7932
M. G. B. Drew et al. / Tetrahedron 57 -2001) 7919±7937
anhydrous solution of Et2O/CH2Cl2 >1:1, 4 cm3), silver
tri¯ate >156 mg, 0.60 mmol, 3 equiv.), phenylsulfenyl
chloride >73 mg, 0.50 mmol, 2.5 equiv.) in anhydrous
dichloromethane >2 cm3), donor >7) >100 mg, 2.0 mmol)
and DTBMP >124 mg, 0.61 mmol, 3 equiv.) in anhydrous
Et2O/CH2Cl2 >1:2, 2 cm3), acceptor >20) >98 mg, 0.25 mmol,
1.25 equiv.) in anhydrous Et2O/CH2Cl2 >1:2, 1.5 cm3) were
149 >22), 131 >19), 105 >100), 93 >44), 91 >19), 85 >21), 77
>26), 57 >39), 43 >15), 41 >21), 39 >31).
4.4.3. Benzyl 2-deoxy-N-acetyl-3-O-benzyl-4-[2-deoxy-2-
5O-pivaloyl)oximino-3-O-pivaloyl-4,6-O-benzylidene-1-
a/b-d-glucopyranoside]-1-O-a-d-glucopyranoside 526a,
26b). Following method A detailed above, and using
anhydrous dichloromethane as solvent, donor >7) >75 mg,
0.152 mmol), acceptor >22) >68 mg, 0.152 mmol, 1.0
equiv.), NIS >47 mg, 0.192 mmol, 1.26 equiv.), TfOH
>6.7 ml, 0.08 mmol, 0.5 equiv.) were reacted and quenched
and worked up as outlined above then submitted to column
chromatography >1:1 cyclohexane/ethyl acetate, with 1%
TEA as co-solvent). Evaporation of pure fractions of the
major product afforded a-disaccharide >26a) >40 mg,
30%) as a clear oil. Evaporation of the fractions containing
both disaccharide anomers afforded a 1:1 ratio of >26a/26b)
>25 mg, 19%,) as a clear oil. Finally, evaporation of the
following fractions afforded b-disaccharide >26b) >9 m g,
7%, total yield 74 mg, 57%,) as a clear oil. For >26a).
1
reacted and worked up as outlined above. H NMR of the
crude mixture showed ,1:3 >24a,24b). The mixture was
submitted to column chromatography, using ®ne grade
silica gel >5:1 hexane/ethyl acetate then 3.5:1 hexane/ethyl
acetate, with 1% TEA). Evaporation of pure fractions of the
minor product afforded a-disaccharide >24a). >25 mg, 17%)
as a foam. Evaporation of the remaining fractions contain-
ing disaccharide products afforded a mixture of $11:1 of
disaccharides >24b,24a). >75 mg, 54%) as a foam. For
>24a). [a]D 61.3 >c 0.15 in CHCl3); nmax >nujol)/cm21
20
3120 w, 3085 mand 3060 m>C±H), 1782 s, and 1755 s
>CvO), 1615 s, 1602 mand 1500 m>C vC), 1325 s and
1295 m>C±H), 1240 s, 1222 s, 1180 m, 1138 s, 1105 s, 1090
s and 1038 s >C±O), 745 s and 705 s >Ar); dH >250 MHz;
CDCl3) 0.80 >9H, s, >CH3)3CCO), 1.21 >9H, s, >CH3)3CCO),
2.10 >3H, s, CH3CO), 3.66±3.85 >3H, m, H-5, H-40, H-60),
3.89±4.05 >2H, m, H-6, H-4), 4.10 >1H, dd, J5.0, 10.0 Hz,
H-6), 4.32±4.46 >2H, m, H-60, H-50), 4.56 >1H, t, J9.5 Hz,
H-30), 4.94 >1H, dd, J4.0, 9.5 Hz, H-20), 5.48 >1H, s,
PhCH), 5.53 >1H, s, PhCH), 5.69 >1H, d, J4.0 Hz, H-10),
5.78 >1H, d, J10.5 Hz, H-3), 6.26 >1H, s, H-1), 6.94±7.36
>15H, m, Ar); dC >62.5 MHz; CDCl3) 21.23 >CH3CO), 27.11
>>CH3)3CCO), 27.46 >>CH3)3CCO), 38.52 >>CH3)3CCO),
39.31 >>CH3)3CCO), 63.30, 63.82 >C-50, C-5), 68.79,
68.94, 69.01 >C-3, C-6, C-60), 72.04, 72.15 >C-20, C-30),
80.09, 81.82 >C-40, C-4), 92.29 >C-1), 95.47 >C-10),
101.76, 102.02 >PhCH0, PhCH), 117.19, 123.49, 126.28,
126.65, 128.69, 128.76, 129.52, 129.61, 130.11, 137.20
>>2£Ar{C-1}), >3£Ar{C-4}), >3£Ar{C-2, C-6}), >3£
Ar{C-3, C-5})), 155.12, 156.57 >C-2, PhO{C-1}), 170.44
>CH3CO), 173.91, >>CH3)3CCO) 177.65, >>CH3)3CCO); >CI:
Found [M1NH4]1, 835.3616, C44H55N2O14 requires
[M1NH4]1, 835.3653); m/z >CI) 835 >[M1NH4]1, 8%),
724 >14), 711 >8), 415 >15), 321 >18), 263 >23), 149 >25),
105 >100), 93 >51), 85 >33), 77 >27), 57 >65), 43 >15), 41
[a]D 124.9 >c 0.45 in CHCl3); nmax >nujol)/cm21 3115
20
w, 3085 mand 3050 m>C±H), 1740 s, and 1680 s
>CvO), 1620 w, 1595 mand 1507 m>C vC), 1460 s and
1445 m>C±H), 1375 s, 1340 m, 1270 br, 1145 s, 1120 s,
1040 br and 920 s >C±O), 740 s and 700 s >Ar); dH
>600 MHz; CDCl3) 1.05 >9H, s, >CH3)3CCO), 1.30 >9H, s,
>CH3)3CCO), 1.79 >3H, s, CH3CO), 2.10 >3H, s, CH3CO),
3.68 >1H, dd, J9.0, 10.5 Hz, H-30), 3.77 >1H, t, J10.5 Hz,
H-6), 3.81 >1H, app. t, J9.0, 9.5 Hz, H-40), 3.92 >1H, dd,
J3.0, 10.0 Hz, H-50), 4.01 >1H, t, J10.0 Hz, H-4), 4.20±
4.24 >3H, m, H-60, H-2, H-5), 4.40±4.47 >4H, m, H-60, H-6,
PhCH2), 4.68 >2H, dd, J9.5, 11.5 Hz, PhCH2), 4.88 >1H, d,
J3.5 Hz, H-10), 5.22 >1H, d, J9.0 Hz, NH), 5.59 >1H, s,
PhCH), 5.97 >1H, d, J10.5 Hz, H-3), 6.09 >1H, s, H-1),
7.22±7.48 >15H, m, Ar); dC >150 MHz; CDCl3) 20.71
>CH3CO), 23.26 >CH3CO), 26.94 >>CH3)3CCO), 27.09
>>CH3)3CCO), 38.50 >>CH3)3CCO), 38.93 >>CH3)3CCO),
52.36 >C-20), 63.14 >C-60), 64.59 >C-5), 68.25 >C-6), 68.48
>C-3), 69.00 >C-50), 70.05 >PhCH2), 74.97 >PhCH2), 78.50,
>C-30), 79.71 >C-4), 83.71 >C-40), 95.42 >C-1), 96.88 >C-10),
101.34 >PhCH), 125.98, 127.62, 128.02, 128.24, 128.31,
128.46, 128.67, 129.11, 136.74, 136.77 138.20 >>3£Ar{C-
1}), >3£Ar{C-4}), >3£Ar{C-2, C-6}), >3£Ar{C-3, C-5})),
155.16 >C-2), 169.80 >CH3CO), 170.51 >CH3CO), 173.24,
>>CH3)3CCO) 177.31, >>CH3)3CCO); >CI: Found [M]1,
874.3852, C47H58N2O14 requires [M]1, 874.3888); m/z
>CI) 874 >[M]1, 1%), 773 >1), 528 >16), 444 >100), 336
>32), 228 >11), 105 >14), 91 >80), 85 >16), 57 >23), 41
20
>22), 39 >32). For >24b). [a]D 49.0 >c 0.6 in CHCl3); dH
>250 MHz; CDCl3) 1.19 >9H, s, >CH3)3CCO), 1.24 >9H, s,
>CH3)3CCO), 1.98 >3H, s, CH3CO), 3.48±3.76 >4H, m, H-6,
H-5, H-40, H-60), 3.98±4.16 >2H, m, H-50, H-6), 4.17 >1H,
dd, J5.0, 10.0 Hz, H-60), 4.45±4.59 >2H, m, H-4, H-30),
4.62 >1H, s, PhCH), 4.89 >1H, dd, J3.5, 9.5 Hz, H-20), 5.52
>1H, s, PhCH), 5.72 >1H, d, J3.5 Hz, H-10), 5.81 >1H, d,
J8.5 Hz, H-3), 6.09 >1H, s, H-1), 6.94±7.46 >15H, m,
Ar); dC >62.5 MHz; CDCl3) 21.46 >CH3CO), 27.45
>>CH3)3CCO), 27.66 >>CH3)3CCO), 39.11 >>CH3)3CCO),
39.21 >>CH3)3CCO), 63.69 >C-50), 67.00 >C-5), 68.92
>C-3), 69.16, 69.41 >C-6, C-60), 73.84 >C-20), 74.33 >C-30),
76.74 >C-4), 80.61 >C-40), 91.96 >C-1), 95.15 >C-10), 100.77,
102.74 >PhCH0, PhCH), 116.96, 123.50, 126.33, 126.62,
128.40, 128.83, 129.21, 130.16, 137.20 >>2£Ar{C-1}),
>3£Ar{C-4}), >3£Ar{C-2, C-6}), >3£Ar{C-3, C-5})),
156.55, 157.44 >C-2, PhO{C-1}), 170.47 >CH3CO),
173.97, >>CH3)3C CO) 177.03, >>CH3)3CCO); >CI: Found
[M]1, 817.3316, C44H51NO14 requires [M]1, 817.3309);
m/z >CI) 817 >[M]1, 1%), 724 >[M2OPh]1, 2), 716 >5),
622 >3), 415 >13), 348 >20), 241 >28), 321 >16), 241 >28),
25
>10), 39 >10). For >26b). [a]D 24.7 >c 0.45 in CHCl3);
n
max >nujol)/cm21 3310 w >N±H), 3110 w, 3085 w and 3060
m>C±H), 1780 s, 1750 s and 1675 s >C vO), 1550 mand
1510 m>C vC), 1490 s >C±H), 1320 m, 1285 m, 1240 s,
1120 s, 1090 br and 1045 br >C±O), 760 mand 710 m>Ar);
d
H >600 MHz; CDCl3) 1.23 >9H, s, >CH3)3CCO), 1.24 >9H,
s, >CH3)3CCO), 1.83 >3H, s, CH3CO), 2.06 >3H, s, CH3CO),
3.64±3.72 >2H, m, H-5, H-6), 3.76±3.80 >1H, m, H-30),
3.89±3.92 >2H, m, H-40, H-50), 4.12±4.15 >1H, m, H-60),
4.27 >1H, dd, J4.0, 9.0 Hz, H-6) 4.35 >1H, dt, J3.5,
10.0 Hz, H-20), 4.44±4.49 >2H, m, H-4, PhCH2), 4.54 >1H,
d, J11.5 Hz, H-60), 4.68±4.72 >2H, m, PhCH2), 4.84 >1H,
d, J3.5 Hz, H-10), 4.84 >1H, d, J10.5 Hz, PhCH2), 5.25
>1H, s, PhCH), 5.42 >1H, d, J9.5 Hz, NH), 5.98 >1H, d,
J9.0 Hz, H-3), 6.23 >1H, s, H-1), 7.29±7.42 >15H,