One‐pot deprotection and functionalization of polythiol copolymers via six different thiol–X reactions

Abstract

Thiol chemistry is a versatile and powerful tool for the preparation of functional polymers and materials via post-polymerization modification. However, polythiols are generally difficult to handle since they are prone to gel formation due to oxidative coupling between pendant thiol groups to form disulfide bridges. One-pot deprotection and functionalization procedures that avoid polythiol manipulation are therefore attractive. In that regard, a methacrylate monomer carrying a xanthate moiety was used to prepare protected polythiol copolymers via concurrent atom transfer radical polymerization/reversible addition-fragmentation chain transfer. One-pot deprotection and functionalization were carried out via aminolysis with a primary amine and subsequent functionalization without isolating the intermediate polythiols. Functionalization was exemplified with six different thiol-X reactions. Thiol-ene radical addition was not conclusive since it led to partial gelation. However, one-pot deprotection and functionalization via thiol-halogen nucleophilic substitution, thiol-epoxy ring opening, thiol-isocyanate reaction, thiol-acrylate Michael addition and thiol-disulfide exchange were quantitative and led to well-defined polymers.

Regioselective C−H Xanthylation as a Platform for Polyolefin Functionalization

“…Xanthates also provide facile access to the thiol functional group by aminolysis or hydrolysis.Characterization by 1 Hand 13 CNMR, FT-IR spectroscopy,and GPC confirmed cleavage of the xanthylate upon aminolysis.T he revealed thiol represents av aluable group for diversifying polyolefin functionality. [27] Michael addition of the thiol to an acrylate or acrylamide can be used to install arange of valuable groups (Figure 3). Fori nstance,a dhesive catechol groups (4)a re valuable in composite materials, [28] and multifunctional acrylates can be employed to create polyolefin thermosets or elastomers (5).…”

Protected thiol strategies in macromolecular design

“…The same research group [24] subsequently reported on the one-pot deprotection and functionalization of protected polythiol copolymers through various thiol-X chemistries ( Figure 5). This was achieved through the concurrent ATRP/RAFT polymerization of the same methacrylate monomer containing a xanthate moiety.…”

“…However, together with the increased use of thiol-related chemistries in polymer science, the necessity for protected thiol strategies became increasingly more prevalent. Many researchers have tackled this challenge by choosing a method applicable to their system as mentioned in recent reviews, feature articles or books [24,36,48]. However, to the best of our knowledge, no review was presenting a comprehensive, in-depth overview of all the possible strategies including their advantages and drawbacks.…”

“…Indeed, thiols are very reactive molecules, used either as strongly nucleophilic thiolate anion, or as electrophilic thiyl radical. As a consequence, a broad variety of substrates is accessible for reaction [22,23], which could all be gathered in a toolbox of available thiol-X reactions ( 1) [24,25]. M a n u s c r i p t 3 It should be noted that although efficient transformations involving thiols have risen to an unprecedented level of popularity during the last years, thiol chemistry has always been important in macromolecular synthesis.…”

Facile method towards functionalization of partially fluorinated polyarylethers via sequential post-polymerization modification

“…However, major drawbacks whereby the functional groups in monomers may retard efficient polymerization or competitively participate in side reactions that can lead to the loss of respective functional properties [15]. Up until now, the functional groups that can be successfully incorporated into a fluoropolymer backbone through the direct polymerization method are very limited [16]. Further, when highly complex functional structures are required, it can be difficult to synthesize the corresponding functional monomers.…”