An environmentally friendly process for the preparation of the 4-functionalized N-OR derivatives of 2,2,6,6-tetraalkylpiperidines involves the hydrogen peroxide of the corresponding N-H compound to form the corresponding N-oxyl derivative, reacting two equivalents of the N-oxyl compound with one equivalent of a compound having an allylic hydrogen, a benzylic hydrogen or an activated methine hydrogen to form one equivalent of the corresponding N-OH compound and one equivalent of the corresponding N-OR compound, and recycling the N-OH compound back to the corresponding N-oxyl compound using hydrogen peroxide or air.