On the mechanism of p-methoxybenzylidene assisted intramolecular aglycon delivery

p-Methoxybenzylidene-assisted intramolecular aglycon delivery was developed in this laboratory and has been demonstrated to be highly efficient and versatile particularly for the synthesis of complex glycoprotein-related glycans. It was revealed that the reaction course of IAD can be clearly monitored by performing the reaction in an NMR tube. Our results suggest that the nonhydrolytic pathway that converts metastable intermediate 3 to the product is functional. Comparative experiments in the presence and absence of water in the reaction media afforded supporting evidence eliminating the possibility of fortuitous contamination of water under standard IAD conditions.