The New Observation of Intramolecular Acyl Transfer from Aglycon to Sugar of C-Glycoside. The Regioselective and Single Step Acylation of 2′-Hydroxyl Group of Free C-Glucopyranoside.

Abstract A new intramolecular acyl transfer from aglycon to sugar moiety in C -glucopyranoside has been observed. This unusual acyl transfer reaction has been extended to the regioselective and direct acylations of 2′-hydroxyl group of free C -glucopyranoside and one step syntheses of four natural C -glycosylchromones from aloesin glucopyranoside have also been achieved by this method. © 1997 Elsevier Science Ltd.