Regioselective, tin-free sulfation of a number of unprotected glycopyranosidesderived from L-fucose, L-rhamnose, D-arabinose, D-glucose, D-galactose, and D-trehalose was achieved by using phenylboronic acid for masking the hydroxy groups and a 2,2,2-trichloroethyl-protected sulfurylimidazolium salt as the sulfating reagent. The formation of phenylborate ester remarkably improved the solubility of
Temporary Protection and Activation in the Regioselective Synthesis of Saccharide Sulfates
作者:Steven Langston、Bruno Bernet、Andrea Vasella
DOI:10.1002/hlca.19940770821
日期:1994.12.14
Regioselectivesulfation with Et3N · SO3 of partially protected or unprotected glycosides via stannanediyl acetals or stannyl ethers, combined with persistent or temporary protecting groups is described. Stannylation of phenylboronates, followed by sulfation and aqueous workup, is an efficient way for the synthesis of monosulfated monosaccharides. The stannanediyl acetal 2 led in high yields to 3a