Convenient Multigram Scale Glycosylations of Scented Alcohols Employing Phase‐Transfer Reactions

Abstract

Various conditions for glycosylation (Koenigs–Knorr, Helferich, trichloroacetimidate, Fischer–Raske, phase‐transfer methods) of 3‐ethoxy‐4‐hydroxybenzaldehyde (ethyl vanillin), 3‐hydroxy‐2‐methyl‐4‐pyranone (maltol) and 2,5‐dimethyl‐4‐hydroxy‐3(2H)‐furanone (furaneol®) were evaluated, taking into account yields and ease of preparation (e.g., utilized donor, catalyst, conditions). The best results were achieved employing phase transfer catalysis in a two‐phase solvent mixture. To increase water solubility for better applicability, the hitherto unknown maltosides of the corresponding alcohols were synthesized, again proving the value of phase‐transfer conditions for glycosylation of phenols.