Solvent- or Base-Controlled Diastereoselectivity and Chemoselectivity for the Reaction of Ketenimine Zwitterionic Salts

Ketenimine zwitterionic salt (KZS), a novel and stable ketenimine precursor, is still underexplored in the realm of chemical synthesis. In this study, we demonstrate the transformation of pyrrole derivatives through the cyclization of KZS with α-aminoketones. The diastereoselectivity of this reaction is influenced by the solvent, enabling the isolation of 3-hydroxypyrrolidine diastereomers with the highest reported dr value of 21 : 1. Furthermore, the chemoselectivity is modulated by the choice of base, yielding 2-aminopyrrole derivatives as the major products. This research offers a sustainable approach to harnessing the potential of KZS in organic synthesis, contributing to a greener chemical process.