572
3
Chemical Glycosylation Reactions
⊡ Table 1
Oxidative hydrolysis of some NPGs with NBS in 1% aqueous acetonitrile
Substrate
Product
Yield (%)
85
70
90
68
63
72
complex mixture
⊡ Table 2
Reaction of NPG 12 with methanol in the presence of halonium ions
Entry Promoter
Time (h) Solvent
α:β
Yield (%)
I
NBS
3
MeCN
1:3 85
ii
I(collidine) 2 ClO 4
0,5
MeCN
1:3 75
iii
I(collidine) 2 ClO 4
0,5
CH 2 Cl 2
1.2:1 85
iv
I(collidine) 2 ClO 4
24
CH 2 Cl 2 -Et 2 O
3:1 75
3
Chemical Glycosylation Reactions
⊡ Table 1
Oxidative hydrolysis of some NPGs with NBS in 1% aqueous acetonitrile
Substrate
Product
Yield (%)
85
70
90
68
63
72
complex mixture
⊡ Table 2
Reaction of NPG 12 with methanol in the presence of halonium ions
Entry Promoter
Time (h) Solvent
α:β
Yield (%)
I
NBS
3
MeCN
1:3 85
ii
I(collidine) 2 ClO 4
0,5
MeCN
1:3 75
iii
I(collidine) 2 ClO 4
0,5
CH 2 Cl 2
1.2:1 85
iv
I(collidine) 2 ClO 4
24
CH 2 Cl 2 -Et 2 O
3:1 75