane/CH2Cl2). Rf
(hexane/AcOEt 7:3) 0.5. [a]2D0 ˆ ‡90 (c ˆ 1.05; CHCl3). IR (KBr): 3470, 2966, 1795, 1684, 1553, 1387, 1175,
1
1073, 759. H-NMR (500 MHz, CDCl3): 7.58 7.54 (m, 2 arom. H); 7.46 7.38 (m, 3 arom. H); 5.93 (t, J(2',3') ˆ
J(2',OH) ˆ 7.3, HÀC(2')); 5.81 (d, J(2',3') ˆ 7.3, HÀC(3')); 4.04 (d, J(2',OH) ˆ 7.3, OH); 4.04 (dd, J(7a,7A) ˆ
4.0, J(7a,7B) ˆ 8.2, HÀC(7a)); 2.68 (dt, J(4A,5A) ˆ 5.2, J(4A,5B) ˆ 4.0, HAÀC(4)); 2.25 (ddt, J(7a,7A) ˆ 4.0,
J(6,7A) ˆ 3.6, J(7A,7B) ˆ 13.9, HAÀC(7)); 2.23 1.95 (m, HAÀC(5)); 1.83 1.78 (m, HBÀC(7), HÀC(6)); 1.25
(ddd, J(4,5B) ˆ 5.2, J(5B,6) ˆ 9.3, J(5A,5B) ˆ 13.9, HBÀC(5)); 1.10 (2s, 2 MeÀC(8)); 0.99 0.93
(m, HBÀC(4)). 13C-NMR (125 MHz, CDCl3): 170.5 (C(1')); 154.9 (C(2)); 130.7, 130.2, 128.9, 128.8 (Ph); 92.3
(C(3')); 85.9 (C(7a)); 72.6 (C(3a)); 72.1 (C(2')); 48.2 (C(8)); 42.4 (C(6)); 34.5 (C(7)); 25.7 (C(5)); 24.5 (C(4));
‡
‡
21.3, 18.9 (2 MeÀC(8)). HR-ESI-MS: 369.20158 ([M ‡ Na] , C19H22N2NaO6 ; calc. 369.20256). Anal. calc. for
C19H22N2O6: C 60.94, H 5.92, N 7.48; found: C 60.96, H 5.98, N 7.35.
(3aS,6R,7aR)-Tetrahydro-3-[(2S,3S)-2-hydroxy-3-nitro-3-phenylpropanoy])-8,8-dimethyl-3a,6-methano-
1,3-benzoxazol-2(4H)-one (4c). Method A1. Yield after double CC: 10%. [a]2D0 ˆ ‡88 (c ˆ 1.12; CHCl3).
1H-NMR (500 MHz, CDCl3): 7.48 7.40 (m, 5 arom. H); 5.90 (d, J(2',3') ˆ 8.9, HÀC(3')); 5.66 (dd, J(2',3') ˆ 8.9,
J(2',OH) ˆ 6.2, HÀC(2')); 4.40 (dd, J(7a,7A) ˆ 4.2, J(7a,7B) ˆ 8.2, HÀC(7a)); 4.25 (d, J(2',OH) ˆ 6.2, OH);
2.81 (dt, J(4A,5A) ˆ 5.1, J(4A,5B) ˆ J(4A,4B) ˆ 12.0, HAÀC(4)); 2.25 (ddt, J(7a,7A) ˆ J(6,7A) ˆ 4.2,
J(7A,7B) ˆ 13.8, HAÀC(7)); 2.23 1.95 (m, HAÀC(5)); 1.90 (dd, J(7a,7B) ˆ J(6,7B) ˆ 8.2, J(7A,7B) ˆ 13.8,

Helvetica Chimica Acta Vol. 87 (2004)
1731
HBÀC(7)); 1.87 1.83 (m, HÀC(6)); 1.38 1.30 (m, HBÀC(5)); 1.23 1.16 (m, HBÀC(4)); 1.13, 1.04
(2s, 2 MeÀC(8)). 13C-NMR (125 MHz, CDCl3): 170.5 (C(1')); 155.8 (C(2)); 131.5; 130.1; 129.0; 128.4 (Ph);
88.2 (C(3')); 86.4 (C(7a)); 72.7 (C(3a)); 71.0 (C(2')); 48.4 (C(8)); 42.3 (C(6)); 34.7 (C(7)); 25.8 (C(5)); 25.0
(C(4)); 21.2, 18.9 (2 MeÀC(8)).
(3aS,6R,7aR)-Tetrahydro-3-[(2R,3S)-2-hydroxy-3-nitro-3-phenylpropanoyl]-8,8-dimethyl-3a,6-methano-
1,3-benzoxazol-2(4H)-one (5c). Yield after double CC: 6%. M.p. 1588. [a]2D0 ˆ ‡5 (c ˆ 1.65; CHCl3). 1H-NMR
(500 MHz, CDCl3): 7.66 7.62 (m, 2 arom. H); 7.45 7.38 (m, 3 arom. H); 6.03 (d, J(2',3') ˆ 5.7, HÀC(3')); 5.93
(dd, J(2',3') ˆ 5.7, J(2',OH) ˆ 8.3, HÀC(2')); 4.33 (dd, J(7a,7A) ˆ 4.3, J(7a,7B) ˆ 8.4, HÀC(7a)); 3.98
(d, J(2',OH) ˆ 8.3, OH); 2.99 2.90 (m, HAÀC(4)); 2.31 2.24 (m, HAÀC(7)); 2.04 1.96 (m, HAÀC(5)); 1.86
(dt, J(7a,7B) ˆ J(6,7B) ˆ 8.4, J(7A,7B) ˆ 13.7, HBÀC(7)); 1.82 1.79 (m, HÀC(6)); 1.34 1.29 (m, HBÀC(5));
1.17 1.00 (m, HBÀC(4)); 0.92, 0.88 (2s, 2 MeÀC(8)). 13C-NMR (125 MHz, CDCl3): 170.6 (C(1')); 155.0 (C(2));
131.1, 130.1, 129.2, 128.8 (Ph); 91.4 (C(3')); 85.8 (C(7a)); 72.6 (C(3a)); 72.3 (C(2')); 48.4 (C(8)); 42.2 (C(6));
34.7 (C(7)); 26.0 (C(5)); 25.8 (C(4)); 20.6, 18.7 (2 MeÀC(8)).
(3aS,6R,7aR)-Tetrahydro-3-[(2R,3R)-2-hydroxy-3-nitro-3-phenylpropanoyl]-8,8-dimethyl-3a,6-methano-
1,3-benzoxazol-2(4H)-one (6c). 1H-NMR (500 MHz, CDCl3 ; selected signals): 5.93 (dd, J(2',3') ˆ 8.1,
J(2',OH) ˆ 7.1, H ÀC(2')); 5.89 (d, J(2',3') ˆ 8.1, HÀC(3')); 4.38 (dd, J(7a,7B) ˆ 8.2, J(7a,7A) ˆ 4.2, HÀC(7a));
3.67 (d, J(2',OH) ˆ 7.1, OH ) .
(3aS,6R,7aR)-Tetrahydro-3-[(2S*,3S*)-4,4-diethoxy-2-hydroxy-3-nitrobutanoyl]-8,8-dimethyl-3a,6-meth-
ano-1,3-benzoxazol-2(4H)-one (3d). Only relative configurations (*) were assigned. Method A1. Isolated yield
after double CC: 42%. Rf (hexane/AcOEt 7:3) 0.5. [a]2D0 ˆ ‡34 (c ˆ 1.01; CHCl3). IR (film): 3474, 2977, 1783,
1703, 1555, 1372, 1328, 1176, 1117, 1076, 1025, 765. 1H-NMR (500 MHz, CDCl3): 5.75 (dd, J(2',3') ˆ 3.0,
J(2',OH) ˆ 8.3, HÀC(2')); 5.24 (d, J(3',4') ˆ 8.0, HÀC(4')); 4.96 (dd, J(2',3') ˆ 3.0, J(3',4') ˆ 8.0, HÀC(3')); 4.41
(dd, J(7a,7A) ˆ 4.2, J(7a,7B) ˆ 8.2, HÀC(7a)); 3.85 3.70 (m, 2 MeCH2O); 2.83 2.76 (m, HAÀC(4)); 2.35
2.28 (m, HAÀC(7)); 2.20 1.95 (m, HAÀC(5)); 1.94 1.84 (m, HBÀC(7), HÀC(6)); 1.38 1.29 (m, HBÀC(5));
1.23 1.18 (m, HBÀC(4)); 1.27, 1.17 (2t, J ˆ 7.0 each, 2 MeCH2O); 1.15, 1.04 (2s, MeÀC((8)). 13C-NMR
(125 MHz, CDCl3): 171.6 (C(1')); 154.6 (C(2)); 99.3 (C(4')); 88.9 (C(3')); 86.1 ((C(7a)); 72.8 ((C(3a)); 69.9
((C(2')); 64.5, 63.2 (2 MeCH2O); 48.2 (C(8)); 42.5 (C(6)); 34.5 (C(7)); 25.7 (C(5)); 24.6 (C(4)); 21.3, 19.0
‡
‡
(2 MeÀC(8)); 15.2, 14.9 (2 MeCH2O). HR-ESI-MS: 423.1738 ([M ‡ H] ; C18H28N2NaO8 ; calc. 423.1738).
Anal. calc. for C18H28N2O8: C 53.99, H 7.05, N 6.99; found: C 54.06, H 7.03, N 6.95.
(3aS,6R,7aR)-Tetrahydro-3-[(2S*,3R*)-4,4-diethoxy-2-hydroxy-3-nitrobutanoyl]-8,8-dimethyl-3a,6-meth-
ano-1,3-benzoxazol-2(4H)-one (4d). 1H-NMR (500 MHz, CDCl3; selected signals): 5.56 (dd, J(2',3') ˆ 3.7,
J(2',OH) ˆ 5.6, HÀC(2')); 5.15 (d, J(3',4') ˆ 6.5, HÀC(4')); 4.97 (dd, J(2',3') ˆ 3.7, J(3',4') ˆ 6.5, HÀC(3')); 4.38
(dd, J(7a,7A) ˆ 4.1, J(7a,7B) ˆ 8.2, HÀC(7a)). 13C-NMR (125 MHz, CDCl3; selected signals): 99.7 (C(4')); 87.3
(C(3')); 85.8 (C(7a)); 72.7 (C(3a)); 70.4 (C(2')); 48.3 (C(8)); 42.3 (C(6)); 34.7 (C(7)); 25.7 (C(5)); 24.9 (C(4));
21.5, 18.5 (2 MeÀC(8)).
(3aS,6R,7aR)-Tetrahydro-3-[(2R*,3R*)-4,4-diethoxy-2-hydroxy-3-nitrobutanoyl]-8,8-dimethyl-3a,6-meth-
ano-1,3-benzoxazol-2(4H)-one (5d). 1H-NMR (500 MHz, CDCl3; selected signals): 5.50 (d, J(3',4') ˆ 9.9,
HÀC(4')); 4.33 (dd, J(7a,7A) ˆ 4.1, J(7a,7B) ˆ 8.2, HÀC(7a)). 13C-NMR (125 MHz, CDCl3; selected signals):
88.4 (C(3')); 86.1 (C(7a)); 72.6 (C(3a)); 69.7 (C(2')); 48.5 (C(8)); 43.1 (C(6)); 34.3 (C(7)); 25.8 (C(5)); 24.0
(C(4)); 20.4, 18.4 (2 MeÀC(8)).
(3aS,6R,7aR)-Tetrahydro-3-[(2R*,3S*)-4,4-diethoxy-2-hydroxy-3-nitrobutanoyl]-8,8-dimethyl-3a,6-meth-
ano-1,3-benzoxazol-2(4H)-one (6d). 1H-NMR (500 MHz, CDCl3; selected signals): 5.68 (d, J(3',4') ˆ 8.4,
HÀC(4'); 4.24 (dd, J(7a,7A) ˆ 4.2, J(7a,7B) ˆ 8.4, HÀC(7a). 13C-NMR (125 MHz, CDCl3; selected signals):
85.6 (C(7a)); 73.5 (C(3a)); 47.9 (C(8)); 25.6 (C(5)); 25.1 (C(4)); 21.0, 18.9 (2 MeÀC(8)).
(3aS,6S,7aR)-Tetrahydro-3-[(2S*,3S*)-4-ethoxy-2-hydroxy-3-nitro-4-oxobutanoyl]-8,8-dimethyl-3a,6-meth-
ano-1,3-benzoxazol-2(4H)-one4) (3e). Inseparable mixture of nitroalcohols. Only relative configurations (*)
were assigned. Rf (hexane/AcOEt 7:3) 0.5. IR (film): 3468, 2956, 1794, 1683, 1550, 1381, 1174, 1070, 758.
1H-NMR (500 MHz, CDCl3): 5.68 (d, J(2',3') ˆ 8.0, HÀC(3')); 5.61 (dd, J(2',3') ˆ 8.0, J(2',OH) ˆ 6.4, HÀC(2'));
4.49 (d, J(2',OH) ˆ 6.4, OH); 4.43 4.38 (m, HÀC(7a)); 4.35 4.28 (m, MeCH2O); 2.90 2.80 (m, HAÀC(4));
2.35 2.28 (m, HAÀC(7)); 2.12 2.01 (m, HAÀC(5)); 1.97 1.80 (m, HBÀC(7), HÀC(6)); 1.40 1.26
(m, HBÀC(5), MeCH2O); 1.09, 1.04 (2s, 2 MeÀC(8)); 0.99 0.93 (m, HBÀC(4)). 13C-NMR (125 MHz, CDCl3):
169.9 (C(1')); 161.8 (C(4')); 155.5 (C(2)), 88.2 (C(3')); 86.0 (C(7a)); 72.5 (C(3a)); 70.0 (C(2')); 63.3 (MeCH2O);
4
)
Not fully systematic name. The benzoxazole nucleus was taken as the −parent× compound (to retain atom
numbering), although the COOEt group has higher priority.

1732
Helvetica Chimica Acta Vol. 87 (2004)
48.5 (C(8)); 42.2 (C(6)); 34.6 (C(7)); 25.6 (C(5)); 24.9 (C(4)); 20.8, 18.8 (2 MeÀC(8)); 13.7 (MeCH2O). HR-
‡
‡
ESI-MS: 393.1301 ([M ‡ Na] , C16H22N2NaO8 ; calc. 393.1268).
(3aS,6S,7aR)-Tetrahydro-3-[(2S*,3R*)-4-ethoxy-2-hydroxy-3-nitrobutanoyl]-8,8-dimethyl-3a,6-methano-
1,3-benzoxazol-2(4H)-one4) (4e). 1H-NMR (500 MHz, CDCl3 ; selected signals): 5.70 (d, J(2',3') ˆ 7.2,
HÀC(3')); 5.62 (dd, J(2',3') ˆ 7.2, J(2',OH) ˆ 5.8, HÀC(2')); 4.51 (d, J(2',OH) ˆ 5.8, OH); 1.16, 1.07
(2s, 2 MeÀC(8)). 13C-NMR (125 MHz, CDCl3; selected signals): 169.2 (C(1')); 162.2 (C(4')); 155.1 (C(2));
88.0 (C(3')); 86.3 (C(7a)); 72.6 (C(3a)); 69.8 (C(2')); 48.3 (C(8)); 42.3 (C(6)); 34.6 (C(7)); 25.7 (C(5)); 24.9
(C(4)); 21.1, 18.8 (2 MeÀC(8)); 13.6 (MeCH2O).
(3aS,6R,7aR)-Tetrahydro-3-[(2R*,3R*)-4-ethoxy-2-hydroxy-3-nitrobutanoyl]-8,8-dimethyl-3a,6-methano-
1,3-benzoxazol-2(4H)-one4) (5e). 1H-NMR (500 MHz, CDCl3 ; selected signals): 5.72 (d, J(2',3') ˆ 6.6,
HÀC(3')); 4.14 (d, J(2',OH) ˆ 7.9, OH); 1.13 1.11 (2s, 2 MeÀC(8)). 13C- NMR (125 MHz, CDCl3; selected
signals): 169.4 (C(1')); 161.9 (C(4')); 86.1 (C(7a)); 72.7 (C(3a)); 69.8 (C(2')); 48.3 (C(8)); 42.2 (C(6)); 34.5
(C(7)); 25.3 (C(5)); 21.2, 19.0 (2s, 2 MeÀC(8)); 13.7 (MeCH2O).
(3aS,6S,7aR)-Tetrahydro-3-[(2R*,3S*)-4-ethoxy-2-hydroxy-3-nitrobutanoyl]-8,8-dimethyl-3a,6-methano-
1,3-benzoxazol-2(4H)-one (6e). 1H-NMR (500 MHz, CDCl3; selected signals): 6.20 (d, J(2',3') ˆ 6.9, HÀC(3'));
1.06, 0.97 (2s, 2 MeÀC(8)). 13C-NMR (125 MHz, CDCl3; selected signals): 169.2 (C(1')); 162.2 (C(4')); 86.4
(C(7a)); 72.5 (C(3a)); 69.3 (C(2')); 48.5 (C(8)); 42.3 (C(6)); 34.5 (C(7)); 25.8 (C(5)); 20.9, 19.0 (2 MeÀC(8));
13.8 (MeCH2O).
(3aS,6R,7aR)-Tetrahydro-3-[(2S,3R)-2-hydroxy-3-nitro-4-phenylbutanoyl]-8,8-dimethyl-3a,6-methano-1,3-
benzoxazol-2(4H)-one (3f). Method A2. Yield after double CC: 22%. Rf (hexane/AcOEt 7:3) 0.5. [a]2D0 ˆ ‡29
(c ˆ 1.40; CHCl3). IR (film): 3474, 2963, 1781, 1708, 1553, 1372, 1321, 1176, 1078, 762, 700. 1H-NMR (500 MHz,
CDCl3): 7.33 7.23 (m, 5 arom. H); 5.45 (ddd, J(2',3') ˆ 2.2, J(3',4'B) ˆ 9.0, J(3',4'A) ˆ 5.8, HÀC(3')); 5.16 (dd,
J(2',3') ˆ 2.2, J(2',OH) ˆ 8.9, HÀC(2')); 4.35 (dd, J(7a,7A) ˆ 4.2, J(7a,7B) ˆ 8.2, HÀC(7a)); 4.33 (dd, J ˆ 14.4,
J(3',4'A) ˆ 5.8, HAÀC(4')); 3.69 (d, J(2',OH) ˆ 8.9, OH); 3.60 (dd, J ˆ 14.4, J(3',4B) ˆ 9.0, HBÀC(4')); 3.07
2.98 (m, HAÀC(4)); 2.32 (ddt, J(7a,7A) ˆ J(6,7A) ˆ 3.9, J(7A,7B) ˆ 13.7, HAÀC(7)); 2.21 2.02 (m, HAÀC(5));
1.88 (dd, J(7a,7B) ˆ J(6,7B) ˆ 8.2, J(7A,7B) ˆ 13.8, HBÀC(7)); 1.86 1.85 (m, HÀC(6)); 1.37 1.29
(m, HBÀC(5)); 1.17 1.10 (m, HBÀC(4)); 1.13 (2s, 2 MeÀC(8)). 13C-NMR (125 MHz, CDCl3): 172.0 (C(1'));
154.8 (C(2)); 135.1, 129.3, 128.7, 127.3 (Ar); 89.7 (C(3')); 86.3 (C(7a)); 72.7 (C(3a)); 71.5 (C(2')); 48.6 (C(8));
42.3 (C(6)); 35.6 (C(4')); 34.8 (C(7)); 26.0 (C(5)); 25.9 (C(4)); 20.4, 18.7 (2 MeÀC(8)). HR-ESI-MS: 389.1718
‡
([M ‡ H] , C20H25N2O6; calc. 389.1707). Anal. calc. for C20H24N2O6: C 61.88, H 6.23, N 7.22; found C 61.56, H
6.06, N 6.99.
(3aS,6R,7aR)-Tetrahydro-3-[(2S,3S)-2-hydroxy-3-nitro-4-phenylbutanoyl]-8,8-dimethyl-3a,6-methano-1,3-
benzoxazol-2(4H)-one (4f). 1H-NMR (125 MHz, CDCl3; selected signals): 5.36 (dd, J(2',3') ˆ 2.7, J(2',OH) ˆ
7.1, H ÀC(2')); 4.40 (dd, J(7a,7A) ˆ 4.2, J(7a,7B) ˆ 8.2, HÀC(7a)); 3.86 (d, J(2',OH) ˆ 7.1, OH); 3.56 (dd, J ˆ
14.4, J(3',4'A) ˆ 8.7, HAÀC(4')); 3.32 (dd, J ˆ 14.4, J(3',4'B) ˆ 5.8, HBÀC(4')); 1.15, 1.02 (2s, 2 MeÀC(8)).
13C-NMR (125 MHz, CDCl3; selected signals): 171.8 (C(1')); 154.9 (C(2)); 135.0, 129.3, 128.7, 127.4 (Ar); 89.7
(C(3')); 86.2 (C(7a)); 72.8 (C(3a)); 71.5 (C(2')); 48.2 (C(8)); 42.5 (C(6)); 35.5 (C(4')); 34.5 (C(7)); 25.8 (C(5));
24.7 (C(4)); 21.4, 19.1 (2 MeÀC(8)).
(3aS,6R,7aR)-Tetrahydro-3-[(2R,3S)-2-hydroxy-3-nitro-4-phenylbutanoyl]-8,8-dimethyl-3a,6-methano-
1,3-benzoxazol-2(4H)-one (5f). 1H-NMR (500 MHz, CDCl3 ; selected signals): 4.29 (dd, J(7,7A) ˆ 4.1,
J(7,7B) ˆ 8.2, HÀC(7a)); 4.46 (dd, J ˆ 14.6, J(3',4'A) ˆ 6.2, HAÀC(4')); 1.11, 1.03 (2s, 2 MeÀC(8)). 13C-NMR
(125 MHz, CDCl3; selected signals): 172.3 (C(1')); 155.5 (C(2)); 134.6, 129.1, 128.8, 127.6 (Ar); 86.4 (C(3')); 86.3
(C(7a)); 72.7 (C(3a)); 69.5 (C(2')); 48.4 (C(8)); 42.3 (C(6)); 35.2 (C(4')); 34.6 (C(7)); 25.7 (C(5)); 25.0 (C(4));
21.2, 18.9 (2 MeÀC(8)).
(3aS,6R,7aR)-Tetrahydro-3-[(2R,3R)-2-hydroxy-3-nitro-4-phenylbutanoyl]-8,8-dimethyl-3a,6-methano-
1,3-benzoxazol-2(4H)-one (6f). 1H-NMR (500 MHz, CDCl3 ; selected signals): 5.38 (dd, J(2',3') ˆ 6.9,
J(2',OH) ˆ 6.4, HÀC(2')); 5.45 (ddd, J(2',3') ˆ 6.9, J(3',4'B) ˆ 8.1, J(3',4'A) ˆ 8.9, HÀC(3')); 4.38
(dd, J(7a,7A) ˆ 4.2, J(7a,7B) ˆ 8.2, HÀC(7a)); 3.43 (dd, J ˆ 14.8, J(3',4'A) ˆ 8.1, HAÀC(4')); 3.36 (dd, J ˆ
14.8, J(3',4'B) ˆ 3.0, HBÀC(4')); 1.04, 1.01 (2s, 2 MeÀC(8)). 13C-NMR (125 MHz, CDCl3; selected signals):
171.0 (C(1')); 155.8 (C(2)); 138.4 (Ar); 72.6 (C(3a)); 70.7 (C(2')); 48.3 (C(8)); 42.2 (C(6)); 21.2, 18.9
(2 MeÀC(8)).
General Procedure for the Synthesis of Nitro Diols from Compounds 3 6. To an ice-cold soln. of the nitro
alcohol (1.0 mmol) in THF (1 ml), NaBH4 (1.1 mmol) was added portionwise, and the reaction was monitored
by TLC until complete. The mixture was quenched by addition of sat. aq. NaCl soln. and extracted with AcOEt.
The combined org. extracts were dried (MgSO4) and evaporated. All products were purified by CC (hexane/
AcOEt 8 :2 to 4 :6).

Helvetica Chimica Acta Vol. 87 (2004)
1733
(2S,3R)-3-Nitrooctane-1,2-diol ((2S,3R)-7). Yield: 88%. Rf (hexane/AcOEt 1 :1) 0.2. [a]2D0 ˆ 10.5 (c ˆ 1.74,
MeOH). IR (film): 3371, 2958, 2931, 2863, 1554, 1464, 1377, 1099, 1039, 833. 1H-NMR (200 MHz, CDCl3): 4.64
(ddd, J(2,3) ˆ 8.3, J(3,4A) ˆ 3.9, J(3,4B) ˆ 10.4, HÀC(3)); 4.15 (ddd, J(2,3) ˆ 8.3, J(2,1A) ˆ 3.0, J(2,1B) ˆ 5.5,
HÀC(2)); 3.79 (dd, J ˆ 11.9, J(2,1A) ˆ 3.0, HAÀC(1)); 3.61 (dd, J ˆ 11.9, J(2,1B) ˆ 5.5, HBÀC(1)); 2.10 1.87
(m, HAÀC(4)); 1.83 1.63 (m, HBÀC(4)); 1.50 1.10 (m, CH2(5), CH2(6), CH2(7)); 0.88 0.82 (m, Me(8)).
13C-NMR (50 MHz, CDCl3): 90.3 (C(3)); 72.5 (C(2)); 62.9 (C(1)); 30.9 (C(4)); 29.9 (C(5)); 25.2 (C(6)); 22.2
‡
‡
(C(7)); 13.8 (Me(8)). HR-ESI-MS: 214.1054 ([M ‡ Na] , C8H17NNaO4 ; calc. 214.1050). Anal. calc. for
C8H17NO4: C 50.25, H 8.96, N 7.32; found: C 50.03, H 8.83, N 7.20.
(2S,3S)-3-Nitrooctane-1,2-diol ((2S,3S)-7). Yield: 85%. Rf (hexane/AcOEt 1:1) 0.2. [a]2D0 ˆ À21.0 (c ˆ 1.70,
MeOH). 1H-NMR (200 MHz, CDCl3): 4.63 (ddd, J(2,3) ˆ 5.8, J(3,4A) ˆ 3.5, J(3,4B) ˆ 10.3, HÀC(3)); 4.09
(dd, J(2,3) ˆ J(2,1A) ˆ 5.8, J(2,1B) ˆ 3.8, HÀC(2)); 3.76 (dd, J ˆ 11.7, J(2,1B) ˆ 3.8, HBÀC(1)); 3.66 (dd, J ˆ
11.7, J(2,1A) ˆ 5.8, HAÀC(1)); 2.30 1.80 (m, CH2(4)); 1.60 1.30 (m, CH2(5), CH2(6), CH2(7)); 0.99 082
(m, Me(8)). 13C-NMR (50 MHz, CDCl3): 89.4 (C(3)); 72.2 (C(2)); 62.7 (C(1)); 31.0 (C(4)); 29.0 (C(5)); 25.4
(C(6)); 22.2 (C(7)); 13.8 (Me(8)).
(4R,5S)-4-Benzyl-3-[(tert-butoxy)carbonyl]-2,2-dimethyl-1,3-oxazolidine-5-carboxylic acid (9). H2 was
bubbled through a soln. of 3f (0.39 mmol) in MeOH (5 ml) in the presence of a cat. amount of Raney-Ni.
When the reaction was finished (TLC), the catalyst was filtered off and the solvent was evaporated. The residue
was dissolved in AcOEt/sat. NaHCO3 soln. 1:1 (10 ml), and (Boc)2O (0.43 mmol) was added. After 2 h of
stirring, the layers were separated, and the aq. phase was extracted with CH2Cl2. The org. phase was dried
(MgSO4), and the solvents were removed under reduced pressure. The residue was dissolved in toluene (2 ml).
Then, dimethoxypropane (0.21 mmol) and a cat. amount of 4-methylbenzenesulfonic acid (TsOH) were added.
The mixture was heated at 508 (TLC control). After 5 h, the mixture was cooled, the solvents were evaporated,
and the residue was dissolved in THF/H2O 3 :1 (4 ml). This mixture was cooled to 08, and LiOH (3 equiv.) in aq.
28% H2O2 (6 equiv.) was added. After 2 h at r.t., peroxides were decomposed by addition of an excess of aq.
Na2SO3 soln. The mixture was extracted with CH2Cl2 (3Â), the combined extracts were dried (MgSO4),
evaporated in vacuo, and purified by CC (SiO2; hexane/AcOEt 8 :2 ! 6 :4) to give the recovered prosthetic
group in 50% overall yield. The aq. phase was acidified with 3n aq. HCl and extracted with CH2Cl2 (3Â). The
combined org. layers were dried (MgSO4), evaporated, and the residue was subjected to CC (SiO2; CH2Cl2/
MeOH 95 :5 ! 9 :1) to afford 9 in 60% overall yield. [a]2D0 ˆ 17.5 (c ˆ 1.56, CHCl3); lit. [a]D20 ˆ 16.6 (c ˆ 0.81,
CHCl3) [4b].
(4R,5S)-4-Methyl-2-oxo-5-phenyl-1,3-oxazolidin-3-yl](oxo)acetaldehyde (12). Method 1. To a soln. of
(4R,5S)-N-crotonoyl-4-methyl-5-phenyloxazolidinone [10] (4.66 g, 19 mmol) in dioxane/H2O 3 :1 (80 ml),
OsO4 (5.7 ml of a 0.05m soln. in t-BuOH; 0.285 mmol) was added. After 15 min, NaIO4 (10.16 g, 47 mmol) was
added. The reaction was monitored by TLC. After 12 h, the two phases were separated, and the aq. layer was
extracted with AcOEt (3Â). The combined extracts were dried (MgSO4), evaporated, and the residue was
purified by CC (hexane/AcOEt 8 :2 ! 1:1) to give a mixture of the corresponding glyoximide and its hydrate.
This mixture was heated at 808 under reduced pressure (0.2 mm Hg) for 2 h to give 12 in 88% yield. For
characterization, see below.
Method 2. A soln. of (4R,5S)-N-crotonoyl-4-methyl-5-phenyloxazolidinone (4.19 g, 17.1 mmol) [10] in
MeOH/CH2Cl2 2 :5 (280 ml) was cooled to À 788. O3 was bubbled through this mixture until the blue color
persisted. The excess of O3 was purged with O2, followed by addition of Me2S. After stirring for 16 h, the solvents
were evaporated and the residue was purified by CC (hexane/AcOEt 8 :2 ! 1:1) to give a mixture of the
glyoximide and its hydrate. This mixture was heated at 808 under reduced pressure (0.2 mm Hg) for 2 h to give
compound 12 in 80% yield. Rf (hexane/AcOEt 1:1) 0.2. [a]2D0 ˆ 73.5 (c ˆ 0.67; CHCl3). IR (film): 3455, 2983,
1
1787, 1711, 1354, 1200, 1149, 1122, 1032, 957, 765, 701. H-NMR (200 MHz, CDCl3 ): 9.91 (s, CHO); 7.51 7.25
(m, Ph); 5.91 (d, J(4,5) ˆ 7.5, HÀC(5)); 4.78 (dq, J(4,5) ˆ 7.5, J(Me,4) ˆ 6.7, HÀC(4)); 1.00 (d, J ˆ 6.7, Me).
13C-NMR (50 MHz, CDCl3 ): 184.8 (CHO); 162.8 (NÀCˆO); 153.5 (C(2) ˆ O); 132.3, 129.1, 128.8, 125.6 (Ph);
‡
‡
81.5 (C(5)); 54.0 (C(4)); 14.3 (Me). HR-ESI-MS5): 302.0991 ([M ‡ H] , C14H17NO5 ; calc. 302.0999). Anal.
calc. for C12H11NO4: C 61.80, H 4.75, N 6.00; found C 61.77, H 4.99, N 5.81.
(4R,5S)-3-[(2R)-2-Hydroxy-3-nitropropanoyl]-4-methyl-5-phenyl-1,3-oxazolidin-2-one ((2'R)-13a). Rf
(hexane/AcOEt 6 :4) 0.5. IR (film): 3416, 2981, 1784, 1750, 1713, 1557, 1455, 1353, 1201, 1150, 1122, 1067, 957,
766, 701. 1H-NMR (500 MHz, CDCl3): 7.46 7.37 (m, 4 arom. H); 7.33 7.28 (m, 1 arom. H); 5.84 (d, J(4,5) ˆ 7.2,
HÀC(5)); 5.52 5.47 (m, HÀC(2')); 4.91 (dd, J ˆ 13.9, J(2',3'A) ˆ 4.7, HAÀC(3')); 4.84 (dd, J ˆ 13.9, J(2',3'B) ˆ
5
)
Data refer to the corresponding methyl acetal.

1734
Helvetica Chimica Acta Vol. 87 (2004)
5.5, HBÀC(3')); 4.89 4.78 (m, HÀC(4)); 0.97 (d, J ˆ 6.6, Me). 13C-NMR (125 MHz, CDCl3): 169.6 (C(1'));
153.4 (C(2)); 132.2, 128.7, 125.6 (Ph); 80.5 (C(3')); 76.2 (C(5)); 68.1 (C(2')); 55.6 (C(4)); 14.2 (Me). HR-ESI-
‡
‡
MS: 317.0758 ([M ‡ Na] , C13H14N2NaO6 ; calc. 317.0744). Anal. calc. for C13H14N2O6: C 53.06, H 4.80, N 9.52;
found: C 52.84, H 5.17, N 8.98.
(4R,5S)-3-[(2S)-2-Hydroxy-3-nitropropanoyl]-4-methyl-5-phenyl-1,3-oxazolidin-2-one
((2'S)-13a).
1H-NMR (500 MHz, CDCl3 ; selected signals): 4.97 (dd, J ˆ 13.6, J(2',3'A) ˆ 5.0, HAÀC(3')); 4.91 (dd, J ˆ
13.6, J(2',3'B) ˆ 4.2, HBÀC(3')); 0.97 (d, J ˆ 6.7, MeÀC(4)). 13C-NMR (125 MHz, CDCl3; selected signals):
170.0 (C(1')); 153.0 (C(2)); 132.5, 129.1, 125.6 (Ph); 80.4 (C(3')); 77.2 (C(5)); 68.4 (C(2')); 55.1 (C(4)); 14.3
(MeÀC(4)).
(4R,5S)-3-(2-Hydroxy-3-nitrooctanoyl)-4-methyl-5-phenyl-1,3-oxazolidin-2-one (13b). Four diastereoiso-
mers; configurations not determined. Rf (hexane/AcOEt 6 :4) 0.6. IR (film): 3382, 2958, 2932, 2872, 1784, 1738,
1699, 1557, 1537, 1455, 1372, 1353, 1201, 1151, 1124, 766, 702. 1H- and 13C-NMR: see below. HR-ESI-MS:
‡
‡
387.1564 ([M ‡ Na] , C18H24N2NaO6 ; calc. 387.1527). Anal. calc. for C18H24N2O6: C 59.33, H 6.64, N 7.69; found
C 60.00, H 7.00, N 7.39.
Selected NMR Data for Diastereoisomer 1 of 13b. 1H-NMR (200 MHz, CDCl3): 7.50 7.20 (m, 5 arom. H);
5.84 (d, J(4,5) ˆ 7.2, HÀC(5)); 5.34 (dd, J(2',3') ˆ 3.5, J(2',OH) ˆ 7.8, HÀC(2')); 4.97 (ddd, J(2',3') ˆ 5.3,
J(3',4'B) ˆ 13.9, J(3',4'A) ˆ 8.8, HÀC(3')); 4.98 4.65 (m, HÀC(4)); 3.79 (d, J(2,OH) ˆ 7.8, OH); 4.36 2.15
(m, HAÀC(4')); 2.14 1.89 (m, HBÀC(4')); 1.58 1.10 (m, CH2(5'), CH2(6'), CH2(7')); 0.94 0.84 (m, Me(8')).
13C-NMR (50 MHz, CDCl3): 170.5 (C(1')); 153.0 (C(2)); 132.2, 129.1, 128.9, 125.5 (Ph); 88.7 (C(3')); 80.5
(C(5)); 71.2 (C(2')); 55.9 (C(4)); 31.1 (C(4')); 29.4 (C(5')); 25.2 (C(6')); 22.2 (C(7'));14.2 (Me(4)); 13.8
(Me(7')).
Selected NMR Data for Diastereoisomer 2of 13b. 1H-NMR (200 MHz, CDCl3): 5.81 (d, J(4,5) ˆ 7.8,
HÀC(5)); 5.32 (dd, J(2',3') ˆ 2.7, J(2',OH) ˆ 8.5, HÀC(2')); 5.11 (ddd, J(2',3') ˆ 2.7, J(3',4'B) ˆ 5.5, J(3',4'A) ˆ
8.8, HÀC(3')); 3.64 (d, J(2',OH) ˆ 8.5, OH); 0.97 (d, J ˆ 6.7, MeÀC(4)). 13C-NMR (50 MHz, CDCl3): 170.7
(C(1')); 152.8 (C(2)); 132.5, 128.8, 125.7 (Ph); 88.8 (C(3')); 80.3 (C(5)); 71.2 (C(2')); 55.0 (C(4)); 31.1 (C(4'));
29.3 (C(5')); 25.2 (C(6')); 22.2 (C(7')); 14.3 (MeÀC(4)); 13.8 (Me(8')).
Selected NMR Data for Diastereoisomer 3 of 13b. 1H-NMR (200 MHz, CDCl3): 5.80 (d, J(4,5) ˆ 7.2,
HÀC(5)); 5.47 (dd, J(2',3') ˆ 7.2, J(2',OH) ˆ 7.3, HÀC(2')); 4.93 (ddd, J(2',3') ˆ 7.2, J(3',4'B) ˆ 2.2, J(3',4'A) ˆ
4.1, HÀC(3')); 4.04 (d, J(2',OH) ˆ 7.3, OH); 0.91 (d, J ˆ 6.6, MeÀC(4)). 13C-NMR (50 MHz, CDCl3): 169.8
(C(1')); 153.4 (C(2)); 132.5, 129.1, 125.6 (Ph); 86.2 (C(3')); 80.3 (C(5)); 70.7 (C(2')); 55.0 (C(4)); 31.1 (CH2(4'));
28.9 (CH2(5')); 24.9 (CH2(6')); 22.2 (CH2(7')); 14.3 (MeÀC(4)); 13.8 (Me(8')).
Selected NMR Data for Diastereoisomer 4 of 13b. 1H-NMR (200 MHz, CDCl3): 5.79 (d, J(4,5) ˆ 7.3,
HÀC(5)); 5.23 (dd, J(2',3') ˆ 6.3, J(2',OH) ˆ 8.5, HÀC(2')). 13C-NMR (50 MHz, CDCl3): 169.1 (C(1')); 154.0
(C(2)); 140.4, 129.8, 125.9 (Ar); 85.6 (C(3')); 80.6 (C(5)); 69.9 (C(2')); 55.4 (C(4)); 31.0 (CH2(4')); 29.8
(CH2(5')); 24.7 (CH2(6')); 22.2 (CH2(7')); 14.1 (MeÀC(4)); 12.6 (Me(8')).
(4R,5S)-3-(2-Hydroxy-3-nitro-3-phenylpropanoyl)-4-methyl-5-phenyl-1,3-oxazolidin-2-one (13c). Yield af-
ter repeated CC: 12%. Four diastereoisomers; configurations not determined.
Data for Diastereoisomer 1 of 13c. Rf (hexane/AcOEt 6 :4) 0.5. [a]2D0 ˆ 10.6 (c ˆ 0.98; CHCl3). IR (film):
3419, 2984, 1782, 1706, 1557, 1456, 1455, 1353, 1200, 1150, 1123, 1067, 765, 700. 1H-NMR (200 MHz, CDCl3):
7.67 7.59 ( m, 2 arom. H); 7.48 7.36 (m, 6 arom. H); 7.29 7.21 (m, 2 arom. H); 6.03 (d, J(2',3') ˆ 5.8,
HÀC(3')); 5.91 (dd, J(2',3') ˆ 5.8, J(2',OH) ˆ 7.8, HÀC(2')); 5.76 (d, J(4,5) ˆ 7.7, H ÀC(5)); 4.81 (dq, J(4,5) ˆ
7.7, J(4,Me) ˆ 6.6, HÀC(4)); 4.06 (d, J(2',OH) ˆ 7.8, OH); 0.74 (d, J ˆ 6.6, MeÀC(4)). 13C-NMR (50 MHz,
CDCl3): 169.5 (C(1')); 152.9 (C(2)); 132.5, 130.7, 129.2, 129.1, 128.8, 125.6 (Ph); 91.5 (C(3')); 80.0 (C(5)); 71.7
‡
‡
(C(2')); 54.7 (C(4)); 14.2 (MeÀC(4)). HR-LSI-MS: 371.12121 ([M ‡ H] , C19H19N2O6 ; calc. 371.12431). Anal.
calc. for C19H18N2O6: C 61.62, H 4.90, N 7.56; found: C 62.03, H 5.26, N 7.62.
Selected NMR Data for Diastereoisomer 2of 13c. 1H-NMR (200 MHz, CDCl3): 5.84 (d, J(2',3') ˆ 7.3,
HÀC(3')); 5.44 (d, J(4,5) ˆ 7.1, H ÀC(5)); 4.56 (dq, J(4,5) ˆ 7.1, J(4,Me) ˆ 6.6, HÀC(4)); 0.88 (d, J ˆ 6.6,
MeÀC(4)). 13C-NMR (50 MHz, CDCl3): 168.6 (C(1')); 153.0 (C(2)); 132.1, 130.7, 130.2, 128.9, 128.7, 125.4 (Ph);
91.6 (C(3')); 80.0 (C(5)); 71.4 (C(2')); 55.4 (C(4)); 14.0 (Me(4)).
Selected NMR Data for Diastereoisomer 3 of 13c. 1H-NMR (200 MHz, CDCl3): 5.81 (d, J(2',3') ˆ 7.6,
HÀC(3')); 0.80 (d, J ˆ 6.5, MeÀC(4)). 13C-NMR (50 MHz, CDCl3): 169.5 (C(1')); 153.2 (C(2)); 132.5, 130.9,
130.2, 129.1, 128.9, 128.7 (Ph); 88.3 (C(3')); 80.2 (C(5)); 70.9 (C(2')); 54.9 (C(4)); 14.3 (MeÀC(4)).
Selected NMR Data for Diastereoisomer 4 of 13c. 1H-NMR (200 MHz, CDCl3): 4.79 (dq, J(4,5) ˆ 6,7,
J(4,Me) ˆ 6.6, HÀC(4)); 0.95 (d, J ˆ 6.6, MeÀC(4)). 13C-NMR (50 MHz, CDCl3): 169.1 (C(1')); 153.7 (C(2));
132.3, 131.5, 130.0, 129.9, 128.3, 125.5 (Ph); 88.1 (C(3')); 80.4 (C(5)); 70.2 (C(2')); 55.2 (C(4)); 13.8 (MeÀC(4)).

Helvetica Chimica Acta Vol. 87 (2004)
1735
(4R,5S)-3-(4,4-Diethoxy-2-hydroxy-3-nitrobutanoyl)-4-methyl-5-phenyl-1,3-oxazolidin-2-one (13d). Four
diastereoisomers; configurations not determined. Rf (hexane/AcOEt 6 :4) 0.5. IR (film): 3464, 2981, 2935,
1786, 1738, 1708, 1555, 1353, 1221, 1200, 1149, 1121, 1067, 1033, 979, 765, 701. 1H- and 13C-NMR: see below. HR-
‡
‡
ESI-MS: 419.1427 ([M ‡ Na] , C18H24N2NaO8 ; calc. 419.1425). Anal. calc. for C18H24N2O8: C 54.54, H 6.10, N
7.07; found: C 54.41, H 6.30, N 6.78.
NMR Data for Diastereoisomer 1 of 13d. 1H-NMR (200 MHz, CDCl3): 7.46 7.38 (m, 4 arom. H); 7.33 7.28
(m, 1 arom. H); 5.82 (d, J(4,5) ˆ 7.0, H ÀC(5)); 5.72 (dd, J(2',3') ˆ 3.4, J(2',OH) ˆ 8.8, HÀC(2')); 5.27
(d, J(3',4') ˆ 7.9, HÀC(4')); 5.09 (dd, J(2',3') ˆ 3.4, J(3',4') ˆ 7.9, HÀC(3')); 4.74 (dq, J(4,5) ˆ 7.0, J(4,Me) ˆ
6.6, HÀC(4)); 3.86 3.71 (m, 2 MeCH2O); 1.28 (t, J ˆ 7.0, MeCH2O); 1.18 (t, J ˆ 7.0, MeCH2O); 0.96 (d, J ˆ
6.6, MeÀC(4)). 13C-NMR (50 MHz, CDCl3): 170.4 (C(1')); 152.6 (C(2)); 132.3, 129.1, 128.8, 125.6 (Ph); 99.2
(C(4')); 88.6 (C(3')); 80.3 (C(5)); 69.8 (C(2')); 64.6 (MeCH2O)); 63.2 (MeCH2O); 55.8 (C(4)); 15.2
(MeÀC(4)); 14.9 (MeCH2O); 14.2 (MeCH2O).
Selected NMR Data for Diastereoisomer 2of 13d. 1H-NMR (200 MHz, CDCl3): 5.63 (d, J(3',4') ˆ 3.0,
HÀC(4')); 5.29 (dd, J(2',3') ˆ 8.0, HÀC(2')); 5.25 (dd, J(2',3') ˆ 8.0, J(3',4') ˆ 3.0, HÀC(3')); 4.82 (dq, J(4,5) ˆ
6.8, J(4,Me) ˆ 6.7, HÀC(4)); 0.95 (d, J ˆ 6.6, MeÀC(4)). 13C-NMR (50 MHz, CDCl3): 169.3 (C(1')); 152.5
(C(2)); 132.6, 128.8, 125.6 (Ph); 99.8 (C(4')); 88.5 (C(3')); 80.3 (C(5)); 70.0 (C(2')); 65.9 (MeCH2O); 65.1
(MeCH2O); 55.0 (C(4)); 15.1 (MeÀC(4)); 14.1 (MeCH2O); 14.0 (MeCH2O).
Selected NMR Data for Diastereoisomer 3 of 13d. 1H-NMR (200 MHz, CDCl3): 5.66 (d, J(4,5) ˆ 7.8,
HÀC(5)); 5.16 (d, J(3',4') ˆ 6.0, HÀC(4')); 5.10 (dd, J(2',3') ˆ 4.6, J(3',4') ˆ 6.0, HÀC(3')); 4.46 (dq, J(4,5) ˆ
7.8, J(4,Me) ˆ 6.6, HÀC(4)); 0.96 (d, J ˆ 6.6, MeÀC(4)). 13C-NMR (50 MHz, CDCl3): 168.0 (C(1')); 152.6
(C(2)); 132.3, 129.1, 128.8 (Ph); 80.3 (C(5)); 55.9 (C(4)).
Selected NMR Data for Diastereoisomer 4 of 13d. 1H-NMR (200 MHz, CDCl3): 4.68 (dq, J(4,5) ˆ 6.8,
J(4,Me) ˆ 6.7, HÀC(4)); 0.93 (d, J ˆ 6.7, MeÀC(4)). 13C-NMR (50 MHz, CDCl3): 169.3 (C(1')); 152.7 (C(2));
132.1, 129.0 (Ph); 80.3 (C(5)), 53.3 (C(4)).
(4R,5S)-3-(4-Ethoxy-2-hydroxy-3-nitro-4-oxobutanoyl)-4-methyl-5-phenyl-1,3-oxazolidin-2-one4) (13e). Rf
(hexane/AcOEt 6 :4) 0.5. IR (film): 3475, 2987, 2935, 1780, 1706, 1568, 1372, 1202, 1153, 1124, 1031, 767, 701. 1H-
‡
‡
and 13C-NMR: see below. HR-LSI-MS: 367.11317 ([M ‡ H] , C16H19N2O8 ; calc. 367.11414). Anal. calc. for
C16H18N2O8: C 52.46, H 4.95, N 7.65; found: C 52.56, H 5.04, N 7.55.
NMR Data for Diastereoisomer 1 of 13e. 1H-NMR (500 MHz, C6D6): 7.05 6.96 (m, 5 arom. H); 6.20
(d, J(2',3') ˆ 7.2, H ÀC(3')); 5.99 (d, J(2',3') ˆ 7.2, H ÀC(2')); 4.70 (d, J(4,5) ˆ 7.6, H ÀC(5)); 4.23 4.01
(m, HÀC(4)); 4.01 3.77 (m, MeCH2O); 0.80 (t, J ˆ 7.1, MeCH2O); 0.62 (d, J ˆ 6.6, MeÀC(4)). 13C-NMR
(125 MHz, C6D6): 169.0 (C(1')); 162.3 (C(4')); 153.1 (C(2)); 133.1, 128.8, 128.1, 125.8 (Ph); 89.2 (C(3')); 79.8
(C(5)); 70.0 (C(2')); 63.3 (MeCH2O); 54.8 (C(4)); 13.7 (MeÀC(4)); 13.6 (MeCH2O).
Selected NMR Data for Diastereoisomer 2of 13e. 1H-NMR (500 MHz, C6D6): 6.13 (d, J(2',3') ˆ 5.6,
HÀC(3')); 5.88 (d, J(2',3') ˆ 5.6, HÀC(2')); 4.62 (d, J(4,5) ˆ 7.4, HÀC(5)); 0.82 (t, J ˆ 7.1, MeCH2O); 0.56
(d, J ˆ 6.6, MeÀC(4)). 13C-NMR (125 MHz, C6D6): 168.6 (C(1')); 162.7 (C(4')); 153.5 (C(2)); 132.9, 128.8, 128.0,
125.7 (Ph); 87.4 (C(3')); 79.9 (C(5)); 69.9 (C(2')); 63.3 (MeCH2O); 55.1 (C(4)); 13.7 (MeÀC(4)); 13.6
(MeCH2O).
Selected NMR Data for Diastereoisomer 3 of 13e. 1H-NMR (500 MHz, C6D6): 6.10 (d, J(2',3' ˆ 8.7,
HÀC(3')); 5.97 (d, J(2',3') ˆ 8.7, HÀC(2')); 4.72 (d, J(4,5) ˆ 7.7, H ÀC(5)); 0.86 (t, J(5,6) ˆ 7.1, MeCH2O); 0.51
(d, J ˆ 6.6, MeÀC(4)). 13C-NMR (125 MHz, C6D6): 169.0 (C(1')); 162.9 (C(4')); 153.2 (C(2)); 133.1, 128.9, 128.2,
125.8 (Ph); 88.8 (C(3')); 79.9 (C(5)); 70.0 (C(2')); 63.2 (MeCH2O); 54.8 (C(4)); 13.8 (MeÀC(4)); 13.4
(MeCH2O).
Selected NMR Data for Diastereoisomer 4 of 13e. 1H-NMR (500 MHz, C6D6): 6.04 (d, J(2',3') ˆ 7.8,
HÀC(3')); 5.94 (d, J(2',3') ˆ 7.8, HÀC(2')); 4.63 (d, J(4,5) ˆ 7.3, HÀC(5)); 0.89 (t, J(5,6) ˆ 6.7, MeCH2O); 0.52
(d, J ˆ 6.6, MeÀC(4)). 13C-NMR (125 MHz, C6D6): 168.6 (C(1')); 162.7 (C(4')); 153.8 (C(2)); 132.9, 128.8, 128.1,
125.7 (Ph); 86.8 (C(3')); 79.0 (C(5)); 69.6 (C(2')); 64.1 (MeCH2O); 55.2 (C(4)); 13.9 (MeÀC(4)); 13.4
(MeCH2O).
X-Ray Crystal-Structure Analyses. Measurements were made on a Kuma KM4CCD diffractometer, using
the Express software, and without absorption corrections. The structures were solved by direct methods [8] and
refined with the SHELXL97 program [9]. The known configuration of the asymmetric centers has been
confirmed by Flack-parameter refinement. Crystallographic data (excluding structure factors) for the structures
reported in this paper have been deposited with the Cambridge Crystallographic Data Center as supplementary
publication numbers CCDC-230269 (5a), CCDC-230270 (3c), and CCDC-230271 (5c). Copies of the data can
be obtained, free of charge, on application to CCDC, 12 Union Road, Cambridge, CB2 1EZ, UK (fax: ‡44-
1223-336033, e-mail: deposit@ccdc.cam.ac.uk), or via internet (www.ccdc.cam.ac.uk/retrieving.html).

1736
Helvetica Chimica Acta Vol. 87 (2004)
This work was supported by the State Committee for Scientific Research (Project PBZ 605/T09/1999).
REFERENCES
[1] L. Henry, Compt. Rend. 1895, 120, 1265; G. Rosini, R. Ballini, Synthesis 1988, 833; G. Rosini, in
−Comprehensive Organic Synthesis×, Ed. B. M. Trost, Pergamon Press, Oxford, 1991, p. 321 340; F. A.
Luzzio, Tetrahedron 2001, 57, 915; M. Shibasaki, H. Sasai, T. Arai, Angew. Chem., Int. Ed. 1997, 36, 1237.
¬
[2] I. Kudyba, J. Raczko, J. Jurczak, Tetrahedron Lett. 2003, 44, 8681; I. Kudyba, J. Raczko, Z. Urbanczyk-
Lipkowska, J. Jurczak, Tetrahedron 2004, 60, in press.
¬
¬
[3] A. Solladie-Cavallo, N. Khiar, Tetrahedron Lett. 1988, 29, 2189; A. Solladie-Cavallo, N. Khiar, J. Org.
Chem. 1990, 55, 4750.
[4] a) I. Kudyba, J. Raczko, J. Jurczak, Tetrahedron Lett. 2003, 44, 8685; b) I. Kudyba, J. Raczko, J. Jurczak, J.
Org. Chem. 2004, 69, 2844.
[5] T.-H. Yan, V.-V. Chu, T.-C. Lin, C.-H. Wu, L.-H. Liu, Tetrahedron Lett. 1991, 32, 4959; T.-H. Yan, V.-V. Chu,
T.-C. Lin, W.-H. Tseng, T.-W. Cheng, Tetrahedron Lett. 1991, 32, 5563; T.-H. Yan, C.-W. Tan, H.-C. Lee, H.-
C. Lo, T.-Y. Huang, J. Am. Chem. Soc. 1993, 115, 2613; T.-H. Yan, H.-C. Lee, C.-S. Chang, W.-H. Liu, T.-Y.
Huang, J. Org. Chem. 1995, 60, 3301; T.-H. Yan, Y.-C. Wang, C.-S. Chang, T.-H. Yan, T.-Y. Huang, J. Org.
Chem. 1996, 61, 2038.
[6] D. A. Evans, J. Bartroli, T. L. Shih, J. Am. Chem. Soc. 1981, 103, 2127; D. A. Evans, A. S. Kim, − Handbook
of Reagents for Organic Synthesis. Reagents, Auxiliaries, and Catalysts for CÀC Bond Formation×, Eds.
R. M. Coates, S. E. Denmark, John Wiley & Sons, New York, 1999, p. 91.
[7] Y. Wei, W. Yuan, B. Munoz, C.-H. Wong, J. Z. Haeggstrˆm, A. Wetterholm, B. Samuelsson, J. Med. Chem.
1993, 36, 211.
[8] G. M. Sheldrick, Acta Crystallogr., Sect. A 1990, 46, 467.
[9] G. M. Sheldrick, SHELXL97, Program for the Refinement of Crystal Structures, University of Gˆttingen,
Germany, 1997.
[10] D. A. Evans, K. T. Chapman, J. Bisaha, J. Am. Chem. Soc. 1984, 106, 4261.
Received March 2, 2004