In this article, we demonstrate the Passerini three‐component reaction as a simple, effective method for the synthesis of polymers with double functional end groups, which are key precursors for the preparation of ABC miktoarm terpolymers. Thus, via the one‐step Passerini reaction of monomethoxy poly(ethylene glycol)–propionaldehyde (PEG‐CHO) with 2‐bromo‐2‐methylpropionic acid and propargyl isocyanoacetamide, the PEG chain end was simultaneously functionalized with one atom transfer radical polymerization (ATRP) initiating site and one alkynyl group. The resulting PEG(‐alkynyl)‐Br was then used for the synthesis of three types of miktoarm ABC terpolymers via two approaches. First, we conducted ATRP of N‐isopropylacrylamide (NIPAM), then click reaction with azido‐terminated polystyrene (PS‐N3) or poly(tert‐butyl acrylate) (PtBA‐N3) and obtained two ABC miktoarm terpolymers PEG(‐b‐PNIPAM)‐b‐PS and PEG(‐b‐PNIPAM)‐b‐PtBA. Alternatively, we conducted single electron transfer living radical polymerization of tBA and click reaction with PS‐N3 simultaneously to give PEG(‐b‐PtBA)‐b‐PS. All the polymer precursors and miktoarm terpolymers have been characterized by 1H NMR, Fourier transform infrared, gel permeation chromatography, demonstrating that both approaches provided well‐defined ABC miktoarm terpolymers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013

A new polymerization method based on the Passerini three‐component reaction of a dicarboxylic acid, an alcohol, and a diisocyanide in the presence of an oxidant is reported. This polymerization involves the concurrent oxidation of alcohols by o‐iodoxybenzoic acid (IBX) and the Passerini three‐component polymerization. The kinetics of the alcohol oxidation and the Passerini reaction are investigated, and the results indicate that the cascade process can occur efficiently. The reaction conditions are optimized, and various functional alcohols are examined to get insight into the applicability of the method. Based on the optimized conditions, a variety of functional poly(ester amide)s are prepared in a one‐pot fashion via using 1,6‐diisocyanohexane, 1,6‐hexanedioic acid, different functional alcohols, and iodoxybenzoic acid. The introduction of functional pendant groups, especially alkynyl, alkenyl and epoxy groups, to the final poly(ester amide)s, provides an efficient way for further modification of the polymers.

Self‐immolative polymers are a special kind of degradable polymers that depolymerize into small molecules through a cascade of reactions upon stimuli‐triggered cleavage of the polymer chain ends. This work reports the design and synthesis of a fluoride‐triggered self‐immolative polyester. A 2,4‐disubstitued 4‐hydroxy butyrate is first confirmed to quickly cyclize in solution to form a γ−butyrolactone derivative. Then, the Passerini three component reaction (P‐3CR) of an AB dimer (A: aldehyde, B: carboxylic acid) with tert‐butyl isocyanide or oligo(ethylene glycol) isocyanide affords two poly(2,4‐disubstitued 4‐hydroxybutyrate) derivatives (P2 and P3). Two silyl ether end‐capped polymers (P4 and P5) are abtained from P2 and P3, and their degradation in solution is examined by NMR spectrum and size exclusion chromatography. Polymers P4 and P5 are stable in the absence of tetrabutylammonium fluoride (TBAF), while in the presence of TBAF, the molar masses of P4 and P5 gradually decrease with time together with the increase of the amount of formed 2,4‐disubstitued γ‐butyrolactone. The depolymerization mechanism is proposed. The first step is the fast removal of the silyl ether by fluoride. Then, the released hydroxyl group initiates the quick head‐to‐tail depolymerization of the polyester via intramolecular cyclization.