2-Azaallyl Anion Initiated Ring-Opening Polymerization of N-Sulfonyl Aziridines: One-Pot Synthesis of Primary Amine-Ended Telechelic Polyaziridines

Using the easily accessible 2-azaallyl anions as initiators, the one-pot synthesis of well-defined primary amine-ended telechelic polyaziridines (alpha-NH2 PAzs) has been achieved through the ring-opening polymerization (ROP) of N-sulfonyl aziridines followed by hydrolysis of the diphenylketimine moiety (-N=C-Ph-2). The 2-azaallyl anions were synthesized from the reaction of diphenylketimine or N-[aryl-methylene]-alpha-phenylbenzenemethanamine with potassium bis(trimethylsilyl) amide (KHMDS) in situ and used to initiate the ROP of aziridines leading to well-defined alpha-(Ph2C=N)-alpha'-aryl-omega-NH PAzs. Along with the diphenylketimine group (-N=C-Ph-2), aryl functionalities, such as pyridine and triphenylphosphine moieties, can also be incorporated to the chain end. Chain extension has been applied for the synthesis of poly(N-sulfonyl aziridine)-block-poly(epsilon-caprolactone) (PAz-b-PCL) block copolymers by utilization of the primary amine end group as initiating sites for the ROP of epsilon-caprolactone catalyzed by tin 2-ethyl hexanoate (SnOct(2)). Taking advantage of this synthetic approach, core cross-linked multiarm star (CCS) polymers with an outermost shell having amino and triphenylphosphine functionalities have been synthesized via arm-first strategy.