Synthesis of Glycosides Containing d-Allose

Abstract

Glycosides containing d-allose have been synthesized. Suitable glycosyl donors and promoters or additives are dependent on the nature of the aglycone. For (+)-catechin, using glycosyl fluorides as the glycosyl donor and BF₃ · OEt₂ as the promoter was the optimal choice. On the other hand, glycosyl bromide and tetrabutylammonium bromide (TBAB) or benzyltrietylammonium chloride (TEBAC) as the glycosyl donor and additive, respectively, proved to be the best combination for synthesizing glycosides containing l-ascorbic acid via Lemieux's halide ion-catalyzed glycosidation reaction.