432
3
Chemical Glycosylation Reactions
⊡ Table 3
Glycosylation of glycosyl bromide or chloride using phase transfer catalyst
Catalyst
Conditions
Ref.
Et 3 N + BnBr −
CHCl 3 /H 2 O/NaOH
[23]
Et 3 N + BnCl −
CH 2 Cl 2 /H 2 O/NaOH or KOH
[24]
Me(CH 2 ) 15 N + Me 3 Br −
CH 2 Cl 2 /H 2 O/NaOH
[25,26]
Bu 4 N + Br −
CH 2 Cl 2 /H 2 O/NaOH
[27]
Bu 4 N + HSO
−
4
CH 2 Cl 2 /H 2 O/NaOH or NaHCO 3
[28]
Aliquat ® 336 (R = alkyl) CH 2 Cl 2 /H 2 O/K 2 CO 3
[29]
BnN + Bu 3 Cl −
CHCl 3 /H 2 O/K 2 CO 3
[30]
⊡ Scheme 1
⊡ Scheme 2
IBr [13], NIS [14], In [15], InCl 3 [16], TMSOTf [17], (C 4 H 8 N) 3 P = O [18,19], Zn(acac) 2 [20],
(t-BuC 6 H 4 CO 2 ) 2 Zn [21], and Cu(OTf) 2 -BTF [22] were reported in this field ( > Table 2).
The glycosylations of aryl alcohols using a phase transfer catalyst such as Et 3 N + BnBr −
[23a, b], Et 3 N + BnCl − [24], Me(CH 2 ) 15 N + Me 3 Br − [25,26], Bu 4 N + Br − [27], Bu 4 NH + SO 4
−
[28], Aliquat ® 336 [29], and BnN + Bu 3 Cl − [30] were also developed ( > Table 3).