Organocatalyzed Anionic Ring-Opening Polymerizations of N-Sulfonyl Aziridines with Organic Superbases

The anionic ring-opening polymerizations (AROPs) of N-sulfonyl aziridines, in the presence of organic superbases including phosphazene (t-Bu-P4), Verkade’s base (P(i-PrNCH2CH2)3N, TiPP), DBU, MTBD, and N,N,N′,N′-tetramethylguanidine (TMG), using N-benzyl-p-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, t-Bu-P4 and TiPP gave a living/controlled AROP of 2-methyl-N-tosylaziridine (TsMAz), where t-Bu-P4 performed better, affording the metal-free and well-defined poly(sulfonylaziridine)s with high molar masses (Mn(SEC) u003e 30 kg mol–1) and low dispersities (Đ 95%, 5 h). The organocatalyzed AROP allowed the use of lower catalyst (t-Bu-P4) l...