Aza-Riley Oxidation of Ugi-Azide and Ugi-3CR Products toward Vicinal Tricarbonyl Amides: Two-Step MCR-Oxidation Methodology Accessing Functionalized α,β-Diketoamides and α,β-Diketotetrazoles

Direct oxidative deamination of glyoxal-derived Ugi-azide and Ugi three-component reaction products readily affords vicinal tricarbonyls (alpha,beta-diketoamides) and alpha,beta-diketotetrazoles with two diversity elements. This significant extension of our previously described multicomponent reaction oxidative deamination methodology is proposed to proceed through a mechanistically distinct SeO2-mediated C-N oxidation derived from an active enol of alpha-amino-beta-ketone systems, effectively an aza-Riley oxidation. This methodology accesses diverse VTC systems from prototypical amines, glyoxaldehydes, and isocyanide building blocks in a mere two steps.