Silver/Segphos‐Catalyzed Asymmetric 1,3‐Dipolar Cycloaddition for the Enantioselective Synthesis of Pyrrolidine Spirooxindoles

Enantioselective synthesis of chiral heterocyclic derivatives is an important and challenging topic in the field of synthetic chemistry. In this work, a silver‐catalyzed asymmetric 1,3‐dipolar cycloaddition of glycine iminoesters with 3‐isopropylidene‐2‐oxindoles was developed. The DTBM‐Segphos‐induced spirooxindole cycloaddition reaction was used to synthesize a range of stereodivergent alkyl‐substituted 3‐methylene‐2‐oxindoles, achieving excellent enantioselectivities (up to 99% ee), good diastereoselectivities (up to 20:1 dr), and high yields under mild reaction conditions. Computational insights from DFT calculations indicate that the Michael addition step is crucial in determining the reaction rate and enantioselectivity.