Glycosyl aldehyde

Although various chiral glycosyl aldehydes with a direct attachment of the carbonyl group to the anomeric center showed low diastereoselectivity [52], a moderate stereoselectivity was observed in the condensation of 45 with methyl isocyanoa-cetate, propionic acid and a solid-supported amine [53]. 

In an elegant and different approach, an array of C-linked, glycopeptide-like mimics of SLex were synthesized in parallel by an Ugi four-component reaction. Reaction of different anomeric two- or three-carbon extended C-glycosyl aldehydes or acids with resin-bound amine, isonitriles and with other acids or aldehydes, respectively, yielded an array of C-linked analogues. The method is easy to perform in good yield on solid phase. How-... 

Deoxygenation of allylic alcohols without affecting isolated tertiary alcohols, double bonds, and acetals is accomplished by reaction with EtsSiH in the presence of LiC104. A route to /3-C-glycosyl aldehydes involves reaction of sugar lactones with 2-lithio-l,3-dithiane, reduction with EtsSiH, and hydrolysis of the dithiane. ... 

This synthetic methodology has been used in the condensation of meso p-tolyl)pyrromethane with glycosylated aldehydes (Scheme 24), to give rise to porphyrins 124 [128-130]. 

Sialyl Le /is -related selectin inhibitor by chain extension of C-glycosyl aldehydes using enzymatic aldolization, and multienzymatic oxidation-aldolization strategy for synthesis of bicyclic higher-carbon sugars. 

SCHEME 1.1 Three-component Hantzsch reaction of a chiral C-glycosyl aldehyde. 

SCHEME 1.4 Three-component Mannich reactions of chiral C-glycosyl aldehydes. 

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