A. Czapla et al. / Tetrahedron: Asymmetry 10 (1999) 2101–2111
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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.