Synthesis of 3-deoxy-2-ulosonic acid KDO and 4-epi-KDN, a highly efficient approach of 3-C homologation by propargylation and oxidation

Through the introduction of a pyruvate segment by asymmetric propargylation and oxidation of terminal alkynes, both KDO and 4-epi-KDN have been concisely synthesized in the furanose form from readily available sugars in high overall yields.