Mmm, a reaction sandwich…︁ Using an immunoassay‐based technique able to monitor any kind of cross‐coupling reaction, a systematic and rapid evaluation of a large panel of random reactions was carried out. This approach led to the discovery of two new copper‐promoted reactions: a desulfurization reaction of thioureas leading to isoureas and a cyclization reaction leading to thiazole derivatives from
An immunoassay‐based method was used to screen numerous combinations of dipoles and dipolarophiles for their ability to undergo chemoselective and biocompatible [3+2] cycloaddition reactions. The approach fulfills most of the requirements of the click concept and led to the discovery of a copper‐catalyzed reaction that generates pyrazoles from sydnone and alkyne reagents.