10.1021/acsmacrolett.7b00775.s001 Xin Wang Xin Wang Yaya Liu Yaya Liu Zhenjiang Li Zhenjiang Li Haixin Wang Haixin Wang Hailemariam Gebru Hailemariam Gebru Siming Chen Siming Chen Hui Zhu Hui Zhu Fulan Wei Fulan Wei Kai Guo Kai Guo Organocatalyzed Anionic Ring-Opening Polymerizations of <i>N</i>‑Sulfonyl Aziridines with Organic Superbases American Chemical Society 2017 MTBD loading propagating polymer chains mol tosylaziridine DBU TiPP TMG SEC Bu-P 4 BnN catalyst superbase PrNCH 2 CH 2 AROP 2- methyl metal-free Organocatalyzed Anionic Ring-Opening Polymerizations initiator aziridine 2017-11-14 18:52:08 Journal contribution https://acs.figshare.com/articles/journal_contribution/Organocatalyzed_Anionic_Ring-Opening_Polymerizations_of_i_N_i_Sulfonyl_Aziridines_with_Organic_Superbases/5601364 The anionic ring-opening polymerizations (AROPs) of <i>N</i>-sulfonyl aziridines, in the presence of organic superbases including phosphazene (<i>t</i>-Bu-P<sub>4</sub>), Verkade’s base (P­(<i>i</i>-PrNCH<sub>2</sub>CH<sub>2</sub>)<sub>3</sub>N, TiPP), DBU, MTBD, and <i>N</i>,<i>N</i>,<i>N</i>′,<i>N</i>′-tetramethylguanidine (TMG), using <i>N</i>-benzyl-<i>p</i>-toluenesulfonamide (BnN­(H)­Ts) as initiator were explored to produce metal-free poly­(sulfonylaziridine)­s. Among the superbases used, the catalytic activity was found directly proportional to their basicity. Remarkably, <i>t</i>-Bu-P<sub>4</sub> and TiPP gave a living/controlled AROP of 2-methyl-<i>N</i>-tosylaziridine (TsMAz), where <i>t</i>-Bu-P<sub>4</sub> performed better, affording the metal-free and well-defined poly­(sulfonylaziridine)­s with high molar masses (<i>M</i><sub>n</sub>(SEC) > 30 kg mol<sup>–1</sup>) and low dispersities (<i><i>Đ</i></i> < 1.10) in 3.5 h. For the less reactive monomers of 2-methyl-<i>N</i>-ethylsulfonyl aziridine (EsMAz) and 2-phenyl-<i>N</i>-tosylaziridine (TsPhAz), <i>t</i>-Bu-P<sub>4</sub> showed the same excellent catalytic efficiency (30 equiv, conv. > 95%, 5 h). The organocatalyzed AROP allowed the use of lower catalyst (<i>t</i>-Bu-P<sub>4</sub>) loading than the amount of initiator (BnN­(H)­Ts), but the propagating polymer chains were as many as the number of equivalents of the introduced initiators, which could lower the loading of catalyst used to amounts as low as 0.05 mol %.