End-reactive poly(tetrahydrofuran) for functionalization and graft copolymer synthesis via a conjugate substitution reaction

Abstract

α-(Chloromethyl)acryloyl cation, prepared from the corresponding acyl chloride and silver triflate, was used as an initiator for the living, cationic ring-opening polymerization of tetrahydrofuran. The α-end of the resulting poly(tetrahydrofuran) has an α-(chloromethyl)acrylate skeleton, which is an excellent substrate for nucleophilic conjugate substitution. In fact, treatment with a phenol resulted in a functionalized α-end. Moreover, 2-aminoethylanol and 2-mercaptoethanol afforded doubly functionalized polymers with two hydroxy groups at the α-ends via conjugate substitution and subsequent addition reactions. Since α-(chloromethyl)acrylate can be attacked by two equivalents of a nucleophile, it can function as a monomer in polycondensations with dithiols. Therefore, the α-(chloromethyl)acrylate chain end was subjected to polycondensation with 1,10-decandithiol in the presence of Bu3P, resulting in a graft copolymer. The above results suggest that the α-(chloromethyl)acryloyl cation is a functional initiator for incorporating a chain end reactive to a variety of nucleophiles for single and double end-functionalizations and the preparation of graft copolymers. Conjugate subst. allows single/double end-functionalization and graft copolymer synthesis.