Mild oxygen activation with isobutyraldehyde promoted by simple salts

Oxygen activation using an aldehyde as a sacrificial reductant and mediated by metalloporphyrins is a radical process with a variable induction period in which the macrocycle function is to generate the acyl radicals to initiate a chain mechanism. This function can be also efficiently promoted by simple metal salts, which leads to a very simple and practical oxidative system that is able to epoxidize alkenes in good yields.