The synthesis of C-glycosides, sugar analogs in which glycosidic oxygen is substituted by a carbon atom, is of particular interest due to their usefulness as key intermediates for assembling biologically active molecules and natural products. Despite their challenging chemistry, due to their versatility, C-glycosides play a pivotal role in the development of the chemistry of novel materials and bioactive molecules. In this review, we present of various synthetic methodologies, mechanistic proposal and application for 2,3-unsaturated C-glycosides in the last twenty years.