PER-O-TRIMETHYLSILYL-ALPHA-1-FUCOPYRANOSYL IODIDE - A NOVEL GLYCOSYLATING AGENT FOR TERMINAL ALPHA-L-FUCOSYLATION

Trimethylsilylation of L-Fucose, followed by reaction with TMS-I, yiel ds in situ the per-O-trimethylsilyl-alpha-L-fucopyranosyl iodide (2) w ithout chromatography. Compound 2, in the absence of a promoter, react s with alcohols to give alpha-L-fucopyranosides in good yields (45-90% ). The net result is that hydrogenation is not an essential final step in the synthesis of fucosides and that benzyl groups may be used as t emporary protecting groups in oligosaccharide synthesis involving term inal fucosylation.