Solvent-Free Mechanochemical Synthesis of Aryl Glycosides[1]
摘要:
Aryl glycosides have been prepared from a range of readily available glycosyl halides by a solvent-free mechanochemical procedure employing a planetary ball mill in excellent yields. Besides being a solvent-free reaction, the procedure has been successful in eliminating the need for employing any phase-transfer catalyst in the reaction.
Phenol derived O-glycosides were synthesized using a direct and convenient O-glycosidation, starting from acetylated sugars in the presence of FeCl3, an inexpensive, mild and benign Lewis acid catalyst. The reactions were carried out under both conventional and ultrasonic irradiation conditions. In general, improvement in rates and yields were observed when reactions were carried out under sonication compared with conventional conditions leading to the corresponding beta-O-glycosides as the major anomer. Post-synthetic transformations of iodophenol intermediates led to new resveratrol O-glycoside analogs in good overall yields. (C) 2014 Elsevier B.V. All rights reserved.