Cyclization of α, ω heterotelechelic polystyrene prepared by nitroxide-mediated radical polymerization

Polystyrene prepared by nitroxide-mediated radical polymerization (NMRP) bearing a benzyl chloride on the α-terminus was converted to an azide by SN2 displacement, followed by oxidative replacement of the alkoxyamine with a terminal acetylene using ceric ammonium nitrate and propargyl alcohol at the ω-terminus. Macrocyclization using copper(I) catalyzed Huisgen 1,3-dipolar cycloaddition resulted predominately in macrocyclic polymers. Azidation of polystyrene prepared by NMRP upon thermolysis with ethanesulfonyl azide provided partial incorporation of azide in place of the terminal alkoxyamine.