Lewis‐Base‐Catalyzed Annulations of Nitroallylic Acetates as C3 Synthons with Electron‐Deficient Alkenes

Abstract 2‐Nitroallylic acetates have been demonstrated to be versatile C3 synthons in Lewis‐base‐catalyzed annulation reactions. Catalyzed by PhPMe2 (20 mol %), they readily undergo a cascade [3+2] annulation/allylic alkylation reaction with electron‐deficient alkenes to provide cyclopentenes and even spirocyclopenteneoxindoles in moderate to good yields and high diastereoselectivity. Under the catalysis of 4‐dimethylaminopyridine (20 mol %), 2‐nitroallylic acetates also undergo a [3+3] annulation reaction with 1,1‐dicyanoalkenes to give cyclohexenes. This work further broadens the scope of the Lewis‐base‐catalyzed annulation protocol for modified allylic derivatives.