PAPER
Chiral Benzylsulfanyloxazolines in Pd-Catalyzed Cross-Coupling
861
13C NMR (CDCl3): d = 166.1, 162.9, 130.9 (2 × C), 119.5, 113.9
(2 × C), 101.4, 89.2, 86.1, 62.5, 55.5, 26.0, 25.9, 18.4, 18.2, –4.6
(2 × C), –5.3, –5.4; C3¢ under CDCl3 triplet.
MS (IS): m/z = 495 [M + H]+.
HRMS-ESI: m/z [M + H]+ calcd for C25H44NO5Si2: 494.2758;
found: 494.2740.
HRMS-ESI: m/z [M + Na]+ calcd for C25H43O5NNaSi2: 516.2578;
found: 516.2582.
IR (KBr): 1636, 1431, 1114, 1068, 1037, 837, 784 cm–1.
1H NMR (CDCl3): d = 7.69 (dd, 3J = 1.0 Hz, 3J = 3.5 Hz, 1 H, H-5
thienyl), 7.52 (dd, 3J = 1.0 Hz, 3J = 5.0 Hz, 1 H, H-3 thienyl), 7.10
(dd, 3J = 3.8 Hz, 3J = 4.7 Hz, 1 H, H-4 thienyl), 6.19 (d, 3J = 6.0 Hz,
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1 H, H-1¢), 4.84 (dd, J = 1.3 Hz, J = 6.0 Hz, 1 H, H-2¢), 4.48 (d,
3J = 1.6 Hz, 1 H, H-3¢), 3.98 (ddd, 3J = 2.8 Hz, 3J = 4.7 Hz, 3J = 8.0
Hz, 1 H, H-4¢), 3.63 (dd, 3J = 4.7 Hz, 2J = 10.7 Hz, 1 H, H-5¢a), 3.37
(dd, 3J = 8.0 Hz, 2J = 10.7 Hz, 1 H, H-5¢b), 0.93 [s, 9 H, (CH3)3C],
0.80 [s, 9 H, (CH3)3C], 0.18 (s, 3 H, CH3Si), 0.15 (s, 3 H, CH3Si),
–0.03 (s, 3 H, CH3Si), –0.05 (s, 3 H, CH3Si).
2-(2-Furyl)-4,5-dihydro(3¢,5¢-di-O-tert-butyldimethylsilyl-1¢,2¢-
dideoxy-b-D-arabinofuranoso)-[1,2-d]-oxazole (3b)
Prepared from 1b (154 mg, 0.30 mmol) and 2-furylboronic acid (75
mg, 0.67 mmol).
13C NMR (CDCl3): d = 161.9, 131.9, 131.4, 129.5, 127.9, 101.4,
89.7, 86.2, 77.4, 62.4, 25.9 (2 × C), 18.4, 18.2, –4.7 (2 × C), –5.3,
–5.4.
MS (IS): m/z = 471 [M + H]+.
HRMS (EI): m/z [M – t-Bu]+ calcd for C18H30NO4SSi2: 412.1434;
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Yield: 75 mg (55%); yellow oil; [a]D –21 (c 1.0, CH2Cl2);
Rf = 0.13 (PE–EtOAc, 9:1).
found: 412.1421.
IR (KBr): 2928, 1665, 1254, 1106, 836, 778 cm–1.
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1H NMR (CDCl3): d = 7.58 (d, J = 1.0 Hz, 1 H, H-5 furyl), 7.08
2-[(E)-2-Phenylethenyl]-4,5-dihydro(3¢,5¢-di-O-tert-butyldi-
methylsilyl-1¢,2¢-dideoxy-b-D-arabinofuranoso)-[1,2-d]-oxazole
(3e)
Prepared from 1b (160 mg, 0.31 mmol) and 2-(E)-(tributylstan-
nyl)styrene (272 mg, 0.69 mmol).
(dd, 3J = 1.0 Hz, 3J = 3.5 Hz, 1 H, H-3 furyl), 6.52 (dd, 3J = 1.9 Hz,
3J = 3.5 Hz, 1 H, H-4 furyl), 6.21 (d, 3J = 6.0 Hz, 1 H, H-1¢), 4.82
(dd, 3J = 1.3 Hz, 3J = 6.3 Hz, 1 H, H-2¢), 4.48 (d, 3J = 1.3 Hz, 1 H,
H-3¢), 3.98 (ddd, J = 2.9 Hz, J = 4.7 Hz, J = 8.2 Hz, 1 H, H-4¢),
3.62 (dd, 3J = 4.7 Hz, 2J = 10.7 Hz, 1 H, H-5¢a), 3.34 (dd, 3J = 8.2
Hz, 2J = 10.7 Hz, 1 H, H-5¢b), 0.93 [s, 9 H, (CH3)3C], 0.84 [s, 9 H,
(CH3)3C], 0.17 (s, 3 H, CH3Si), 0.14 (s, 3 H, CH3Si), –0.03 (s, 3 H,
CH3Si), –0.05 (s, 3 H, CH3Si).
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Yield: 100 mg (65%); colorless oil; [a]D +3 (c 1.0, CH2Cl2);
Rf = 0.16 (PE–EtOAc, 9:1).
IR (KBr): 1655, 1472, 1351, 1253, 1110, 1062, 1021, 835, 778
cm–1.
13C NMR (CDCl3): d = 158.3, 146.3, 142.4, 116.4, 111.9, 101.3,
89.4, 86.5, 77.3, 62.4, 26.0, 25.9, 18.4, 18.2, –4.7 (2 × C), –5.3,
–5.4.
1H NMR (CDCl3): d = 7.33–7.47 (m, 6 H, HAr and H-1 styryl), 6.57
(d, 3J = 16.3 Hz, 1 H, H-2 styryl), 6.09 (d, 3J = 6.3 Hz, 1 H, H-1¢),
4.72 (dd, 3J = 1.3 Hz, 3J = 6.0 Hz, 1 H, H-2¢), 4.41 (d, 3J = 1.0 Hz,
1 H, H-3¢), 3.93 (ddd, 3J = 2.8 Hz, 3J = 4.7 Hz, 3J = 7.9 Hz, 1 H, H-
4¢), 3.59 (dd, 3J = 4.7 Hz, 2J = 10.7 Hz, 1 H, H-5¢a), 3.32 (dd,
3J = 8.5 Hz, 2J = 10.7 Hz, 1 H, H-5¢b), 0.90 [s, 9 H, (CH3)3C], 0.80
[s, 9 H, (CH3)3C], 0.15 (s, 3 H, CH3Si), 0.11 (s, 3 H, CH3Si), –0.03
(s, 3 H, CH3Si), –0.04 (s, 3 H, CH3Si).
13C NMR (CDCl3): d = 165.8, 142.4, 135.0, 130.1, 129.1 (2 × C),
127.9 (2 × C), 114.7, 101.2, 88.9, 86.3, 77.5, 62.5, 26.0, 25.9, 18.5,
18.2, –4.6 (2 × C), –5.2, –5.3.
MS (IS): m/z = 455 [M + H]+.
HRMS-EI: m/z [M – t-Bu]+ calcd for C18H30NO5Si2: 396.1663;
found: 396.1670.
2-(4-Pyridyl)-4,5-dihydro(3¢,5¢-di-O-tert-butyldimethylsilyl-
1¢,2¢-dideoxy-b-D-arabinofuranoso)-[1,2-d]-oxazole (3c)
Prepared from 1b (151 mg, 0.30 mmol) and 4-(tributylstannyl)pyri-
dine (240 mg, 0.65 mmol).
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Yield: 113 mg (82%); yellow oil; [a]D –7 (c 1.0, CH2Cl2);
MS (IS): m/z = 491 [M + H]+.
Rf = 0.06 (PE–EtOAc, 9:1).
Anal. Calcd for C26H43NO4Si2: C, 63.76; H, 8.85; N, 2.86. Found:
C, 64.11; H, 8.92; N, 2.63.
IR (KBr): 1650, 1472, 1410, 1352, 1254, 1097, 1065, 1004, 835,
778 cm–1.
1H NMR (CDCl3): d = 8.75 (d, 3J = 6.0 Hz, 2 H, H-2 pyridyl), 7.82
(d, 3J = 6.0 Hz, 2 H, H-3 pyridyl), 6.21 (d, 3J = 6.3 Hz, 1 H, H-1¢),
4.89 (dd, 3J = 1.6 Hz, 3J = 6.3 Hz, 1 H, H-2¢), 4.47 (dd, 3J = 1.6 Hz,
3J = 3.4 Hz, 1 H, H-3¢), 3.95 (ddd, 3J = 2.8 Hz, 3J = 4.2 Hz, 3J = 7.0
Hz, 1 H, H-4¢), 3.62 (dd, 3J = 4.2 Hz, 2J = 10.7 Hz, 1 H, H-5¢a), 3.40
(dd, 3J = 7.0 Hz, 2J = 11.0 Hz, 1 H, H-5¢b), 0.94 [s, 9 H, (CH3)3C],
0.77 [s, 9 H, (CH3)3C], 0.19 (s, 3 H, CH3Si), 0.15 (s, 3 H, CH3Si),
–0.04 (s, 3 H, CH3Si), –0.07 (s, 3 H, CH3Si).
2-(2-Furyl)-4,5-dihydro(3¢,5¢-di-O-tert-butyldimethylsilyl-1¢,2¢-
dideoxy-b-L-arabinofuranoso)-[1,2-d]-oxazole (10)
Prepared from 4 (145 mg, 0.28 mmol) (enantiomer of 1b) and 2-fu-
rylboronic acid (70 mg, 0.62 mmol).
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Yield: 72 mg (56%); yellow oil; [a]D +24 (c 1.0, CH2Cl2);
Rf = 0.13 (PE–EtOAc, 9:1).
IR (KBr): 1671, 1652, 1473, 1340, 1254, 1092, 999, 835, 778 cm–1.
13C NMR (CDCl3): d = 164.3, 150.6 (2 × C), 134.5, 122.4 (2 × C),
101.1, 89.9, 85.7, 77.4, 62.1, 25.9 (2 × C), 18.4, 18.2, –4.6, –4.7,
–5.3, –5.4.
1H NMR (CDCl3): d = 7.58 (d, 3J = 1.0 Hz, 1 H, H-5 furyl), 7.08 (d,
3J = 3.5 Hz, 1 H, H-3 furyl), 6.52 (dd, 3J = 1.9 Hz, 3J = 3.5 Hz, 1 H,
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H-4 furyl), 6.21 (d, J = 6.0 Hz, 1 H, H-1¢), 4.82 (dd, J = 1.3 Hz,
3J = 6.0 Hz, 1 H, H-2¢), 4.48 (d, 3J = 1.3 Hz, 1 H, H-3¢), 3.98 (ddd,
3J = 2.8 Hz, 3J = 5.0 Hz, 3J = 8.2 Hz, 1 H, H-4¢), 3.62 (dd, 3J = 5.0
Hz, 2J = 10.7 Hz, 1 H, H-5¢a), 3.34 (dd, 3J = 8.2 Hz, 2J = 10.7 Hz,
1 H, H-5¢b), 0.93 [s, 9 H, (CH3)3C], 0.81 [s, 9 H, (CH3)3C], 0.17 (s,
3 H, CH3Si), 0.14 (s, 3 H, CH3Si), –0.03 (s, 3 H, CH3Si), –0.05 (s,
3 H, CH3Si).
MS (IS): m/z = 466 [M + H]+.
Anal. Calcd for C23H40N2O4Si2: C, 59.44; H, 8.68; N, 6.03. Found:
C, 59.44; H, 8.79; N, 5.74.
2-(2-Thienyl)-4,5-dihydro(3¢,5¢-di-O-tert-butyldimethylsilyl-
1¢,2¢-dideoxy-b-D-arabinofuranoso)-[1,2-d]-oxazole (3d)
Prepared from 1b (129 mg, 0.25 mmol) and 2-(tributylstan-
nyl)thiophene (177 mL, 0.56 mmol).
Yield: 99 mg (83%); colorless crystals; mp 46–48 °C; [a]D20 –30 (c
1.0, CH2Cl2); Rf = 0.23 (PE–EtOAc, 9:1).
13C NMR (CDCl3): d = 158.3, 146.2, 142.4, 116.4, 111.9, 101.3,
89.4, 86.5, 77.3, 62.4, 26.0, 25.9, 18.4, 18.2, –4.7 (2 × C), –5.3,
–5.4.
MS (IS): m/z = 455 [M + H]+.
Synthesis 2007, No. 6, 857–864 © Thieme Stuttgart · New York