Synthesis of tadpole polymers via triple click reactions: Copper‐catalyzed azide–alkyne cycloaddition,diels–alder,and nitroxide radical coupling reactions

We designed a trifunctional initiator ( 3 ) containing anthracene, bromide, and OH functionalities and subsequently used as an initiator in atom transfer radical Polymerization (ATRP) of styrene to yield linear polystyrene (PS) with α‐anthracene, OH, and ω‐bromide terminal groups, of which bromide is later transformed into azide to result in the linear anthracene‐, OH‐, and azide‐terminated PS (l‐α‐anthracene‐OH‐ω‐azide‐PS). The copper‐catalyzed azide–alkyne cycloaddition reaction between l‐α‐anthracene‐OH‐ω‐azide‐PS and α‐furan‐protected‐maleimide‐ω‐alkyne linkage, 4 afforded the linear anthracene‐, OH‐, and maleimide‐terminated PS. The cyclization via intramolecular Diels–Alder click reaction of this linear PS and the subsequent conversion of the hydroxyl into bromide resulted in the cyclic PS with one bromide located on the ring, (c‐PS)‐Br. Finally, the c‐PS‐Br was clicked with either well‐defined tetramethylpiperidine‐1‐oxyl‐terminated poly(ethylene glycol) (PEG) or poly(ε‐caprolactone) (PCL) yielding the tadpole polymer, (c‐PS)‐b‐PEG or (c‐PS)‐b‐PCL. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

3‐miktoarm star terpolymers using triple click reactions: Diels–Alder,copper‐catalyzed azide‐alkyne cycloaddition,and nitroxide radical coupling reactions

Well‐defined linear furan‐protected maleimide‐terminated poly(ethylene glycol) (PEG‐MI), tetramethylpiperidine‐1‐oxyl‐terminated poly(ε‐caprolactone) (PCL‐TEMPO), and azide‐terminated polystyrene (PS‐N₃) or ‐poly(N‐butyl oxanorbornene imide) (PONB‐N₃) were ligated to an orthogonally functionalized core ( 1 ) in a two‐step reaction mode through triple click reactions. In a first step, Diels–Alder click reaction of PEG‐MI with 1 was performed in toluene at 110 °C for 24 h to afford α‐alkyne‐α‐bromide‐terminated PEG (PEG‐alkyne/Br). As a second step, this precursor was subsequently ligated with the PCL‐TEMPO and PS‐N₃ or PONB‐N₃ in N,N‐dimethylformamide at room temperature for 12 h catalyzed by Cu(0)/Cu(I) through copper‐catalyzed azide‐alkyne cycloaddition and nitroxide radical coupling click reactions, yield resulting ABC miktoarm star polymers in a one‐pot mode. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Heterograft brush copolymers via romp and triple click reaction strategies involving CuAAC,diels–alder,and nitroxide radical coupling reactions

In this study, an equimolar mixture of oxanorbornenyl‐anthracene (ONB‐anthracene), oxanorbornenyl‐bromide (ONB‐Br), and oxanorbornenyl tosylate (ONB‐OTs) was polymerized via ring opening metathesis polymerization using the first generation Grubbs' catalyst in CH₂Cl₂ at room temperature to form poly(ONB‐anthracene‐co‐ONB‐Br‐co‐ONB‐OTs)₁₀ copolymer as a main backbone. Next, this main backbone was sequentially clicked with a furan protected maleimide‐terminated poly(methyl methacrylate), 2,2,6,6‐tetramethyl‐1‐piperidinyloxy‐terminated poly(ethylene glycol), and alkyne‐terminated poly(ε‐caprolactone) (PCL₂₀‐alkyne) via Diels–Alder, nitroxide radical coupling, and copper‐catalyzed azide‐alkyne cycloaddition, respectively, to yield a poly(ONB‐g‐PMMA‐co‐ONB‐g‐PEG‐co‐ONB‐g‐PCL)₁₀ heterograft brush copolymer © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Linear tetrablock quaterpolymers via triple click reactions,azide‐alkyne,diels–alder,and nitroxide radical coupling in a one‐pot fashion

Azide‐alkyne and Diels–Alder click reactions together with a click‐like nitroxide radical coupling reaction were used in a one‐pot fashion to generate tetrablock quaterpolymer. The various living polymerization generated linear polymers with orthogonal end‐functionalities, maleimide‐terminated poly(ethylene glycol) (PEG‐MI), anthracene‐ and azide‐terminated polystyrene, alkyne‐ and bromide‐terminated poly(tert‐butyl acrylate) or alkyne‐poly(n‐butyl acrylate), and tetramethylpiperidine‐1‐oxyl (TEMPO)‐terminated poly(ε‐caprolactone) (PCL‐TEMPO) were clicked together in a one‐pot fashion to generate PEG‐b‐PS‐b‐PtBA‐b‐PCL or PEG‐b‐PS‐b‐PnBA‐b‐PCL quaterpolymer using Cu(0), CuBr, and N,N,N′,N″,N″‐pentamethyldiethylenetriamine as catalyst in dimethyl formamide at 80 °C for 36 h. Linear precursors and target quaterpolymers were analyzed via ¹H NMR and gel permeation chromatography. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Star polymers by photoinduced copper‐catalyzed azide–alkyne cycloaddition click chemistry

Well‐defined star polymers consisting of tri‐, tetra‐, or octa‐arms have been prepared via coupling‐onto strategy using photoinduced copper(I)‐catalyzed 1,3‐dipolar cycloaddition click reaction. An azide end‐functionalized polystyrene and poly(methyl methacrylate), and an alkyne end‐functionalized poly(ε‐caprolactone) as the integrating arms of the star polymers are prepared by the combination of controlled polymerization and nucleophilic substitution reactions; whereas, multifunctional cores containing either azide or alkyne functionalities were synthesized in quantitatively via etherification and ring‐opening reactions. By using photoinduced copper‐catalyzed azide–alkyne cycloaddition (CuAAC) click reaction, reactive linear polymers are simply attached onto multifunctional cores to form corresponding star polymers via coupling‐onto methodology. The chromatographic, spectroscopic, and thermal analyses have clearly demonstrated that successful star formations can be obtained via photoinduced CuAAC click reaction. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1687–1695     

Quadruple click reactions for the synthesis of cysteine‐terminated linear multiblock copolymers

Synthesis of cysteine‐terminated linear polystyrene (PS)‐b‐poly(ε‐caprolactone) (PCL)‐b‐poly(methyl methacrylate) (PMMA)/or poly(tert‐butyl acrylate)(PtBA)‐b‐poly(ethylene glycol) (PEG) copolymers was carried out using sequential quadruple click reactions including thiol‐ene, copper‐catalyzed azide–alkyne cycloaddition (CuAAC), Diels–Alder, and nitroxide radical coupling (NRC) reactions. N‐acetyl‐L ‐cysteine methyl ester was first clicked with α‐allyl‐ω‐azide‐terminated PS via thiol‐ene reaction to create α‐cysteine‐ω‐azide‐terminated PS. Subsequent CuAAC reaction with PCL, followed by the introduction of the PMMA/or PtBA and PEG blocks via Diels–Alder and NRC, respectively, yielded final cysteine‐terminated multiblock copolymers. By ¹H NMR spectroscopy, the DP_ns of the blocks in the final multiblock copolymers were found to be close to those of the related polymer precursors, indicating that highly efficient click reactions occurred for polymer–polymer coupling. Successful quadruple click reactions were also confirmed by gel permeation chromatography. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Various polycarbonate graft copolymers via diels–alder click reaction

In this work, we used Diels–Alder click reaction for the preparation of various types of aliphatic polycarbonates (PCs). We first prepared a novel anthracene‐functionalized cyclic carbonate monomer, anthracen‐9‐ylmethyl 5‐methyl‐2‐oxo‐1,3‐dioxane‐5‐carboxylate (2), followed by ring‐opening polymerization of this monomer to prepare PC with pendant anthracene groups (PC‐anthracene) using 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU)/1‐(3,5‐bis(trifloromethyl)phenyl)‐3‐cyclohexylthiourea (TU) as the catalyst and benzyl alcohol as the initiator in CH₂Cl₂ at room temperature. Subsequently, the resulting PC‐anthracene (M_n,TDGPC = 6000 g/mol, M_w/M_n = 1.22) was grafted with a linear α‐furan protected‐maleimide terminated‐poly(methyl methacrylate) (PMMA‐MI) (M_n,GPC = 3100 g/mol, M_w/M_n = 1.31), or poly(ethylene glycol) (PEG‐MI) (M_n,GPC = 550 g/mol, M_w/M_n = 1.09), or a mixture of PMMA‐MI and PEG‐MI to yield well‐defined PC graft or hetero graft copolymers, PC‐g‐PMMA (M_n,TDGPC = 59000 g/mol, M_w/M_n = 1.22) or PC‐g‐PEG, or PC‐g‐(PMMA)‐co‐PC‐g‐(PEG) (M_n,TDGPC = 39900 g/mol, M_w/M_n = 1.16), respectively, using Diels–Alder click reaction in toluene at 110°C. The Diels–Alder grafting efficiencies were found to be over 97% using UV spectroscopy. Moreover, the structural analyses and the molecular weights of resulting graft copolymers were determined via ¹H NMR and triple detection GPC (TD‐GPC), respectively. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Sequential double polymer click reactions for the preparation of regular graft copolymers

In this study, graft copolymers with regular graft points containing polystyrene (PS) backbone and poly(methyl methacrylate) (PMMA), poly(tert‐butyl acrylate) (PtBA), or poly (ethylene glycol) (PEG) side chains were simply achieved by a sequential double polymer click reactions. The linear α‐alkyne‐ω‐azide PS with an anthracene pendant unit per chain was produced via atom transfer radical polymerization of styrene initiated by anthracen‐9‐ylmethyl 2‐((2‐bromo‐2‐methylpropanoyloxy)methyl)‐2‐methyl‐3‐oxo‐3‐(prop‐2‐ynyloxy) propyl succinate. Subsequently, the azide–alkyne click coupling of this PS to create the linear multiblock PS chain with pendant anthracene sites per PS block, followed by Diels–Alder click reaction with maleimide end‐functionalized PMMA, PtBA, or PEG yielded final PS‐g‐PMMA, PS‐g‐PtBA or PS‐g‐PEG copolymers with regular grafts, respectively. Well‐defined polymers were characterized by ¹H NMR, gel permeation chromatography (GPC) and triple detection GPC. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Block‐brush copolymers via ROMP and sequential double click reaction strategy

We report an efficient way, sequential double click reactions, for the preparation of brush copolymers with AB block‐brush architectures containing polyoxanorbornene (poly (ONB)) backbone and poly(ε‐caprolactone) (PCL), poly(methyl methacrylate) (PMMA) or poly(tert‐butyl acrylate) (PtBA) side chains: poly(ONB‐g‐PMMA)‐b‐poly(ONB‐g‐PCL) and poly(ONB‐g‐PtBA)‐b‐poly(ONB‐g‐PCL). The living ROMP of ONB affords the synthesis of well‐defined poly(ONB‐anthracene)₂₀‐b‐poly (ONB‐azide)₅ block copolymer with anthryl and azide pendant groups. Subsequently, well‐defined linear alkyne end‐functionalized PCL (PCL‐alkyne), maleimide end‐functionalized PMMA (PMMA‐MI) and PtBA‐MI were introduced onto the block copolymer via sequential azide‐alkyne and Diels‐Alder click reactions, thus yielding block‐brush copolymers. The molecular weight of block‐brush copolymers was measured via triple detection GPC (TD‐GPC) introducing the experimentally calculated dn/dc values to the software. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Triple Click Reaction Strategy for Macromolecular Diversity

This Feature Article focuses on the rapidly emerging concept of the “triple click reactions” towards the design and synthesis of macromolecules with well‐defined topology and chemical composition, and also precise molecular weight and narrow molecular weight distribution. The term “triple click reaction” used in this feature article is based on the utilization of three chemically and mechanistically different click reactions for polymer–polymer conjugation and post‐modification of the polymers. Three sequential click reactions of which two are identical should not be considered to be triple click reactions. The triple click reaction strategy for polymer conjugation and post‐modification of polymers is classified in this article based on the resultant architectures: linear and non‐linear structures.     

Diels‐alder click reaction for the preparation of polycarbonate block copolymers

The Diels‐Alder reaction as a click reaction strategy is applied to the preparation of well‐defined polycarbonate (PC)‐block copolymers. A well‐defined α‐anthracene‐terminated polycarbonate (PC‐anthracene) is prepared using 9‐anthracene methanol as an initiator in the ring opening polymerization of benzyl 5‐methyl‐2‐oxo‐1,3‐dioxane‐5‐carboxylate in CH₂Cl₂ at room temperature for 5 h. Next, a well‐defined α‐furan protected maleimide‐terminated‐poly(ethylene glycol) (PEG₁₁‐MI or PEG₃₇‐MI), ‐poly(methyl methacrylate) (PMMA₂₆‐MI), and ‐poly(ε‐caprolactone) (PCL₂₇‐MI) were clicked with the PC‐anthracene at reflux temperature of toluene to yield their corresponding PC‐based block copolymers (PC‐b‐PEG, PC‐b‐PMMA, and PC‐b‐PCL). The homopolymer precursors and their block copolymers were characterized by using the GPC, NMR and UV analysis. © 2013 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

Postfunctionalization of polyoxanorbornene via sequential Michael addition and radical thiol‐ene click reactions

We demonstrated the successful postfunctionalization of poly(oxanorbornene imide) (PONB) with two types of double bonds using sequential orthogonal reactions, nucleophilic thiol‐ene coupling via Michael addition and radical thiol‐ene click reactions. First, the synthesis of PONB with side chain acrylate groups is carried out via ring‐opening metathesis polymerization and nitroxide radical coupling reaction, respectively. Subsequently, the resulting polymer having two different orthogonal functionalities, main chain vinyl and side chain acrylate, is selectively modified via two sequential thiol‐ene click reactions, nucleophilic thiol‐ene coupling via Michael addition and photoinduced radical thiol‐ene. The orthogonal reactivity of two diverse double bonds, vinyl and acrylate functionalities, for the abovementioned consecutive thiol‐ene click reactions was first demonstrated on the model compound. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Graft copolymers via ROMP and Diels–Alder click reaction strategy

Anthracene‐functionalized oxanorbornene monomer and oxanorbornenyl polystyrene (PS) with ω‐anthracene end‐functionalized macromonomer were first polymerized via ring‐opening metathesis polymerization using the first‐generation Grubbs' catalyst in dichloromethane at room temperature and then clicked with maleimide end‐functionalized polymers, poly(ethylene glycol) (PEG)‐MI, poly(methyl methacrylate) (PMMA)‐MI, and poly(tert‐butyl acrylate) (PtBA)‐MI in a Diels–Alder reaction in toluene at 120 °C to create corresponding graft copolymers, poly(oxanorbornene)‐g‐PEG, poly(oxanorbornene)‐g‐PMMA, and graft block copolymers, poly(oxanorbornene)‐g‐(PS‐b‐PEG), poly(oxanorbornene)‐g‐(PS‐b‐PMMA), and poly(oxanorbornene)‐g‐(PS‐b‐PtBA), respectively. Diels–Alder click reaction efficiency for graft copolymerization was monitored by UV–vis spectroscopy. The dn/dc values of graft copolymers and graft block copolymers were experimentally obtained using a triple detection gel permeation chromatography and subsequently introduced to the software so as to give molecular weights, intrinsic viscosity ([η]) and hydrodynamic radius (R_h) values. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Multiarm star triblock terpolymers via sequential double click reactions

Multiarm star triblock terpolymers were obtained by using two different click reactions sequentially: Cu(I) catalyzed azide–alkyne and Diels–Alder. The synthetic strategy is described as follows: (poly(methyl methacrylate))_n‐(polystyrene)_m‐poly(divinyl benzene)) ((PMMA)_n‐(PS)_m‐polyDVB) multiarm star diblock copolymer was first obtained from an azide–alkyne click reaction of (alkyne‐PS)_m‐polyDVB multiarm star polymer with α‐anthracene‐ω‐azide PMMA (anth‐PMMA‐N₃), followed by a Diels–Alder click reaction of the anthracene groups at the star periphery with α‐maleimide poly (tert‐butyl acrylate) (PtBA‐MI) or α‐maleimide poly(ethylene glycol) (PEG‐MI) leading to target (PtBA)_k‐(PMMA)_n‐(PS)_m‐polyDVB and (PEG)_p‐(PMMA)_n‐(PS)_m‐polyDVB multiarm star triblock terpolymers. The hydrodynamic diameter of individual multiarm star triblock terpolymers were measured by dynamic light scattering (DLS) to be ～24–27 nm in consistent with the atomic force microscopy (AFM) images on silicon substrates. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1557–1564, 2010     

Heteroarm H‐shaped terpolymers through the combination of the Diels–Alder reaction and controlled/living radical polymerization techniques

Heteroarm H‐shaped terpolymers (PS)(PtBA)–PEO–(PtBA)(PS) and (PS)(PtBA)–PPO–(PtBA)(PS) [where PS is polystyrene, PtBA is poly(tert‐butyl acrylate), PEO is poly(ethylene oxide), and PPO is poly(propylene oxide)], containing PEO or PPO as a backbone and PS and PtBA as side arms, were prepared via the combination of the Diels–Alder reaction and atom transfer radical and nitroxide‐mediated radical polymerization routes. Commercially available PEO or PPO containing bismaleimide end groups was reacted with a compound having an anthracene functionality, succinic acid anthracen‐9‐yl methyl ester 3‐(2‐bromo‐2‐methylpropionyloxy)‐2‐methyl‐2‐[2‐phenyl‐2‐(2,2,6,6‐tetramethylpiperidin‐1‐yloxy)ethoxycarbonyl]propyl ester, with a Diels–Alder reaction strategy. The obtained macroinitiator with tertiary bromide and 2,2,6,6‐tetramethylpiperidin‐1‐oxy functional end groups was used subsequently in the atom transfer radical polymerization of tert‐butyl acrylate and in the nitroxide‐mediated free‐radical polymerization of styrene to produce heteroarm H‐shaped terpolymers with moderately low molecular weight distributions (<1.31). The polymers were characterized with ¹H NMR, ultraviolet, gel permeation chromatography, and differential scanning calorimetry. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3947–3957, 2006     

Multiarm star block and multiarm star mixed‐block copolymers via azide‐alkyne click reaction

The synthesis of multiarm star block (and mixed‐block) copolymers are efficiently prepared by using Cu(I) catalyzed azide‐alkyne click reaction and the arm‐first approach. α‐Silyl protected alkyne polystyrene (α‐silyl‐alkyne‐PS) was prepared by ATRP of styrene (St) and used as macroinitiator in a crosslinking reaction with divinyl benzene to successfully give multiarm star homopolymer with alkyne periphery. Linear azide end‐functionalized poly(ethylene glycol) (PEG‐N₃) and poly (tert‐butyl acrylate) (PtBA‐N₃) were simply clicked with the multiarm star polymer described earlier to form star block or mixed‐block copolymers in N,N‐dimethyl formamide at room temperature for 24 h. Obtained multiarm star block and mixed‐block copolymers were identified by using ¹H NMR, GPC, triple detection‐GPC, atomic force microscopy, and dynamic light scattering measurements. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 99–108, 2010     

Effects of Br connected groups on atom transfer nitroxide radical coupling reaction and its application in the synthesis of comb‐like block copolymers

The effects of Br connected groups on atom transfer nitroxide radical coupling (ATNRC) reaction were investigated. Two precursors methoxyl poly(ethylene oxide)‐b‐poly(ethylene oxide‐co‐2‐bromoiso butyryloxy glycidyl ether) (mPEO‐b‐Poly(EO‐co‐BiBGE)) and methoxyl poly(ethylene oxide)‐b‐poly(2‐bromoiso butyryloxy glycidyl ether) (mPEO‐b‐Poly(BiBGE)) with different ? C(CH₃)₂Br density were designed and synthesized firstly, and then ATNRC reaction were completed between these precursors and 2,2,6,6‐tetramethylpiperidinyl‐1‐oxy poly(ε‐caprolactone) (TEMPO‐PCL) in the presence or absence of St monomers, respectively. The results showed that the structure of Br connected groups showed an important effect on ATNRC reaction, and the ATNRC reaction with high efficiency could be realized by transforming the higher active Br connected groups into the lower one by the addition of small amount of St monomers. The final comb‐like block copolymers mPEO‐b‐[Poly(EO‐co‐Gly)‐g‐(St_1.8‐b‐PCL)] and mPEO‐b‐[Poly(Gly)‐g‐(St_2.4‐b‐PCL)] with high coupling efficiency were obtained by this strategy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1633–1640, 2010     

Quantification of ATRP initiator density on polymer latex particles by fluorescence labeling technique using copper‐catalyzed azide‐alkyne cycloaddition

We developed a novel fluorescence labeling technique for quantification of surface densities of atom transfer radical polymerization (ATRP) initiators on polymer particles. The cationic P(St‐CPEM‐C₄DMAEMA) and anionic P(St‐CPEM) polymer latex particles carrying ATRP‐initiating chlorine groups were prepared by emulsifier‐free emulsion polymerization of styrene (St), 2‐(2‐chloropropionyloxy)ethyl methacrylate (CPEM), and N‐n‐butyl‐N,N‐dimethyl‐N‐(2‐methacryloyloxy)ethylammonium bromide (C₄DMAEMA). ATRP initiators on the surface of polymer particles were converted into azide groups by sodium azide, followed by fluorescent labeling with 5‐(N,N‐dimethylamino)‐N′‐(prop‐2‐yn‐1‐yl)naphthalene‐1‐sulfonamide (Dansyl‐alkyne) by copper‐catalyzed azide‐alkyne cycloaddition (CuAAC). The reaction time required for both azidation of ATRP‐initiating groups and successive fluorescence labeling of azide groups with Dansyl‐alkyne by CuAAC were investigated in detail by FTIR and fluorescence spectral measurement, respectively. The ATRP initiator densities on the cationic P(St‐CPEM‐C₄DMAEMA) and anionic P(St‐CPEM) particle surfaces were estimated to be 0.21 and 0.15 molecules nm^?2, respectively, which gave close agreement with values previously determined by a conductometric titration method. The fluorescence labeling through click chemistry proposed herein is a versatile technique to quantify the surface ATRP initiator density both on anionic and cationic polymer particles. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4042–4051     

One‐pot double click reactions for the preparation of H‐shaped ABCDE‐type quintopolymer

We employed for the first time double click reactions: Cu(I) catalyzed azide‐alkyne 1,3‐dipolar cycloaddition and Diels–Alder (4 + 2) reactions for the preparation of H‐shaped polymer possessing pentablocks with different chemical nature (H‐shaped quintopolymer) using one‐pot technique. H‐shaped quintopolymer consists of poly(ethylene glycol) (PEG)‐poly(methylmethacrylate) (PMMA) and poly(ε‐caprolactone) (PCL)‐polystyrene (PS) blocks as side chains and poly (tert‐butylacrylate) (PtBA) as a main chain. For the preparation of H‐shaped quintopolymer, PEG‐b‐PMMA and PCL‐b‐PS copolymers with maleimide and alkyne functional groups at their centers, respectively, were synthesized and simply reacted in one‐pot with PtBA with α‐anthracene‐ω‐azide end functionalities in N,N‐dimethylformamide (DMF) using CuBr/N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA) as catalyst at 120 °C for 48 h. The precursors and the target H‐shaped quintopolymer were characterized comprehensively by ¹H NMR, UV, FTIR, GPC, and triple detection GPC. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 3409–3418, 2009     

Preparation of 3‐arm star polymers (A3) via Diels–Alder click reaction

Diels–Alder click reaction was successfully applied for the preparation of 3‐arm star polymers (A₃) using furan protected maleimide end‐functionalized polymers and trianthracene functional linking agent (2) at reflux temperature of toluene for 48 h. Well‐defined furan protected maleimide end‐functionalized polymers, poly (ethylene glycol), poly(methyl methacrylate), and poly(tert‐butyl acrylate) were obtained by esterification or atom transfer radical polymerization. Obtained star polymers were characterized via NMR and GPC (refractive index and triple detector detection). Splitting of GPC traces of the resulting polymer mixture notably displayed that Diels–Alder click reaction was a versatile and a reliable route for the preparation of A₃ star polymer. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 302–313, 2008