N-aryl pyrazole is a prevalent motif among pharmaceuticals across various therapeutic areas but can be challenging to synthesize due to the high similarity of the two nitrogen atoms. Now it has been shown that the use of copper catalysis and arynes provides a switchable protocol to access both regioisomers.

Catalytic access to axially chiral diaryl ethers remains limited by the difficulty of enantioselective C–O bond formation. Now peptide-mimic phosphonium salts enable atroposelective nucleophilic aromatic substitution-driven C–O bond construction, affording axially enantioenriched diaryl ethers.

Diazo compounds are among the most versatile intermediates in organic synthesis, enabling high-value transformations such as cyclopropanation, X–H insertion, and heterocycle formation. However, their intrinsic instability and hazardous nature have severely restricted their practical use, particularly at scal