Article révisé par les pairs
Résumé : Functionalized, saturated nitrogen heterocycles form the core structures of many molecules that have an impact on our daily lives, including natural products and pharmaceuticals. An efficient and general method for the direct alpha-peroxidation of saturated nitrogen heterocycles is reported. Upon simple reaction with tert-butyl hydrogen peroxide in the presence of catalytic amounts of copper(II) chloride and 1,10-phenanthroline, a broad range of nitrogen heterocycles equipped with a 2-pyridyl directing group are readily peroxidized at room temperature to the corresponding stable hemiaminals with full regioselectivity. These hemiaminals were, moreover, shown to be remarkably efficient precursors of the corresponding iminium ions upon simple treatment with citric acid, enabling, overall, the introduction of a series of nucleophiles at the alpha position of the starting nitrogen heterocycles.