3310
A. Breuning et al. / Tetrahedron: Asymmetry 14 (2003) 3301–3312
The b-sulfate was hydrolysed subsequently with 20%
H2SO4 (100 mL) and diethyl ether (100 mL) for 4 h.
The organic layer was dried and evaporated in vacuo.
acetic acid were added. DMF was removed in vacuo
and the crude product purified by column chromatog-
raphy on silica gel with diethyl ether:petrol ether 40–60
(1:3).
4.11.1. (2S,3R)-Dibenzyl-3-azido-2-hydroxy succinate
(2S,3R)-6c. 82% as colourless crystals; mp: 33–34°C;
TLC cyclohexane:ethyl acetate 3:1, Rf=0.45; [h]2D0=
−37.1 (c 1.02, MeOH); IR (film): w˜=3412 (m, br), 3062
(s), 3034 (s), 2105 (s), 1747 (s, br, C=O), 1713 (s), 1498
(m), 1456 (m), 1384 (m), 1294 (m), 1268 (m), 1099 (s),
1019 (m), 969 (m), 870 (m), 743 (m), 694 (s, br) cm−1;
1H NMR (CDCl3, 400.13 MHz): l=3.30 (s, 1H, OH),
4.26 (d, 1H, CH, J=2.8 Hz), 4.57 (d, 1H, CH, J=2.8
Hz), 4.93 (t, 2H, CH2), 4.98 (t, 2H, CH2), 7.25–7.32 (m,
10H, 2 C6H5) ppm; 13C NMR (CDCl3, 100.62 MHz):
l=64.84 (CH), 68.52 (CH2), 68.79 (CH2), 72,58 (CH),
129.06 (C6H5), 134.82 (qC), 134.98 (qC), 167.30 (C=
O), 171.03 (C=O) ppm; C18H17N3O5 (355.34), calcd C,
60.84; H, 4.82; N, 11.83; found: C, 60.96; H, 4.78; N,
11.80%.
4.13.1. (S,S)-Dibenzyl aziridine-2,3-dicarboxylate (S,S)-
7c. 38% as colourless crystals; mp: 59–60°C; TLC cyclo-
hexane:ethyl acetate 3:1, Rf=0.34; [h]2D0=+79.3 (c 1.02
in, MeOH); IR (film): w˜=3159 (m, br), 2946 (s), 2889
(s), 1728 (s, br, C=O), 1496 (s), 1455 (m), 1383 (m),
1340 (m), 1271 (m), 1168 (m), 1004 (s), 958 (m), 910
(m), 865 (m), 831 (m), 744 (s), 698 cm−1; 1H NMR
(CDCl3, 400.13 MHz): l=1.84 (s, 1H, NH), 2.94 (s,
2H, CH), 5.20 (t, 4H, 2 CH2), 7.36 (m, 10H, 2 C6H5)
ppm; 13C NMR (CDCl3, 100.62 MHz): l=35.47 (CH),
36.21 (CH), 67.46 (CH2), 68.02 (CH2), 128.65 (C6H5),
134.85 (2 C), 168.43 (C=O), 169.83 (C=O) ppm;
C18H17O4N (311.33), calcd C, 69.44; H, 5.50; N, 4.5;
found: C, 69.51; H, 5.49; N, 4.39%.
4.13.2.
(R,R)-Dibenzyl
aziridine-2,3-dicarboxylate
4.11.2. (2R,3S)-Diallyl-3-azido-2-hydroxy succinate
(2R,3S)-6d. 60% as a colourless oily liquid; TLC cyclo-
hexane:ethyl acetate 3:1, Rf=0.38; [h]2D0=+30.4 (c
2.005, MeOH); IR (film): w˜=3412 (m, br), 3062 (s),
3034 (s),2105 (s), 1747 (s, br, C=O), 1713 (s), 1498 (m),
1456 (m), 1384 (m), 1294 (m), 1268 (m), 1099 (s), 1019
(R,R)-7c. 35% of colourless crystals with the same mp,
1
IR, H and 13C NMR data as (S,S)-7c; [h]2D0=−79.8 (c
1.04, MeOH); C18H17O4N (311.33), calcd C, 69.44; H,
5.50; N, 4.50; found: C, 69.41; H, 5.56; N, 4.41.
4.13.3. (S,S)-Diallyl aziridine-2,3-dicarboxylate (S,S)-
7d. 42% as a yellowish oily liquid, TLC cyclohex-
ane:ethylacetate 3:1, Rf=0.32; [h]2D0=+131.5 (c 1.16,
MeOH); IR (film): w˜=3159 (m, br), 2946 (s), 2889 (s),
1728 (s, br, C=O), 1496 (s), 1455 (m), 1383 (m), 1340
(m), 1271 (m), 1168 (m), 1004 (s), 958 (m), 910 (m), 865
(m), 831 (m), 744 (s), 698 cm−1; 1H NMR (CDCl3,
400.13 MHz): l=1.85 (s, 1H, NH), 2.92 (s, 2H, CH),
4.66 (dt, 4 H, 2 CH2-CH=), 5.28 (dd, 2H, -CH=CH2,
J=1.01 Hz, Jcis=10.61 Hz), 5.34 (dd, 2H, -CH=CH2,
J=1.27 Hz, Jtrans=17.18 Hz), 5.87–5.99 (m, 2H, CH2=
CH-) ppm; 13C NMR (CDCl3, 100.62 MHz): l=36.16
(2 CH), 66.90 (2 CH2-CH=), 119.73 (2 -CH=CH2),
131.60 (2 -CH=CH2), 169.62 (2 C=O) ppm;
C10H13O4N (211.21), calcd C, 56.86; H, 6.20; N, 6.63;
found: C, 56.97; H, 6.12; N, 6.61%.
1
(m), 969 (m), 870 (m), 743 (m), 694 (s, br) cm−1; H
NMR (CDCl3, 400.13 MHz): l=3.33 (s, 1H, OH), 4.39
(d, 1H, CH, J=2.8 Hz), 4.71 (d, 1H, CH, J=2.8 Hz),
5.32 (dd, 2H, -CH=CH2, J=0.76 Hz, Jcis=10.61 Hz),
5.38 (dd, 2H, -CH=CH2, J=1.27 Hz, Jtrans=17.18 Hz),
5.86–5.99 (m, 2H, 2 CH=CH2) ppm; 13C NMR
(CDCl3, 100.62 MHz): l=64.87 (CH), 67.27 (CH2),
67.61 (CH2), 72,49 (CH), 120.05 (-CH=CH2), 120.15
(-CH=CH2), 131.23 (-CH=CH2), 131.34 (-CH=
CH2), 167.08 (C=O), 170.83 (C=O) ppm; C10H13O5N3
(255.23), calcd C, 47.06; H, 5.13; N, 16.46; found: C,
46.91; H, 5.25; N, 16.58%.
4.11.3. (2S,3R)-Diallyl-3-azido-2-hydroxy succinate
(2S,3R)-6d. 60% as a colourless oily liquid with the
1
same IR, H and 13C NMR data as (2R,3S)-6d); [h]2D0=
−30.7 (c 1.06, MeOH); C10H13O5N3 (255.23), calcd C,
47.06; H, 5.13; N, 16.46; found: C, 47.22; H, 5.01; N,
16.35.
4.13.4. (R,R)-Diallyl aziridine-2,3-dicarboxylate (R,R)-
7d. 43% as a yellowish oily liquid, IR, 1H and 13C
NMR data as (S,S)-7d; [h]2D0=−130.8 (c 1.02 in
MeOH); C10H13O4N (211.21), calcd C, 56.86; H, 6.20;
N, 6.63; found: C, 56.98; H, 6.15; N, 6.57%.
4.12. Aziridines 7, 8
The analytical data of the aziridines (S,S)-7a, (R,R)-7a,
(S,S)-7b, (R,R)-7b corresponds to the reported litera-
ture values.14,29,44
4.13.5. (S,S)-1-tert-Butyl-2,3-diethyl aziridine-1,2,3-tri-
carboxylate (S,S)-8b. Aziridine (1.31 g, 7.0 mmol)
(S,S)-7b was dissolved in CH2Cl2abs. (60 mL) and
cooled at 0°C. Di-tert.-butyl dicarbonate (4.58 g, 21.0
mmol) and DMAP (855 mg, 7.0 mmol) were added and
the solution stirred at 0°C for 2 h and then at rt for 2
days. The solution was concentrated and then washed
with water and saturated NH4Cl solution. The organic
layer was dried with Na2SO4 and the residue remaining
after evaporation of the solvent in vacuo purified by
column chromatography on silica gel with cyclohex-
ane:ethyl acetate 2:1. Yield: 31% as a yellowish viscous
oil; [h]2D0=+14.8 (c 1.37, EtOH); IR (film): w˜=2984,
4.13. General procedure for the synthesis of the aziridi-
nes 7
A solution of 10 mmol of the appropriate azido alcohol
6 in DMF (50 mL) was cooled at 0°C. PPh3 (18 mmol)
was added over a period of 30 min in five portions. The
solution was stirred at rt for 1.5 h and then heated at
80°C for another 4.5 h. In the case of the dibenzyl and
diallyl derivatives, the solution was heated immediately
after the addition of PPh3 and catalytic amounts of
1
1744 (s, C=O), 1395, 1371 cm−1; H NMR (CDCl3,