USE OF A PHENYL 1-SELENOGALACTOFURANOSIDE AS A GLYCOSYL DONOR FOR THESYNTHESIS OF GALACTOFURANOSYL-CONTAINING DISACCHARIDES

The use of acetylated phenyl 1-seleno-beta-D-galactofuranoside as a gl ycosyl donor for the synthesis of protected D-Galf-beta-(1 --> 3)-alph a-D-Manp as its methyl or ethylthio glycoside has been demonstrated. A ctivation of the selenoglycoside over a thioglycoside acceptor by NIS/ TfOH is extremely selective and gives the ethylthio disaccharide in 91 % yield. The parent disaccharide is found as a terminal and branched u nit in the lipopeptidophosphoglycan oligosaccharides of the protozoan Trypanosoma cruzi, the causative agent of Chagas' disease. (C) 1998 El sevier Science Ltd.