Facile construction of 1,2-cis glucosidic linkage using sequential oxidation–reduction route for synthesis of an ER processing α-glucosidase I substrate

• Published in: Tetrahedron letters 2012-08, Vol.53 (33), p.4452-4456
• Main Authors: Iino, Kenta, Iwamoto, Shogo, Kasahara, Yuta, Matsuda, Kana, Tonozuka, Takashi, Nishikawa, Atsushi, Ito, Yukishige, Matsuo, Ichiro
• Format: Article
• Language: English
• Subjects: 1,2-cis Glucoside; Fluorescence-labeled probe; Inversion reaction; Processing α-glucosidase I
• ISSN: 0040-4039; 1873-3581
• DOI: 10.1016/j.tetlet.2012.06.061

The fluorescence-labeled hexasaccharide (Glcα1-2Glcα1-3Glcα1-3Manα1-2Manα1-2Manα) was synthesized as a substrate for the processing enzyme α-glucosidase I. To construct the 1,2-cis glucosidic linkages, we employed an α stereoselective coupling using the mannosyl donor by assisted neighboring-group participation, followed by conversion of the stereochemistry of the C-2 hydroxyl group in the mannose residue using sequential oxidation of C-2 hydroxyl group to a 2-keto group and stereoselective reduction of the hydroxyl group to the gluco-configuration to provide the corresponding α-glucoside derivative. Using this strategy, the three consecutive α-glucosidic linkages were easily obtained in a stereoselective manner. Finally, the Dansyl labeled hexasaccharide derivative was used to measure the activity of processing α-glucosidase I.