7115-19-7Relevant articles and documents
Regio- and stereochemical controlled koenigs-knorr-type monoglycosylation of secondary hydroxy groups in carbohydrates utilizing the high site recognition ability of organotin catalysts
Muramatsu, Wataru,Yoshimatsu, Hirofumi
supporting information, p. 2518 - 2524 (2013/10/21)
The catalytic regio- and stereoselective monoglycosylation of carbohydrates using organotin catalysts is demonstrated. The one-step reaction affords various oligosaccharides linked at the secondary hydroxy group in high chemical yield and good regio- and stereoselectivities. The regioselectivity of the glycosylation is shown to depend on the spatial arrangement of the hydroxy groups in the carbohydrates. Copyright
Intramolecular glycosidation by click reaction mediated spacer generation followed by spacer cleavage
Kumar, Amit,Geng, Yiqun,Schmidt, Richard R.
, p. 6846 - 6851 (2013/03/13)
2-O-Propargyl-substituted glycosyl donors and O-(2-azidobenzyl)-substituted acceptors having a vicinal hydroxy group readily underwent the click reaction. Intramolecular glycosidation with N-iodosuccinimide/trifluoromethansulfonic acid as the activating system afforded β-(1-3)- and α-(1-2)-linked disaccharides as part of 14-membered macrocycles. Descriptors for these reactions are proposed that consider the donor and acceptor attachment sites and the stereochemistry of the functional groups. Investigation of the influence of 2-O-linked 1-aryl-1,2,3-triazol-4-ylmethyl groups, as contained in the spacer, on the anomeric selectivity exhibited no anchimeric assistance. In addition, it was shown that the spacer group can be readily cleaved under Birch reduction conditions. The 1,2,3-triazole-forming click reaction was employed to generate glycosyl donor-spacer-acceptor constructs. Upon glycosidation, 14-membered macrocycles were obtained with high anomeric selectivity. Spacer cleavage was performed under Birch reduction conditions. Copyright
Thermus thermophilus glycosynthases for the efficient synthesis of galactosyl and glucosyl β-(1→3)-glycosides
Drone, Jullien,Feng, Hui-Yong,Tellier, Charles,Hoffmann, Lionel,Tran, Vinh,Rabiller, Claude,Dion, Michel
, p. 1977 - 1983 (2007/10/03)
Inverting mutant glycosynthases were designed according to the Withers strategy, starting from wild-type Thermus thermophilus retaining Tt-β-Gly glycosidase. Directed mutagenesis of catalytic nucleophile glutamate 338 by alanine, serine, and glycine afforded the E338A, E338S, and E338G mutant enzymes, respectively. As was to be expected, the mutants were unable to catalyze the hydrolysis of the transglycosidation products. In agreement with previous results, the E338S and E338G catalysts were much more efficient than E338A. Moreover, our results showed that these enzymes were inactive in the hydrolysis of the α-D-glycopyranosyl fluorides used as donors, and so suitable experimental conditions, under which the rate of spontaneous hydrolysis of the donor was considerably lower than that of enzymatic transglycosidation, provided galactosyl and glucosyl β-(1→3)-glycosides in yields of up to 90%. The structure of native Tt-β-Gly available in the Protein Data Bank offers a good basis for interpretation of our results by means of molecular modeling. Thus, in the case of the E338S mutant, a lower energy of the system was obtained when the donor and the acceptor were in the right position to form the β-(1→3)-glycosidic bond. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
