Glycosyl phosphates oligosaccharides

Solid-Phase Oligosaccharide Synthesis Using Glycosyl Phosphates... 

Special Applications of Glycosyl Phosphates in Oligosaccharide Synthesis... 

The phytoalexin elicitor (PE) family of /1-D-glucans (Fig. 5) was selected as a target because these oligosaccharides had been synthesized previously in solution48,49 and on the solid support.50,51 It was our intention to investigate not only the application of glycosyl phosphates to automated solid-phase synthesis, but also to compare our method to the previously described reports of PE syntheses. 

An important class of naturally occurring anions are the nucleoside phosphates (i.e. nucleotides) present in nucleic acids, sugar nucleotides for glycosylation of oligosaccharides or proteins, activated forms of proteins and chemical mediators which play a central role in intracellular signals. Artificial phosphate receptors allow for detection and separation of biologically important compounds. However, most chemical receptors are soluble in solution and cannot be therefore separated easily from the solution binding the desired compound. 

Plante OJ, Andrade RB, Seeberger PH. Synthesis and use of gly-cosyl phosphates as glycosyl donors. Org. Lett. 1999 1 211-214. Plante OJ, Palmacci ER, Andrade RB, Seeberger PH. Oligosaccharide synthesis with glycosyl phosphate and dithiophosphate triesters as glycosylating agents. J. Am. Chem. Soc. 2001 123 9545-9554. 

Most frequently, diphenyl and di-n-butyl phosphates are used. As such, Singh and coworkers [471-474] introduced the cyclic propane-1,3-diyl phosphates. Additionally, Seeberger and coworkers [277,475-482] have recently applied glycosyl phosphates for the synthesis of various oligosaccharides both in solution and in solid-phase syntheses. 

Palmacci, E R, Plante, O J, Seeherger, P H, Oligosaccharide synthesis in solution and on solid support with glycosyl phosphates, Eur. J. Org. Chem., 595-606, 2002. 

Fraser-Reid et al. [21,22] reported the synthesis of polymer supported oligosaccharides using n-pentenyl glycosides, while Seeberger et al. [23] accomplished the synAesis of p-(l- 4)- and p.(2 6)-linked ohgosaccharides using glycosyl phosphates combined with an octenediol linker. 

Oligosaccharide synthesis with tri-chloroacetimidates] general aspects, 290 glycopeptide, 306 glycosyl phosphates, 294, 307, 308 hexasaccharide, 299 inverse procedure, 294 kinetic, thermodynamic effects, 293 Lewis acid catalysis, 289 neighboring group participation,... 

Glycosyl phosphates, building blocks in automated solid-phase synthesis of complex oligosaccharides, were prepared via a 1,2-epoxide (O Scheme 13). Oxidation of the appropriately substituted D-glucal 28 with DMDO followed by reaction with dialkyl phosphate provided the -phosphate 33, which anomerized further to the a-analog [31]. 

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