[en] PROBLEM TO BE SOLVED: To provide a method for producing a functionalized alkoxyamine initiator and its use in radical polymerization process. ; SOLUTION: The invention provides a one-pot process for the production of a functionalized alkoxyamine of general formula (I) (for example, R<SP>1</SP>and R<SP>2</SP>are each H; R<SP>3</SP>is phenyl; and R<SP>4</SP>and R<SP>5</SP>together with nitrogen atom form an alicyclic 6-membered ring). The method includes (1) the formation of an aqueous phase and nitroxyl radical by reacting an oxidizing agent with a secondary amine having steric hindrance and (2) the removal of the aqueous phase and the addition of one or more vinyl monomers to the nitroxyl radical according to the method and system for the production of the radical. The invention further provides a monomer polymerization method using the functionalized alkoxyamine.