A reflection on recent advances in organometallic copper(iii) chemistry.

This commentary provides a broad perspective on recent advances in organometallic copper(iii) chemistry, building on the review we published in 2013 (A. Casitas and X. Ribas, Chem. Sci., 2013, 4, 2301, https://doi.org/10.1039/C3SC21818J). Parallel with major developments in copper-catalyzed bond-forming reactions, research has increasingly focused on understanding the reactivity of organocopper(iii) complexes. The detailed mechanistic picture tightly depends on the system studied, thus posing challenges to tame the promiscuous behavior of copper catalysis. At the same time, ongoing discussion regarding the formal +3 oxidation state in these compounds, especially those bearing CF3 ligands, has provided a deeper understanding of their electronic structures.