RAFT agent synthesis

Currently, few RAFT agents are commercially available. However, RAFT agents are available in moderate to excellent yields by a variety of methods and 

Some of the methods exploited in recent work include  

Often this will involve sequential treatment of an anionic species with carbon disulfide and an alkylating agent in a one-pot reaction. For example, the process was used to prepare benzyl dithiobenzoate 

Addition of ditliioacids to electron-deficient monomers (MA, MMA, AN) proceeds by Michael addition to pul sulfur at the unsubstitiited end of the double bond/  

Various side reactions may complicate RAFT polymerization. Transfer to solvents, monomer and initiator occur as in conventional radical polymerization. Other potential side reactions involve the intermediate radicals 165 and 167. These radicals may couple with another radical (Q ) to form 271 or disproportionate with Q to form 270. They may also react with oxygen. The intermediate radicals 165 and 167 are not known to add monomer. 

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RAFT agent Synthesis Polymerizations RAFT agenf Synthesis Polymerizations ... 

RAFT agent Synthesis Polymerization RAFT agent Synthesis Polymerization ... 

Scheme 6.17 Major methods used for RAFT agent synthesis (RX = alkylating agent, LR = Lawesson s reagent or equivalent).

Also, Kerep and Ritter reported a radical chain transfer agent as a dual initiator, FRP-1 [45]. The first step builds on the fact that hydroxyl groups are much better nucleophiles in enzymatic ROP than thiols. Due to the chemoselectivity of the enzyme, PCLs with predominantly thiol endgroups were obtained, which were subsequently used as macroinitiator for styrene. The authors report that the reaction yield can be further increased by microwave irradiation. Although thiols provide less control over the radical polymerization than RAFT agents, the subsequent radical polymerization successfully leads to the synthesis of PCL-Z -PS. 

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