Synthesis of Fully and Partially Protected Alkyl 1-Thio-β-l-fucopyranosides

Abstract

Fully acetylated (1d) and a mixture of partially acetylated (1a, 1b, 1c) ethyl 1-thio-β-L-fucopyranosides have been prepared in high yields from peracetylated fucopyranosyl chloride (1e) with sodium ethanethiolate/ethanethiol in 1,2-dimethoxyethane. The same compounds were synthesised from peracetylated methyl 1-thio-β-L-fucopyranoside (1g) with bromine and ethanethiolate. Selective hydrolysis of 1g led to the removal of the 3-O-acetyl group, resulting in 1h. Chemospecific and stereospecific α-fucosidation of the partially acetylated thioglycosides 1a, 1b and 1c was achieved using benzyl-protected methyl 1-thio-β-(1i) and α- (1r) L-fucopyranosides and DMTST promoter.

Notes

On leave from Central Research Institute for Chemistry of the Hungarian Academy of Sciences