Prearranged Glycosides, Part 12, Intramolecular Mannosylations of ...

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Helvetica Chimica Acta ± Vol. 83 2000)
5.61 br. d, H C2')); 5.51 d, J1,2) ˆ 1.5, H C1')); 5.28 d, J1,2) ˆ 3.7, H C1)); 5.00 dd, J2,3) ˆ 10.3,
H C2)); 4.87 d, J ˆ 10.8, 1 H, PhCH 2); 4.78 d, J ˆ 12.4, 1 H, PhCH 2); 4.68 d, J ˆ 11.2, 1 H, PhCH 2);
4.65± 4.63 m, 2 H, PhCH 2); 4.63 d, J ˆ 10.5, 1 H, PhCH 2); 4.56 d, J ˆ 12.2, 1 H, PhCH 2); 4.52 d, J ˆ
11.0, 1 H, PhCH 2); 4.50 d, J ˆ 10.8, 1 H, PhCH 2); 4.43 d, J ˆ 11.9, 1 H, PhCH 2); 4.32 ddd, J5',6a') ˆ 4.3,
J5',6b') ˆ 1.8, H C5')); 4.01 ± 3.91 m, H C3'), H C4'), H C5)); 3.84 dd, J6a',6b') ˆ 10.8,
H a C6')); 3.80 ± 3.72 m, H C4), H a C6), H b C6)); 3.70 dd, H b C6')); 3.33 br. s, OH); 2.81 ± 2.44
m, COCH 2CH 2CO). 13 C-NMR CDCl 3): 172.2, 171.3 COCH 2CH 2CO); 165.7 PhCO); 95.2 C1)); 85.6
C1')); 78.3 C3')); 75.2 PhCH 2); 74.3 C4')); 73.6 PhCH 2); 73.5C3)); 73.3 PhCH 2); 72.3 C5')); 71.8
PhCH 2); 71.4 C2)); 70.5C2')); 70.4 C5)); 69.5 C4), PhCH 2); 69.2 C6)); 68.6 C6')); 29.3, 29.1
COCH 2CH 2CO). Anal. calc. for C 64H 64O 14S 1089.27): C 70.57, H 5.92; found: C 70.44, H 5.98.
Benzyl 2-O-Benzoyl-6-O-benzyl-3-O-[4-ethyl 3,4,6-tri-O-benzyl-1-thio-a-d-mannopyranosid-2-O-yl)-1,4dioxobutyl]-a-d-glucopyranoside
5b). As described for 5a, with 4b 0.52 g, 0.5 mmol) and NaCNBH 3 0.29 g,
4.64 mmol): 5b 0.46 g, 88%). [a] D ˆ‡86.2 c ˆ 1.3, CHCl 3). 1 H-NMR CDCl 3): 5.98 dd, J2,3) ˆ 10.1, J3,4) ˆ
9.2, H C3)); 5.43 dd, J1,2) ˆ 1.5, J2,3) ˆ 2.4, H C2')); 5.25 ± 5.21 m, H C1), H C1')); 5.00 ± 4.38
m, 11H, H C2), PhCH 2), 3.88 ddd, J5',6a') ˆ 1.8, J5',6b') ˆ 3.3, H C5')); 3.89 ± 3.76 m, H C3'),
H C4'), H C5)); 3.66 dd, J6a',6b') ˆ 10.7, H a C6')); 4.99 dd, J5,6a) ˆ 3.7, J6a,6b) ˆ 10.3,
H a C6)); 3.85± 3.79 m, H b C6)); 3.74 dd, J6a',6b') ˆ 10.7, H b C6')); 3.45s, OH); 2.78±2.36
m, COCH 2CH 2CO); 1.28 t, Me). 13 C-NMR CDCl 3; significant signals): 95.2 C1)); 82.4 C1')); 78.3
C3')); 74.4 C4')); 71.7 C5')); 70.7 C2')); 69.4 C2)); 69.3 C6)); 68.6 C6')); 29.4, 29.3 COCH 2CH 2-
CO); 25.7 CH 2S); 14.9 Me). Anal. calc. for C 60H 64O 14S 1041.22): C 69.21, H 6.20, S 3.08; found: C 69.00,
H 6.33, S 3.25.
Benzyl O-3,4,6-Tri-O-benzyl-a-d-mannopyranosyl)-1 ! 4)-2-O-benzoyl-6-O-benzyl-a-d-glucopyranoside
2',3-Succinate 6). a) A suspension of 5a 0.64 g, 0.59 mmol) and 3-Š molecular sieves ca. 0.2 g) in
CH 2Cl 2 20 ml) was stirred under Ar for 20 min at r.t. and cooled to 308. NIS 0.66 g, 2.94 mmol) and
Me 3SiOTf 27 ml, 0.15mmol) were added, and the mixture was stirred for 5min. The reaction was quenched by
addition of pyridine, the mixture warmed to r.t., diluted with CH 2Cl 2 and filtered, and the filtrate washed with
aq. NaHCO 3 and Na 2S 2O 3 soln., dried, and evaporated. CC toluene/acetone 18 :1) of the residue afforded 6
0.41 g, 71%). [a] D ˆ‡128.4 c ˆ 1.0, CHCl 3). 1 H-NMR CDCl 3): 5.80 dd, J3,4) ˆ 9.2, H C3)); 5.24
d, J1,2) ˆ 3.7, H C1)); 5.11 br. s, H C1')); 5.04 dd, J2,3) ˆ 10.5, H C2)); 4.82 dd, J2',3') ˆ 2.9,
H C2')); 4.73 d, J ˆ 12.4, 1 H, PhCH 2); 4.63 d, J ˆ 11.7, 1 H, PhCH 2); 4.53 d, J ˆ 12.2, 1 H, PhCH 2);
4.54 ± 4.51 m, 1 H, PhCH 2); 4.46 d, J ˆ 10.4, 1 H, PhCH 2); 4.42 s, 2 H, PhCH 2); 4.40 d, J ˆ 12.3, 1 H,
PhCH 2); 4.37 d, J ˆ 12.1, 1 H, PhCH 2); 4.26 d, J ˆ 11.8, 1 H, PhCH 2); 4.12 br. d, H C3')); 4.05± 3.96
m, H C5)), H C5')); 3.89 t, J4,5) ˆ 9.4, H C4)); 3.79 ± 3.69 m, 2H C6')); 3.77 br. d, H C4')); 3.56
br. d, H C6)); 3.49 br. t,H b C6)); 2.86 ± 2.37 m, COCH 2CH 2CO). 13 C-NMR CDCl 3): 172.7, 170.0
COCH 2CH 2CO); 165.7 PhCO); 102.4 J1', H C1')) ˆ 170.6, C1')); 94.9 C1)); 80.0 C3')); 75.6 C4));
74.9 C4')); 73.9 C2)); 73.0 PhCH 2); 72.9 PhCH 2); 72.7 C5')); 72.4 PhCH 2); 71.8 C5)); 71.3 PhCH 2,
C3)); 70.2 C2')); 69.7 PhCH 2); 69.4 C6)); 68.3 C6')); 31.2, 30.0 COCH 2CH 2CO). Anal. calc. for
C 58H 58O 14 979.10): C 71.15, H 5.97; found: C 71.29, H 6.02.
b) Exactly as described in Exper. a, with 5a 0.95g, 0.87 mmol), NIS 0.99 g, 2.94 mmol), Me 3SiOTf 40 ml,
0.22 mmol), and MeCN 30 ml): 6 0.63 g, 73%).
c) Exactly as described in Exper. a, with 5b 0.63 g, 0.62 mmol), NIS 0.67 g, 3.0 mmol), Me 3SiOTf 27 ml,
0.15mmol), and MeCN 100 ml): 6 0.33 g, 45%).
Benzyl O-2-O-Benzoyl-3,4,6-tri-O-benzyl-a-d-mannopyranosyl)-1 ! 4)-2,3-di-O-benzoyl-6-O-benzyl-ad-glucopyranoside
7). A soln. of 6 122 mg, 0.115mmol) and a cat. amount of NaOMe in MeOH 5ml) were
stirred for 24 h at r.t. Then, the mixture was neutralized with ion-exchange resin H ‡ form) and evaporated, the
residue dissolved in pyridine 3 ml), BzCl 70 ml, 0.6 mmol) added, and the mixture stirred at r.t. for 24 h, then
poured into H 2O, and extracted with CH 2Cl 2. The extracts were washed with aq. HCl and NaHCO 3 soln., dried
and evaporated. CC hexane/AcOEt 5: 1) of the residue afforded 7 82 mg, 64%). [a] D ˆ‡60.3 c ˆ 1.4,
CHCl 3). 1 H-NMR CDCl 3): 6.10 t, J3,4) ˆ 10.0, H C3)); 5.60 t, J2',3') ˆ 2.5, H C2')); 5.50 d, J1',2') ˆ
1.9, H C1')); 5.13 d, J1,2) ˆ 3.7, H C1)); 5.07 dd, J2,3) ˆ 9.9, H C2)); 4.88 d, J ˆ 10.9, PhCH 2); 4.74
d, J ˆ 11.7, 1 H, PhCH 2); 4.64 d, J ˆ 12.1, 1 H, PhCH 2); 4.61 d, J ˆ 12.2, 1 H, PhCH 2); 4.57 d, J ˆ 11.5,
1 H, PhCH 2); 4.56 d, J ˆ 11.2, 1 H, PhCH 2); 4.55 d, J ˆ 10.9, 1 H, PhCH 2); 4.50 ± 4.47 m, 3 H, PhCH 2);
4.21 t, J4,5) ˆ 10.1, H C4)); 4.07 dd, J3',4') ˆ 9.5, H C3')); 4.00 ± 3.93 m, H C4'),H C5'),H C5));
3.73 br. d, 2H C6')); 3.66 br. t, 2H C6)). 13 C-NMR CDCl 3): 166.3, 166.1, 165.7 PhCO); 97.8 J1'),
H C1') ˆ 175.5, C1')); 95.3 C1)); 77.9 C3')); 75.1 PhCH 2); 74.6 C3)); 74.2 C4')); 73.9 C4)); 73.4