Synthesis of Nucleoside Analogues
517
ꢀ1H, dd, J 10.8 and 6.5 Hz), 3.52 ꢀ1H, dd, J 10.8 Hz and 5.2 Hz), 3.87 ꢀ1H, dd, J 8.5 and
7.1 Hz), 4.09 ꢀ1H, dd, J 8.5 and 7.5 Hz), 5.72 ꢀ1H, d, J 7.5 Hz), 5.88 ꢀ1H, dd, J 6.3 and 5.8 Hz),
13
7.52 ꢀ1H, d, J 7.5 Hz) ppm; C NMR ꢀ100 MHz, CDCl3:CD3OD 10:1): ꢄ 35.82 ꢀC30), 40.84
ꢀC20), 62.62 ꢀC40), 71.55 ꢀC50), 88.18 ꢀC10), 94.30 ꢀC5), 140.32 ꢀC4), 156.4 ꢀC6), 165.73 ꢀC2) ppm.
*1RS,2R,3S)-Tetrahydro-1,2-bis-acetoxy-3-***4-methoxyphenyl)-
diphenylmethoxy)-methyl)-furan ꢀ15; C29H30O7)
To a solution of the dihydrofuran 9b ꢀ150 mg, 0.40 mmol) in acetone ꢀ2 cm3), OsO4=t-BuOH solution
ꢀ0.16 cm3, prepared from OsO4 ꢀ60 mg, 0.24 mmol), t-BuOH ꢀ6 cm3), and 30% H2O2 ꢀ1 drop)) and 4-
methylmorpholine N-oxide ꢀNMO, 50% in H2O, 0.20 cm3, 1.0 mmol) were added at 0ꢀC, and the
mixture was stirred at the same temperature for 1.5 h. After the reaction was quenched with sat. aq.
NH4Cl, the mixture was extracted with CH2Cl2 and dried over MgSO4. After removal of the solvent,
the residue was puri®ed by ¯ash chromatography ꢀhexane:AcOEt 1:2) to give a mixture of the 1,2-
diols ꢀ165 mg, 100%). To a solution of this diol mixture ꢀ165 mg, 0.406 mmol) in CH2Cl2 ꢀ1.6 cm3),
NEt3 ꢀ0.41 cm3, 2.9 mmol), Ac2O ꢀ0.17 cm3, 1.4 mmol), and DMAP ꢀ3 mg, 0.025 mmol) were added
at room temperature, and the mixture was stirred at the same temperature for 22 h. After the reaction
was quenched with H2O, the mixture was extracted with CH2Cl2 and dried over MgSO4. After re-
moval of the solvent, the residue was puri®ed by ¯ash chromatography ꢀhexane:AcOEt 2:1) to give
the diacetates 15 and 16 ꢀ199 mg, 100%) as a 12:8:1 mixture of ꢀ1R,2R,3S)-, ꢀ1S,2R,3S )-, and
ꢀ1R,2S,3S )-isomers.
IR ꢀneat): ꢃ 2932, 1748, 1609, 1510, 1449, 1372, 1300, 1250, 1221, 1181, 1078, 1032, 961,
833, 700 cmÀ1; 1H NMR ꢀ400 MHz, CDCl3): ꢀ1R,2R,3S )-15: ꢄ 2.04 ꢀ3H, s), 2.08 ꢀ3H, s), 2.78 ꢀ1H,
m), 3.18 ꢀ1H, dd, J 9.2 and 6.4 Hz), 3.34 ꢀ1H, dd, J 9.2 and 6.9 Hz), 3.80 ꢀ3H, s), 3.8 ꢀ1H, m),
4.23 ꢀ1H, dd, J 8.7 and 6.7 Hz), 5.04 ꢀ1H, dd, J 8.8 and 4.2 Hz), 6.33 ꢀ1H, d, J 4.2 Hz), 6.85
ꢀ2H, m), 7.2±7.45 ꢀ12H, m) ppm; ꢀ1R,2R,3S )-15: ꢄ 1.91 ꢀ3H, s), 2.09 ꢀ3H, s), 2.61 ꢀ1H, m), 3.24
ꢀ2H, m), 3.79 ꢀ3H, s), 3.8 ꢀ1H, m), 4.28 ꢀ1H, dd, J 8.6 and 7.9 Hz), 5.15 ꢀ1H, d, J 2.5 Hz), 6.09
ꢀ1H, s), 6.85 ꢀ2H, m), 7.2±7.45 ꢀ12H, m) ppm; ꢀ1R,2S,3S )-15: ꢄ 1.87 ꢀ3H, s), 2.09 ꢀ3H, s), 2.78
ꢀ1H, m), 3.24 ꢀ2H, m), 3.79 ꢀ3H, s), 3.8 ꢀ1H, m), 4.28 ꢀ1H, dd, J 8.6 and 7.9 Hz), 5.35 ꢀ1H, d,
J 4.8 Hz), 6.07 ꢀ1H, s), 6.85 ꢀ2H, m), 7.2±7.45 ꢀ12H, m) ppm.
6-N-Benzoyl-9-**1R,2R,3S)-tetrahydro-2-acetoxy-3-***4-methoxyphenyl)-
diphenylmethoxy)-methyl)-1-furanyl)-9H-adenine ꢀ17; C39H35N5O6)
To a suspension of 6-benzoyl-adenine ꢀ25 mg, 0.10 mmol) in 1,2-dichloroethane ꢀ1 cm3), N,O-bis-
ꢀtrimethylsilyl)-acetamide ꢀ0.080 cm3, 0.32 mmol) was added, and the mixture was stirred under
re¯ux for 15 min. To the above solution, a mixture of 15 and 16 ꢀ21 mg, 0.034 mmol) in 1,2-
dichloroethane ꢀ0.2 cm3) and trimethylsilyl tri¯ate ꢀTMSOTf, 0.065 cm3) were added, and the
mixture was stirred under re¯ux for 1 h. After the reaction was neutralized with aq. KHCO3, the
mixture was extracted with CH2Cl2 and dried over MgSO4. After removal of the solvent, the residue
was puri®ed by ¯ash chromatography ꢀAcOEt) to give the acetate 17 ꢀ21 mg, 93%) and the
detritylated product ꢀ1.5 mg, 4%).
23
ꢀ À2ꢀ ꢀc 0.1, CHCl3); IR ꢀneat): ꢃ 1744, 1701, 1611, 1582, 1510, 1456, 1250, 1181,
D
1
1074, 1034, 812, 708 cmÀ1; H NMR ꢀ400 MHz, CDCl3): ꢄ 2.09 ꢀ3H, s), 2.87 ꢀ1H, m), 3.42 ꢀ1H,
dd, J 9 and 7.5 Hz), 3.46 ꢀ1H, dd, J 9 and 6.3 Hz), 3.79 ꢀ3H, s), 4.26 ꢀ1H, dd, J 8.8 and 8.4 Hz),
4.36 ꢀ1H, dd, J 8.8 and 7.8 Hz), 5.84 ꢀ1H, dd, J 5.8 and 3.6 Hz), 6.01 ꢀ1H, d, J 3.6 Hz), 6.83
ꢀ2H, m), 7.2±7.35 ꢀ8H, m), 7.42 ꢀ4H, m), 7.53 ꢀ2H, t, J 7.5 Hz), 7.61 ꢀ1H, d, J 7.5 Hz), 7.98 ꢀ1H,
s), 8.02 ꢀ1H, d, 7.5 Hz), 8.64 ꢀ1H, s), 8.95 ꢀ1H, br s) ppm; 13C NMR ꢀ100 MHz, CDCl3): ꢄ 20.74
ꢀCH3CO), 45.82 ꢀC30), 55.27 ꢀOCH3), 61.54 ꢀC40), 71.69 ꢀC20), 78.97 ꢀC50), 86.67 ꢀCAr3), 90.28
ꢀC10), 113.20 ꢀortho-C Â 2 of MeOAr), 124ꢀC5), 127.09 ꢀ2C of Ph), 127.87 ꢀ2C of Bz), 127.92 ꢀ4C
of Ph), 128.32 and 128.35 ꢀ4C of Ph), 128.85 ꢀ2C of Bz), 130.26 ꢀ2C of Ph), 132.74 ꢀ1C of Bz), 134