Glycosylation glycosyl fluoride catalyzed

Malet, C., and Planas, A. (1998) From beta-glucanase to beta-glucansynthase glycosyl transfer to alpha-glycosyl fluorides catalyzed by a mutant endoglucanase lacking its catalytic nucleophile. FEBS Lett. 440, 208-212. 

Scheme 13.16 Glycosylation of glycosyl fluoride catalyzed by lanthanide triflate.

Glycosides may also be prepared by enzyme-catalyzed condensation reactions utilizing a glycosyl fluoride. Thus 6-0-a-maltosylcyclodextrins were prepared enzymically from a-maltosyl fluoride (obtained from the corresponding heptaacetate by Zemplen deacetylation) and cyclodex-trins. " ... 

SCHEME 8. Stereoselective /J-glycosylation of various alcohols with a 2-deoxy-2-iodo-olivosyl fluoride catalyzed by Montmorillonite K-10. 

A double mutant (acid/base and nucleophile) Abg E71A E358G was developed58 which efficiently catalyzes thioglycoside formation from a glycosyl fluoridine donor (69) with inverted anomeric stereochemistry. This represents a significant improvement, as glycosyl fluoride donors are much more accessible (Fig. 29). 

Jona, H, Mandai, H, Chavasiri, W, Takeuchi, K, Mukaiyama, T, Protic acid catalyzed stereoselective glycosylation using glycosyl fluorides. Bull. Chem. Soc. Jpn., 75, 291-309, 2002. 

Mukaiyama, T, Jona, H, Takeuchi, K, Trifluoromethanesulfonic acid (TfOH)-catalyzed stereoselective glycosylation using glycosyl fluoride, Chem. Lett., 696-691, 2000. 

Kim, W-S, Hosono, S, Sasai, H, Shibasaki, M, Rare-earth perchlorate catalyzed glycosidation of glycosyl fluorides with trimethylsilyl ethers, Tetrahedron Lett., 36, 4443-4446, 1995. 

Araki, Y, Watanabe, K, Kuan, F H, Itoh, K, Kobayashi, N, Ishido, Y, Synthetic studies by the use of fluorinated intermediates. Part I. A novel procedure for C-glycosylation involving Lewis acid-catalyzed coupling-reactions of glycosyl fluorides with enol trimethylsilyl ethers, Carbohydr. Res., Ill, C5-C9, 1984. 

Within the present article, a few selected examples are provided ofboth classical and more recent glycosylation methods applied to the synthesis of sLcL sLe", or of sulfated Lewis determinants. Recent procedures involve the use of glycal donors as developed by Danishefsky and his associates, of glycosyl fluorides according to Mukaiyama and Nicolaou, of sulfoxide donors as reported by Kahne, and enzyme-catalyzed oligosaccharide syntheses as developed by the schools of Whitesides, Wong, and Paulson. ... 

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