This method comes to us from Switzerland’s very own Ecole Polytechnique Fédérale de Lausanne, group of Dr. Waser. They decided to functionalize Tyrosine using Hypervalent Iodine compounds. To be precise, they used ethynylbenziodoxolones (EBX). It was pretty selective to Tyrosine, compared to other nucleophilic residues, and was slightly reactive towards cysteine. But, if there is reactive cysteine, everybody knows what to do.
They also did some buffer optimization and in 100mM Tris they got 99% conversion!
There are a lot of interesting applications that they described in this article and definitely worth adding to the collection of any serious Bioconjugation Chemist.
Article is available for free download here:
https://pubs.rsc.org/en/content/articlepdf/2022/sc/d2sc04558c