Monoamino-terminated and monocarboxylic acid-terminated polystyrenes containing active halogenated end groups were prepared by atom transfer radical polymerization (ATRP) using the so-called initiator method and protective group chemistry. alpha-Chloropropionates were synthesized and utilized as initiators containing the tert-butoxycarbonyl (t-BOC)-protected amino and the tent-butyl (t-Bu)-protected carboxylic acid function, respectively. Optimum polymerization conditions were attained using CuCl/N,N,N',N '',N ''-pentamethyldiethylenetriamine (PMDETA) as catalyst and 10 vol % n-butanol as homogenizing agent at 110 degrees C. However, targeting larger quantities an alternative route was established employing 50 vol % N,N-dimethylformamide (DMF). Subsequent hydrolysis of the omega-tert-butoxycarbonyl polystyrenes afforded well-defined polymers with quantitative deprotection of the functional groups. Comparatively, thermolytic cleavage of the protective sites was studied. H-1 NMR verified the quantitative removal of the t-BOC-protecting groups. Furthermore, the resulting alpha-amino-omega-chloro polystyrenes were reacted with Sanger reagent to confirm the existence of the thereby converted primary amino groups. (C) 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3845-3859, 2009