Successive Synthesis of Well‐Defined Star‐Branched Polymers by “Convergent” Iterative Methodology Using Core‐Functionalized 3‐Arm Star‐Branched Polymer and a Specially Designed 1,1‐Diphenylethylene Derivative

Abstract

AbstractThe synthesis of well‐defined regular and miktoarm star‐branched polymers by a convergent iterative methodology using core‐functionalized 3‐arm star‐branched polymer with 1,1‐diphenylethylene (DPE) moiety and a specially designed DPE derivative is described. The methodology involves the following two reaction steps in the entire iterative synthetic sequence: 1) a coupling reaction of a star‐branched polymer having an anion at the core with a DPE derivative with two benzyl bromide moieties, 1‐{4‐[5,5‐bis(3‐bromomethylphenyl)‐7‐methylnonyl]phenyl}‐1‐phenylethylene, and 2) an addition reaction of the resulting core‐DPE‐functionalized star‐branched polymer with sec‐BuLi to convert the DPE moiety to a DPE‐derived anion. The iterative synthetic sequence including these two reaction steps, 1) and 2), was repeated to successively synthesize star‐branched polymers with more arms. Iteration of this synthetic sequence doubled the number of the arms in the star‐branched polymer. With this methodology, 6‐arm, 12‐arm, and 14‐arm regular star‐branched polystyrenes as well as 6‐arm A2B2C2, A4B2, and 12‐arm A4B4C4 and A8B4 miktoarm star‐branched polymers with well‐defined structures have been successfully synthesized.