AuCl₃-Catalyzed Hemiacetal Activation for the Stereoselective Synthesis of 2-Deoxy Trehalose Derivatives

Abstract

A new practical, catalytic, and highly stereoselective method for directly accessing 1,1-α,α′-linked 2-deoxy trehalose analogues via AuCl 3 -catalyzed dehydrative glycosylation using hemiacetal glycosyl donors and acceptors is described. The method relies on the chemoselective Brønsted acid-type activation of tribenzylated 2-deoxy hemiacetals in the presence of other less reactive hemiacetals.

Switchable reactivity of 2-benzoyl glycals towards stereoselective access of 1-3 and 1-1 S/O linked disaccharides

“…7 Recently, Galan et al described gold catalyzed dehydrative glycosylation using a hemiacetal glycosyl donor to get 1,1-α,α-linked 2-deoxy trehalose derivatives. 8 Glycosylation reactions using sugar-enol-ether-like glycals as a glycosyl donor have been well explored with different glycosyl acceptors for the synthesis of glycosides due to the predictability of new glycosidic linkages. While the external nucleophiles in unsubstituted glycals usually happen from the C-1 position, popularly known as Ferrier glycosylation, the presence of an electron-withdrawing substituent at the C-2 position often switches the reactivity to the C-3 position resulting in C-3 substituted glycosides.…”