Tailored synthesis of branched polymers with poly(tetrahydrofuran) having an azetidinium salt end group

Monofunctional poly(tetrahydrofuran), (poly(THF)), having a 1-(diphenylmeth yl)azetidinium end group (1) was prepared and subjected to an ion-coupling reaction with various mono- and plurifunctional carboxylates (2a-j). Multia rmed polymers having 2, 3, 4 and 6 arms were obtained in almost pure form b y repeating a simple precipitation of a THF solution of 1 into an ice-coole d aqueous solution containing an excess amount of the relevant plurifunctio nal carboxylates (2c-g) as sodium salts. Another model-branched polymacromo nomer was obtained in high yield through the macromolecular ion-coupling re action of 1 with poly(sodium acrylate) (2h) of DP = 22. Moreover, the ion-c oupling reaction of 1 with sodium (L)-tartarate (2i) or sodium 2,2'-dihydro xy-1,1'-binaphthyl-3,3'-dicarboxylate (2j) allowed one to introduce two hyd roxyl groups at the center of a linear poly(THF) segment.