Modular and stereoselective synthesis of Si-/Ge-glycosides via palladium-catalyzed bis-silylation and bis-germanylation of glycals

Abstract

In this study, we report an efficient palladium-catalyzed C–H silylation and germanylation that enables rapid modular and stereoselective access to various highly decorated Si- and Ge-glycosides. The protocol employs hexamethyldisilane and hexamethyldigermane as the model bis-silylation and bis-germanylation reagents, respectively, with NBE derivatives as the ortho-C–H activator. Additionally, a series of Si-glycosides bearing one (Z)-β-substituted vinylsilane and Ge-glycosides bearing one (Z)-β-substituted vinylgermane were also obtained under mild conditions by employing 2,3-dicarbomethoxy-7-oxanorbornadiene (ONBD) as both a switch and an ethylene surrogate. This work pioneers the Catellani strategy in the assembly of Si- and Ge-glycosides, establishing an efficient platform for bioactive glycomimetic development and advancing carbohydrate-based drug discovery.