Bismuth(III) triflate as a novel and efficient activator for glycosyl halides

Presented herein is the discovery that bismuth(III) trifluoromethanesulfonate (Bi(OTf)3) is an effective catalyst for the activation of glycosyl bromides and glycosyl chlorides. Bi(OTf)3 works well in promoting the glycosidation of differentially protected glucosyl, galactosyl, and mannosyl halides with many classes of glycosyl acceptors. Most reactions complete within 1 h in the presence of only 35% of green and light-stable Bi(OTf)3 catalyst