A new, iterative strategy of oligosaccharide synthesis based on highly reactive beta-bromoglycosides derived from selenoglycosides

[GRAPHICS] Stereoselective conversion of a selenoglycoside to a ss -bromoglycoside in the absence of a glycosyl acceptor followed by the coupling with another se lenoglycoside affords the corresponding glycosylated selenoglycoside, which could be directly used for the next glycosylation. The iteration of this s equence allows the synthesis of a variety of oligosaccharides including an elicitor active heptasaccharide.