A Base-Promoted Tandem Cycloaddition/Air Oxidation Reaction of Electron-Deficient Conjugated Enynes and Hydrazines: Synthesis of Highly Substituted Pyrazoles

Rapid access: A base‐mediated cycloaddition/oxidation reaction of hydrazines and electron‐deficient 1,3‐conjugated enynes gives pyrazole derivatives, some of which are not easily accessible by other methods (see scheme). The reaction conditions are mild, thus enabling a variety of functional groups to be tolerated.