Stereoselective Organocatalyzed Glycosylation of Glycosyl Trichloroacetimidate Donors: Thiouracil as Brønsted Acid Catalyst

Abstract

Herein, we report thiouracil‐catalyzed α‐selective O‐glycosylations employing easily accessible glycosyl trichloroacetimidate donors without using any co‐catalyst or additive. A variety of alcohol nucleophiles including saccharides, and amino acids with different protecting groups containing glycosyl trichloroacetimidate donors were successfully α‐glycosylated using an operationally simple protocol. Moreover, mechanistic investigations suggest that thiouracil functions as Brønsted acid/base catalysis in this glycosylation process.