Regio- and Stereochemical Controlled Koenigs-Knorr-Type Monoglycosylation of Secondary Hydroxy Groups in Carbohydrates Utilizing the High Site Recognition Ability of Organotin Catalysts
作者:Wataru Muramatsu、Hirofumi Yoshimatsu
DOI:10.1002/adsc.201300414
日期:2013.9.16
and stereoselective monoglycosylation of carbohydrates using organotincatalysts is demonstrated. The one‐step reaction affords various oligosaccharides linked at the secondaryhydroxygroup in high chemical yield and good regio‐ and stereoselectivities. The regioselectivity of the glycosylation is shown to depend on the spatial arrangement of the hydroxygroups in the carbohydrates.
acid-catalyzed regioselective Koenigs–Knorr-type glycosylation is presented. The reaction of an unprotected or partially protected glycosyl acceptor with a glycosyl halide donor in the presence of silver oxide and a low catalytic amount of imidazole-containing boronic acid was found to proceed smoothly, which enables construction of a 1,2-trans glycosidic linkage with high regioselectivities. This is the
Regioselective Activation of Glycosyl Acceptors by a Diarylborinic Acid-Derived Catalyst
作者:Christina Gouliaras、Doris Lee、Lina Chan、Mark S. Taylor
DOI:10.1021/ja2062715
日期:2011.9.7
A derivative of diphenylborinic add promotes catalytic, regioselective Koenigs-Knorr glycosylations of carbohydrate derivatives bearing multiple secondary hydroxyl groups. Robust levels of selectivity for the equatorial OH group of cis-1,2-diol motifs are demonstrated in reactions of seven acceptors derived from galactose, mannose, fucose, and arabinose using a variety of glycosyl halide donors. Catalyst control presents a new means of generating defined glycosidic linkages from unprotected or minimally protected carbohydrate feedstocks.