Switchable synthesis of benzimidazole/quinoxaline C-glycosides with o-phenylenediamines and sulfoxonium ylide glyco-reagents

A novel switchable approach for the synthesis of benzimidazole/quinoxaline C-glycosides is introduced. This versatile catalytic system facilitates the reaction of o-phenylenediamines with carbonyl sulfoxonium ylide glyco-reagents under mild conditions to selectively form 2-glycoside quinoxalines and 2-glycoside benzimidazoles, through [OsCl₂(p-cymene)]₂ and AgSbF₆ catalysts, respectively. The process is adaptable as it can generate a variety of heteroarene C-glycosides by accommodating a wide range of sugar donors. It is also ideal for the modification of compounds like varenicline due to its excellent functional group compatibility, mild reaction conditions, and wide substrate range.