Vessel Effect in C-F Bond Activation Prompts Revised Mechanism and Reveals an Autocatalytic Glycosylation

Activation of C-F bonds under acidic conditions results in the formation of hydrogen fluoride as the reaction progresses. In the following communication, the effect of the vessel material on such reactions has been investigated and a significant difference between an HF-resistant material and common borosilicate glassware has been found. HF was found to react rapidly with borosilicate glassware, seemingly leaching fluorosilicate into solution, but persisted in HF-resistant materials. Several examples of C-F bond activation on glycosyl fluorides and benzyl fluorides as well as NMR-studies suggest a significant effect of the choice of the reaction vessel, leading to the discovery of an autocatalytic glycosylation and a revised mechanism for the activation of benzyl fluorides, suggesting activation by SiF4 rather than HF.