Access to 6-Deoxy-heptose Constructs by One Carbon Homologation of Hexoses with Malononitrile: Divergent Synthesis of Campylobacter jejuniStrain 81-176 Capsular Trisaccharide Repeating Unit Derivatives

An efficient approach to 6-deoxy-heptose constructs has been established by one-carbon homologation of the sugar chain of hexoses. The reaction features the formation of sugar-based α-substituted propanedinitriles and ensuing diverse oxidative transformations under mild reaction conditions that are compatible with a wide range of sugars bearing various functional/protecting groups. The applications of this method are demonstrated by a divergent assembly of Campylobacter jejunistrain 81-176 capsular trisaccharide repeating unit derivatives.