Divergent Chemo-, Regio-, and Diastereoselective Normal Electron-Demand Povarov-Type Reactions with alpha-Oxo-ketene Dienophiles

International audienceThe reactions between electron-rich 2-aza- dienes and α-oxo-ketenes derived from the Wolff rearrange- ment of 2-diazocycloalkane-1,3-diones chemo- and regiose- lectively produced spiro hydropyrid-4-ones with good to excellent diastereoselectivities. These reactions are likely to proceed via a domino Wolff/Friedel−Crafts/intramolecular Mannich process. Prolonged domino sequences also allowed the expeditious preparation of a series of pyrazolopyridine and pyridopyrimidine heterocycles