Post‐Synthetic Sulfonation of Metal–Organic Frameworks for Efficient Aziridine Ring‐Opening Functionalization

A sulfonic acid–functionalized metal–organic framework catalyst (MIL‐101‐Fe‐NH‐R‐SO 3 H, R = CH 2 CH 2 CH 2 ) was prepared via post‐synthetic modification through an irreversible ring‐opening reaction with 1,3‐propane sultone. Structural characterization confirmed the successful incorporation of Brønsted acidic sites while preserving the framework integrity. The resulting catalyst efficiently promotes the ring‐opening functionalization of aziridines with a wide range of nucleophiles, including alcohols, amines, water, and azide sources, under mild and solvent‐free conditions, affording diverse 1,2‐difunctionalized products in good to excellent yields. Broad substrate scope, high functional group tolerance, gram‐scale applicability, and good recyclability highlight the practicality of this protocol.