A new reagent system consisting of a Lewis acid such as BF3·Et2O or Cu(OTf)2, the
mild protic acid hexafluoroisopropanol and the reducing quenching agent triethylsilane
was elaborated for O-, N- and S-detritylation of nucleoside, carbohydrate and amino
acid derivatives. The method is compatible with acetyl, silyl, acetal and Fmoc groups.