TRANSFORMATION OF THE CATIONIC GROWING CENTER OF POLY(TETRAHYDROFURAN) INTO SAMARIUM AMIDE - BLOCK COPOLYMERIZATION OF TETRAHYDROFURAN WITH METHYL METHACRYLATE

摘要

Two-electron reduction of N-tert-butyl-N-methylaziridinium trifluoromethanesulfonate with samarium(II) iodide in the presence of hexamethylphosphoramide gave the corresponding samarium amides in an excellent yield through the reductive cleavage of a carbon-nitrogen bond of the ring followed by the elimination of ethylene. The produced samarium amide could polymerize methyl methacrylate (MMA) in high initiation efficiency (80%), leading to the formation of highly syndiotactic poly(MMA) (85%) with narrow molecular weight distribution (<1.19). End capping of living poly(THF) with N-tert-butylaziridine and sequential reduction by samarium(II) iodide resulted in the corresponding poly(THF) with samarium amide moiety at the polymer end at functionality of 48%. The polymerization of MMA with the terminal samarium amide produced the block copolymer of THF with MMA. [References: 31]