Thiol-Ene Click Chemistry for the Synthesis of Dendrimers

More recently, thiol-ene click chemistry has been applied in a very effective way for the synthesis of dendrimers. Hawker et al. (KiUops et al., 2008) were the first to describe the 

In contrast to the CuAAC reaction, the combination of thiol-ene chemistry with a traditional esterification reaction allowed for an efficient synthesis of dendrimers without the use of a metal catalyst. Moreover, as thiol-ene click can occur in the absence of solvent under benign reaction conditions, this reaction seems to be quite a promising alternative. 

In a similar way, Stenzel and coworkers (Chen et al., 2009) recently synthesized dendrimers by successive thiol-yne chemistry and esterification reactions. As for the thiol-ene case, it is an efficient process and does not require a metal catalyst. For the thiol-yne system, the reaction proceeds by reacting two equivalents of thiol with the alkyne, via a two-step process. Therefore, after the reaction, each alkyne functional group will be combined with two thiols, which is very attractive and advantageous in the synthesis of dendrimers. 

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