N‐Heterocyclic Carbene‐Catalyzed All Carbon‐[4+2] Cyclocondensation of α,β‐Unsaturated Acyl Chlorides with 3‐Alkylenyloxindoles

Although the NHC-catalyzed cyclization reactions have been well established for the synthesis of various heterocycles, the corresponding all carbon cyclization reaction for the synthesis of carbocycles is far less established. In this note, the NHC-catalyzed all carbon [4+2] cyclocondensation of α,β-unsaturated acyl chlorides and 3-alkenyloxindoles was developed to give the corresponding spirocarbocyclic oxindoles in good yield with good to high diastereoselectivities.