Synthesis of thiol functionalized poly(meth)acrylates through enzymatic catalysis and a subsequent one pot reaction process

The synthesis and modification of thiol functionalized poly(meth)acrylates using a straightforward reaction concept that consists of an enzymatically catalyzed monomer synthesis, free radical polymerization and post-polymerization modification is presented. The well-known enzymatic transacylation of methyl acrylate and methyl methacrylate that runs under mild and environmentally friendly conditions was used to synthesize thiol protected acrylic and methacrylic monomers. Upon free radical polymerization and subsequent removal of protection groups, polymers with pendant thiol groups are obtained, which, in turn, can react in situ with Michael acceptors to form thiol-ene reaction products. The exceptional advantage of the proposed method is that upon removal of the enzyme from the monomer mixture, the polymerization, deprotection of thiols and subsequent Thio-Michael-type addition reaction can be conducted in one pot without purification of the intermediate products. Furthermore, the different reactivities of acetyl and benzoyl protection groups in lipase catalyzed reactions are discussed.

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► Novozyme 435® as catalyst for enzymatic transacylations of methyl(meth)acrylate.
► Acetyl groups are not suitable as thiol protection groups in enzymatic reactions.
► Poly(meth)acrylates with pendant protected thiol groups prepared by free radical polymerization.
► Poly(meth)acrylates with pendant thiol groups for thiol-ene ‘click’ reactions.
► Polymerization, deprotection and thiol-ene ‘click’ occurs in one pot.