Polymerizations of 2-(Trimethylsilyl)ethanesulfonyl-activated aziridines

A novel N-sulfonyl aziridine, N-((2-(trimethylsilyl)ethyl)sulfonyl)-2-methyl-aziridine (SES-MeAz) was synthesized, and its controlled anionic ring-opening polymerization to form poly(SES-MeAz) studied. The desulfonylation of poly(SES-MeAz)s can be achieved under mild conditions, with tetrabutylammonium fluoride (TBAF) to form polypropylene imine (PPI), although purification of the PPI was not completely successful. The block copolymer p(pTs-MeAz)-b-p(SES-MeAz), (pTs-MeAz = N-para-tosyl-2-methyl-aziridine) was prepared by a sequential polymerization. The desulfonylation of the block copolymer is the first example of the selective removal of a sulfonyl protecting group from a poly(sulfonylazirdine) block copolymer and this is the first formation of a polysufonylaziridine-block-polypropylene imine copolymer. Three-armed star-shaped poly(SESMeAz)s were also successfully synthesized and exhibited improved solubility compared with linear poly(SESMeAz)s.

Automated summary

A novel N-sulfonyl aziridine, N-((2-(trimethylsilyl)ethyl)sulfonyl)-2-methyl-aziridine (SES-MeAz), was synthesized and its controlled anionic ring-opening polymerization was studied. The desulfonylation of poly(SES-MeAz)s to form polypropylene imine (PPI) was achieved under mild conditions using tetrabutylammonium fluoride (TBAF). The first example of the selective removal of a sulfonyl protecting group from a poly(sulfonylazirdine) block copolymer and the first formation of a polysufonylaziridine-block-polypropylene imine copolymer were reported. Successful synthesis of three-armed star-shaped poly(SESMeAz)s with improved solubility compared to linear poly(SESMeAz)s was also demonstrated.