Revisiting Glycosylations Using Glycosyl Fluoride by BF3•Et2O: Activation of Disarmed Glycosyl Fluorides with High Catalytic Turnover

Catalytic glycosylations with glycosyl fluorides using BF3 center dot Et2O are presented. Glycosylations with both armed and disarmed donors were efficiently catalyzed by 1 mol% of BF3 center dot Et2O in a nitrogen-filled glovebox without the use of dehydrating agents. Our finding is in sharp contrast with conventional BF3 center dot Et2O-mediated glycosylations, where excess Lewis acid and additives are required. Mechanistic studies indicated that the chemical species formed by the reaction of in situ generated HF and glass vessels are involved in the catalytic cycle.

Automated summary

The study found that catalytic glycosylations using BF3·Et2O could efficiently proceed without the use of dehydrating agents, in contrast to traditional reactions requiring excess Lewis acid and additives. Mechanistic studies showed that chemical species formed by the reaction of in situ generated HF and glass vessels are involved in the catalytic cycle.