662
3
Chemical Glycosylation Reactions
3.2.4 Synthesis of Non-Reducing Sugars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 691
3.2.5 Enzymatic Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 691
3.3
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 693
Abstract
Published methods to synthesize thioglycosides have been reviewed. Two major pathways
are recognized, either a displacement of an anomeric leaving group with a thiol acceptor to
give the thioglycoside directly, or an initial formation of an anomeric thiol, which then is
alkylated to give the thioglycoside. For the direct approach a listing is made based on the
diverse anomeric leaving groups that have been utilized, acetates and halides being the most
common. For the second pathway, various ways to form an anomeric thiol in a stereoselective
manner are summarized, hydrolysis of anomeric thioacetates or pseudothiouronium salts being
the most frequent, as well as different methodologies to perform the subsequent alkylation or
arylation. Some miscellaneous pathways to thioglycosides, mainly through rearrangement of
special O-glycosyl derivatives, are also discussed. In the last part an overview of the use of the
discussed methodologies in the synthesis of thiooligosaccharides, i. e. oligosaccharides with
interglycosidic thiolinkages, is presented.
Keywords
Thioglycosylation; Thioglycosides; Thiosaccharides; Synthesis
Abbreviations
AIBN azobisisobutyronitrile
CAN
ceric ammonium nitrate
DMF
dimethylformamide
DTT
dithiothreitol
HMPA hexamethylphosphoramide
IDCP
iodonium dicollidine perchlorate
Kdo
3-deoxy-D-manno-2-octulosonic acid
mCPBA meta-chloroperoxybenzoic acid
NIS
N-iodosuccinimide
OTMS octadecyltrimethoxysilane
TFA
trifluoroacetic acid
TMSO N-trimethylsilyl-2-oxazolidinone
UDP
uridine diphosphate
1 Introduction
Carbohydrate derivatives with anomeric sulfur are not very common in nature, the only examples found are the various glucosinolates (“mustard oil glycosides”) mainly from the Brassicaceae family [1,2,3], the simple alkyl thioglycosides of lincomycin and structurally relat-
3
Chemical Glycosylation Reactions
3.2.4 Synthesis of Non-Reducing Sugars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 691
3.2.5 Enzymatic Synthesis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 691
3.3
Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 693
Abstract
Published methods to synthesize thioglycosides have been reviewed. Two major pathways
are recognized, either a displacement of an anomeric leaving group with a thiol acceptor to
give the thioglycoside directly, or an initial formation of an anomeric thiol, which then is
alkylated to give the thioglycoside. For the direct approach a listing is made based on the
diverse anomeric leaving groups that have been utilized, acetates and halides being the most
common. For the second pathway, various ways to form an anomeric thiol in a stereoselective
manner are summarized, hydrolysis of anomeric thioacetates or pseudothiouronium salts being
the most frequent, as well as different methodologies to perform the subsequent alkylation or
arylation. Some miscellaneous pathways to thioglycosides, mainly through rearrangement of
special O-glycosyl derivatives, are also discussed. In the last part an overview of the use of the
discussed methodologies in the synthesis of thiooligosaccharides, i. e. oligosaccharides with
interglycosidic thiolinkages, is presented.
Keywords
Thioglycosylation; Thioglycosides; Thiosaccharides; Synthesis
Abbreviations
AIBN azobisisobutyronitrile
CAN
ceric ammonium nitrate
DMF
dimethylformamide
DTT
dithiothreitol
HMPA hexamethylphosphoramide
IDCP
iodonium dicollidine perchlorate
Kdo
3-deoxy-D-manno-2-octulosonic acid
mCPBA meta-chloroperoxybenzoic acid
NIS
N-iodosuccinimide
OTMS octadecyltrimethoxysilane
TFA
trifluoroacetic acid
TMSO N-trimethylsilyl-2-oxazolidinone
UDP
uridine diphosphate
1 Introduction
Carbohydrate derivatives with anomeric sulfur are not very common in nature, the only examples found are the various glucosinolates (“mustard oil glycosides”) mainly from the Brassicaceae family [1,2,3], the simple alkyl thioglycosides of lincomycin and structurally relat-