A novel reaction involving benzoxazole, ethyl diazoacetate, and water has been discovered, with TpBr3Cu­(NCMe) (TpBr3 = hydrotris­(3,4,5-tribromopyrazolyl)­borate) as the catalyst. The fused azoles are converted into highly functionalized substituted benzenes bearing aldehyde, amine carboxylate and hydroxyl groups. The protocol has been applied for a series of benzoxazoles with several diazo compounds. Experimental data and theoretical calculations have led to a mechanistic proposal that includes carbene addition, ylide formation, and water addition to the latter, all those steps being catalyzed by the copper center.

The renaissance on the application of gem‐diborylalkanes from 2010, has allowed the conquest of new synthetic application towards C−C and C−N bond formation. The activation of gem‐diborylalkanes by Cu(I) catalysts, generates active borylalky copper(I) species that are able to trap several electrophilic reagents, in an efficient way. In addition, the modification of Cu(I) complexes with chiral ligands, induces asymmetric platforms towards the synthesis of enantioenriched organoboron compounds.