ABSTRACT
Free radical chemistry is a powerful method for forming carbon-carbon bonds. Thus, this methodology would seem to have applications in the generation of C-glycosides. Glucosyl radicals have been found to react preferentially in the a or axial mode to give α-C-glycosides. Giese was one of the first to react glycosyl radicals with suitable acceptors to produce C-glycosides in a highly stereoselective manner. Nicolaou has employed a glycosyl fluoride to synthesize an axial C-glycoside. The reactions exhibit similar selectivity as additions to Michael acceptors and have the advantage that a double bond is left in place on the side chain poised for further manipulation. Keck has assembled C-glycosides using this allylation methodology. The selectivity of C-glycoside formation for the derivative 180 was lower than that of 175 and this is probably due to the effect of the syn carbon bridge on C-2.
