588
3
Chemical Glycosylation Reactions
⊡ Scheme 17
Semi-orthogonality of O-pentenyl and S-ethyl-glycosides
could be activated in the presence of thioglycosides (e. g. 131) with IDCP as the promoter
( > Scheme 17a). On the other hand, the use of methyl triflate (MeOTf) permitted the activation of disarmed thioglycosides (e. g. 133b) in the presence of armed or disarmed NPGs, 134
( > Scheme 17b).
2.7.2 Semi-Orthogonality of NPGs and Glycosyl Fluorides
López et al. reported the selective activation of armed NPGs (e. g. 136) in the presence of
armed glycosyl fluorides (e. g. 137) on treatment with IDCP ( > Scheme 18a) [49]. On the
other hand, armed and disarmed glycosyl fluorides 139, could be activated in the presence of
armed NPGs (e. g. 140) on treatment with ytterbium triflate (Yb(OTf) 3 ) ( > Scheme 18b).
⊡ Scheme 18
Semi-orthogonality of NPGs and glycosyl fluorides
3
Chemical Glycosylation Reactions
⊡ Scheme 17
Semi-orthogonality of O-pentenyl and S-ethyl-glycosides
could be activated in the presence of thioglycosides (e. g. 131) with IDCP as the promoter
( > Scheme 17a). On the other hand, the use of methyl triflate (MeOTf) permitted the activation of disarmed thioglycosides (e. g. 133b) in the presence of armed or disarmed NPGs, 134
( > Scheme 17b).
2.7.2 Semi-Orthogonality of NPGs and Glycosyl Fluorides
López et al. reported the selective activation of armed NPGs (e. g. 136) in the presence of
armed glycosyl fluorides (e. g. 137) on treatment with IDCP ( > Scheme 18a) [49]. On the
other hand, armed and disarmed glycosyl fluorides 139, could be activated in the presence of
armed NPGs (e. g. 140) on treatment with ytterbium triflate (Yb(OTf) 3 ) ( > Scheme 18b).
⊡ Scheme 18
Semi-orthogonality of NPGs and glycosyl fluorides