Towards short PtBAMA segments Table sums up the successful block extension of [PEG-amide-Br]4 adding 6 repeating units tBAMA at each arm without significant changes in Ð if compared to the macroinitiator. This was achieved using ratios of tBAMA:dNbpy:CuCl:macroinitiator = 200:8:4:1 with a concentration of 0.63 mmol/mL for 4 h at 60 °C using a dioxane:DMF ratio of 1:2. Additionally, no deactivator species was added for this reaction, since already enough control over the reaction can be expected due to the use of dNbpy as ligand. As the first reaction starting from [PEG27-amide-Br]4 was sufficient this ratio was transferred to compare experiments starting from the macroinitiators with higher molecular weight. In both cases, the reaction could be successfully transferred to alternative core sizes (Table ). Figure shows the corresponding SEC traces (Figure ) and each in comparison to the respective macroinitiator (Figure ). In summary, all three star-shaped block copolymer species show Ð of 1.06-1.09 being comparable to the respective macroinitiators and show parallel shifts in SEC towards higher molecular weight, hinting towards no or little leftover macroinitiator. Additionally, all the block copolymers were synthesized on a gram scale starting from 800 mg of macroinitiator. We explain the observed shoulder visible at both, macroinitiator and corresponding star-shaped block copolymer due to impurities of the pentaerythritol-core with dipentaerythritol, resulting in additional [PEG-NH2]6 next to [PEG-NH2]4. Attempts to purify the starting material used or the resulting block copolymers resulting were unsuccessful.