In this study, we developed a route for the tris(mono-ferrocene-functionalised β-diketonato) manganese(III)-complex catalysed diastereoselective oxygenative aminoperoxidation of unactivated alkenes using molecular oxygen in air. In the reaction, ethanol is used as a solvent, and it proceeds at room temperature under open air. Due to its wide range of substrate scope, functional tolerance, simple operation and mild and environmentally friendly conditions, the reaction is a promising synthetic approach for synthesising valuable isoxazolidine rings as not only privileged structures in natural products but also versatile synthons for 1,3-amino alcohols.