One-Pot Stepwise Approach to β-Enaminoketoestersthrough “Masked” 1,3-Aza-Dipoles.

t-BuOK-mediatedrearrangement of 1,3-ketoesterswith 2-(azidomethyl) aromatics in a two-step, one-pot telescoped sequenceaffords β-enaminoketoesters in moderate to good yields. A novelpathway is proposed in which the umpolung of the azide is achievedfrom electrophilicity to nucleophilicity via deprotonation and undergoesnucleophilic attack onto the 1,3-ketoester. [ABSTRACT FROM AUTHOR]