770
3
Chemical Glycosylation Reactions
⊡ Scheme 18
⊡ Table 5
[32]
Carbohydrate
Acetylene
Conditions
Products
Ref.
R 1
R 2
X
R
Lewis acid, solvent
R
Yield (%)
Glc OBn
OBn
OBn
N 3
N 3
Bn
Ac
Bn
Bn
Ac
Br
Cl
OAc
OAc
Br
Ph
Ph
TMS
TMS
C 6 H 13
ZnCl 2 , CCl 4
AgBF 4 , (CH 2 Cl) 2
TMSOTf, CH 2 Cl 2
TMSOTf, CH 2 Cl 2
AgBF 4 , (CH 2 Cl) 2
Ph
Ph
H
TMS
C 6 H 13
61
73
71 a
43
76
[32a]
[32b]
[32c]
[32d]
[32b]
Man OBn
OBn
N 3
Ac
Bn
Bn
OAc
OAc
OAc
TMS
TMS
TMS
TMSOTf, CH 2 Cl 2
TMSOTf, CH 2 Cl 2
TMSOTf, CH 2 Cl 2
H
H
TMS
83 a
65 a
35
[32c]
[32c]
[32d]
Gal OBn
N 3
Bn
Bn
OAc
OAc
TMS
TMS
TMSOTf, CH 2 Cl 2
TMSOTf, CH 2 Cl 2
H
TMS
54 a
63
[32c]
[32d]
a : The yields after desilylation with TBAF in THF or K 2 CO 3 in MeOH
⊡ Table 6
[33]
Entry
Carbohydrate
Acetylene
Conditions
Yield (%)
Ref.
R 1
R 2
R 3
X
R 4
Lewis acid, solvent
1
OAc
OAc
Ac
OAc
TMS
SnCl 4 , CH 2 Cl 2
73
[33a]
2
H
OAc
Ac
OAc
SPh
BF 3 ·OEt 2 , CH 3 CN
72
[33b]
3
OAc
OAc
Ac
OAc
SnCl 4 , CH 2 Cl 2
71
[33a]
4
OAc
OAc
Ac
OAc
SnCl 4 , CH 2 Cl 2
83
[33a]
5
M e
H
T B D P S
O i-Pr
SPh
BF 3 ·OEt 2 , CH 3 CN
61
[33c]
6
H
M e
H
O E t
S P h
B F 3 ·OEt 2 , CH 3 CN
62
[33d]