Design and Synthesis of Novel “Orthogonally” Functionalizable Maleimide‐Based Styrenic Copolymers

Abstract

Polymers containing maleimide groups on their side chains have been synthesized by utilization of a novel styrenic monomer containing a masked-maleimide unit. AIBN initiated free radical polymerization and reverse addition-fragmentation chain transfer (RAFT) polymerization was utilized for synthesis of copolymers containing masked maleimide groups as side chains. The maleimide groups were unmasked via the retro Diels-Alder reaction. Orthogonally functionalizable copolymers were obtained by copolymerization of the maleimide-based monomer with other reactive monomers to yield copolymers that are reactive towards thiol- and amine-containing molecules, or two different thiol-containing molecules sequentially via the nucleophilic thiol-ene and the free-radical thiol-ene "click" reactions.

Orthogonal multiple click reactions in synthetic polymer chemistry

“…More recently, Sanyal and Tunca groups demonstrated this combination for the orthogonal functionalization of polymer backbone. Sanyal group prepared the random PS copolymer ( M n,GPC = 5400 g/mol, PDI = 1.60) with pendant alkene‐ and MI‐functional groups via free radical polymerization .…”

“…More recently, Sanyal and Tunca groups demonstrated this combination for the orthogonal functionalization of polymer backbone. Sanyal group prepared the random PS copolymer ( M n,GPC = 5400 g/mol, PDI = 1.60) with pendant alkene‐ and MI‐functional groups via free radical polymerization . In a subsequent reaction, furan protection is removed via retro‐Diels‐Alder to yield the PS with pendant alkene and maleimide that is successively functionalized with two different thiols via Michael and UV‐initiated radical thiol‐ene reactions.…”

“…Sanyal group designed a PS copolymer backbone ( M n,GPC = 3800 g/mol, PDI = 1.50) possessing orthogonal functional groups: maleimide and active ester group based on succinimide . Selective stepwise functionalization of the copolymer was accomplished by reacting it with 11‐undecenethiol, followed by 3‐amino‐1‐propanol using Michael thiol‐ene and activated ester reactions, respectively.…”

Synthesis of Activated Ester Functional Polyesters through Light‐Induced [4+4] Cycloaddition Polymerization

“…[5][6][7][8][9][10][11][12][13][14][15] Besides the abovementioned photoswitching ability, the anthracene has another unique feature which abilities have been prepared by employing the activated ester substitution reactions. [33][34][35][36][37][38][39][40] It is well known that preparing a polymer under mild condition is always desirable. In line with this idea, the light-induced cycloaddition polymerization has some unique features, such as that the polymerization could be performed both under an additive free condition and at room temperature.…”

Side‐Chain Modification and “Grafting Onto” via Olefin Cross‐Metathesis

“…Furthermore, initiating sites can be introduced enabling the growth of polymeric chains in a “grafting‐from” approach 3. The literature dealing with the functionalization of polymers with small molecules is vast, and some recent studies include the use of azide–alkyne cycloaddition,4, 5 thiol‐ene addition,6, 7 amidation,8 thia‐michael addition,9 epoxide ring‐opening with thiols,10 and amines11 among many others 12. On the other hand, the “grafting‐onto” method has been extensively applied in the synthesis of graft (co‐)polymers using esterifications,13 azide–alkyne cycloadditions,14, 15 Diels–Alder cycloadditions,16, 17 thiol‐ene additions,18 and others.…”