Kinetically Guided On-Demand mCPBA Generation Enables Safe and Sustainable Light-Driven Synthesis of Davis Reagents

Abstract

Oxaziridines, particularly Davis reagents, are widely used oxidants and valuable synthetic intermediates, yet their preparation typically requires handling bulk preformed oxidants such as meta-chloroperbenzoic acid (mCPBA), often in combination with halogenated solvents, creating safety and sustainability concerns. Herein, we report a safe, light-driven sequential strategy that generates mCPBA on demand from meta-chlorobenzaldehyde and molecular O₂ under natural sunlight or LED irradiation and immediately uses it to oxidize N-sulfonyl imines to Davis reagents. Kinetic analysis confirms in situ mCPBA formation without detectable accumulation, minimizing peracid-handling risk. The reaction proceeds at ambient temperature in non-halogenated solvents, offering a practical alternative to conventional protocols. A broad range of N-sulfonyl imines is converted in high yields, and the process is readily scalable. This operationally simple approach combines safety, efficiency, and green-chemistry principles for rapid access to Davis reagents.