ABSTRACT
Fischer Glycosylation ................................................................. 125
4.3.3.4.2 Activation via Glycosyl Halides ................................................ 126
4.3.3.4.3 Activation via Glycosyl Sulfonates ............................................ 127
4.3.3.4.4 Activation via Oxophosphonium Intermediates ......................... 127
4.3.3.4.5 Activation via Oxosulfonium
Intermediates ............................................................................... 128
4.3.3.4.6 Activation with Lewis Acids ...................................................... 128
4.3.3.4.7 Other Methods of Activation ...................................................... 129
4.3.3.5 1,2-Anhydro Derivatives ............................................................................ 130
4.3.3.6 Glycosyl Phosphites, Phosphates and Other Phosphorus
Compounds ................................................................................................. 131
4.3.3.6.1 Glycosyl Phosphites .................................................................... 131
4.3.3.6.2 Glycosyl Phosphates ................................................................... 132
4.3.3.6.3 Other Phosphorus Compounds ................................................... 133
4.3.3.7 Orthoesters and Related Derivatives .......................................................... 133
4.3.3.8 Carbonates and Related Derivatives .......................................................... 138
4.3.3.9 Silyl Ethers .................................................................................................. 140
4.3.3.10 Oxazolines ................................................................................................... 141
4.3.3.11 Other Glycosyl Donors with Glycosyl-Oxygen Bonds ............................ 142
4.3.4 Synthesis of Glycosides from Donors with Other Heteroatoms
at the Anomeric Center ............................................................................................. 142
4.3.4.1 Selenoglycosides and Telluroglycosides ...................................................... 142
4.3.4.2 Glycosyl Donors with Nitrogen at the Anomeric Center ............................ 143
4.4 Glycosylations by Nucleophilic Substitution at the Aglycone Carbon .............................. 144
4.5 Synthesis of Glycosides by Addition Reactions ................................................................. 146
4.6 Other Glycosylation Methods ............................................................................................. 149
4.7 Summary and Outlook ......................................................................................................... 150
References ................................................................................................................................... 151
In the overwhelming majority of carbohydrates found in nature, the carbohydrates do not occur in a
free form, but the monosaccharides are linked to each other or to other types of compounds
(aglycones) by glycosidic bonds. Compounds possessing O-(1), S-(2), or N-glycosidic linkages (3)
(Figure 4.1) occur in nature. Among them, O-glycosidic compounds are the most abundant and
important. As such, this chapter focuses on the preparation of O-glycosides.
