Diastereodivergent Synthesis of Fully Disubstituted Spiro[indoline-3,2'-pyrrolidin]-2-ones via Tuneable Lewis base/Brønsted base-promoted (3+2) Cycloadditions

Herein we report a diastereodivergent synthesis of fully disubstituted spiro[indoline-3,2'-pyrrolidin]-2-ones through base-promoted (3+2) cycloadditions. Importantly, The catalysts were found to full control over the configuration of the stereocenters. When Lewis base was used as catalyst, good to excellent yields and diastereoselectivities were obtained, regardless of the properties of the substituents. While spiro[indoline-3,2'-pyrrolidin]-2-ones of a different diastereoisomer were produced with good to excellent yields by applying a Bronsted base. ESI-MS experiment prove the existence of key zwitterionic intermediates.