Concise Click/ESA-CF Synthesis of Periodically-Positioned Trifunctional kyklo-Telechelic Poly(THF)s

Abstract

A concise two-step click/ESA-CF process has been developed to prepare a kyklo-telechelic poly(tetrahydrofuran), poly(THF), having three functional groups at the constant intervals. Thus, a key linear precursor (I), having N-phenylpyrrolidinium salt groups at the chain ends and having two hydroxyl groups at the prescribed inner positions, has been prepared through the alkyne–azide addition (click) reaction using one unit of a linear telechelic poly(THF) having a pair of an alkyne and a hydroxyl groups (1) and two units of a linear asymmetric telechelic poly(THF) having an azide and an N-phenylpyrrolidinium salt group (2). The subsequent polymer cyclization by means of an electrostatic self-assembly and covalent fixation (ESA-CF) process, by employing a dicarboxylate counteranion having an additional alkyne group (3) to I, could produce a trifunctional kyklo-telechelic poly(THF) (II), having two hydroxyl and one alkyne groups positioned at the constant intervals along the ring polymer backbone. The subseque...