Folding Construction of a Pentacyclic Quadruply fused Polymer Topology with Tailored kyklo‐Telechelic Precursors

Abstract

A pentacyclic quadruply fused polymer topology has been constructed for the first time through alkyne-azide addition (click) and olefin metathesis (clip) reactions in conjunction with an electrostatic self-assembly and covalent fixation (ESA-CF) process. Thus, a spiro-type, tandem tetracyclic poly(tetrahydrofuran), poly(THF), precursor having two allyloxy groups at the opposite positions of the four ring units was prepared by the click-linking of one unit of an eight-shaped precursor having alkyne groups at the opposite positions with two units of a single-cyclic counterpart having an azide and an alkene group at the opposite positions. Both are obtainable through ESA-CF. The subsequent metathesis clip-folding of the tetracyclic precursor could afford a pentacyclic quadruply fused polymer product, of "shippo" form, in 19% yield.

Cyclic polymers revealing topology effects upon self-assemblies, dynamics and responses

“…39 Also in the future, a variety of topology effects of not only simple ring polymers but also of multicyclic polymers 40,41 are anticipated to be disclosed, and to be applied in practice for the routine methodology of polymer materials designs. Thereby a variety of single-and multicyclic polymers having programmed chemical structures with guaranteed qualities have now become obtainable.…”

Hyperbranched Multicyclic Polymer Built from Tailored Multifunctional Monocyclic Prepolymer

“…The combination of atom transfer radical poly merization (ATRP) and coppercatalyzed azidealkyne cycloaddition (CuAAC) is a powerful tool in the ringclosure strategy, because the azide group is relatively easy to obtain by substitution reaction of the ter minal halogen atom of polymer obtained via ATRP, which can be used in further click reaction, and considerable successful constructions have been achieved in recent years by this means. [5,[14][15][16][17][18] Reversible addi tionfragmentation chain transfer (RAFT) polymerization also plays an important role in the synthesis of cyclic polymers. [19][20][21][22] A significant advantage of RAFT polymerization over other living radical polymerization (LRP) processes is that it is compatible with a very broad set of monomers, even functional monomers with different groups including acid, amino, and salt.…”

“…In unimolecular ring closure process, linear polymers couple intramolecularly to afford cyclic polymers, thus it is not limited by stoichiometric equivalent. The combination of atom transfer radical polymerization (ATRP) and copper‐catalyzed azide‐alkyne cycloaddition (CuAAC) is a powerful tool in the ring‐closure strategy, because the azide group is relatively easy to obtain by substitution reaction of the terminal halogen atom of polymer obtained via ATRP, which can be used in further click reaction, and considerable successful constructions have been achieved in recent years by this means . Reversible addition‐fragmentation chain transfer (RAFT) polymerization also plays an important role in the synthesis of cyclic polymers .…”

Topological Polymer Chemistry: A Personal Reflection Upon the Evolution and Prospects of Synthetic Macromolecular Chemistry

“…The three forms of dicyclic constructions, i. e., θ ( fused ), 8 ( spiro ) and manacle ( bridged ), as well as a trefoil ( spiro tricyclic) construction have been effectively produced through the ESA‐CF process . In addition, the ESA‐CF protocol has been extended in conjunction with the effective covalent linking chemistries, in particular an alkyne‐azide cross‐coupling , i. e., click , reaction and a metathesis homo‐coupling , i. e., clip , reaction . Thus, a series of single cyclic and multicyclic polymer precursors ( kyklo ‐telechelics) as large as 300‐membered atomic rings have been prepared by the ESA‐CF process for the subsequent click and/or clip construction of complex multicyclic polymer topologies .…”

“…[16] In addition, the ESA-CF protocol has been extended in conjunction with the effective covalent linking chemistries, in particular an alkyne-azide crosscoupling, i. e., click, reaction and a metathesis homo-coupling, i. e., clip, reaction. [15,[17][18][19] Thus, a series of single cyclic and multicyclic polymer precursors (kyklo-telechelics) as large as 300-membered atomic rings have been prepared by the ESA-CF process for the subsequent click and/or clip construction of complex multicyclic polymer topologies. [15,20,21] These topologically complex but precision polymers are considered as important model polymers for the experimental investigation of any topology effects on their basic polymer properties, along with computational modelling/simulation studies.…”