Per-O-Trimethylsilyl-α-L-Fucopyranosyl Iodide: A Novel Glycosylating Agent for Terminal α-L-Fucosylation

Trimethylsilylation of L-Fucose, followed by reaction with TMS-I, yields in situ the per-O-trimethylsilyl-α-L-fucopyranosyl iodide (2) without chromatography. Compound 2, in the absence of a promoter, reacts with alcohols to give α-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 temporary protecting groups in oligosaccharide synthesis involving terminal fucosylation.