C-glycoside analogs and methods for their preparation and use

The invention provides versatile sialic acid C-glycoside precursors that are useful for preparing C-glycoside analogs of Gangliosides, peptides, and proteins, as well as synthetic intermediates useful for the preparation of the precursors, and synthetic methods useful for preparing the precursors and the intermediates. The invention also provides gangliosides, peptides, and proteins that comprise sialic acid C-glycoside components, as well as synthetic methods useful for the preparation of such compounds.