Organocopper(III) Compounds with Well‐defined Structures Undergo Reductive Elimination to Form C—C or C–Heteroatom Bonds

Reductive elimination around Cu(III) atom arises an increasing attention, since this organometallic pathway has been often proposed in a range of Cu‐based reactions. However, due to limited organocopper(III) compounds with well‐defined structures, this elementary reaction still remains an extremely challenging issue. In this review, structurally well‐defined organocopper(III) compounds are mainly divided into three classes based on their ligands: perfluoromethyl Cu(III) compounds, macrocyclic ligand‐based aryl‐Cu(III) compounds, and spiro organocopper(III) compounds chelated by bidentate ligands. The majority of organocopper(III) compounds display the typical square planar geometry. There also exist a few penta‐coordinated organocopper(III) complexes, which share a weak apical Cu‐L bond. In order to form a cis Cu(III)–C and Cu(III)–Nu bonding geometry required for reductive elimination, the re‐arrangement of coordination modes around tetra‐coordinated Cu(III) atoms is necessary. For the aryl‐Cu(III) cationic complexes with one Cu(III)–C bond, the re‐arrangement is triggered by the coordination of the fifth ligand (solvent or nucleophiles), while for the tetra‐carbon‐coordinated organocuprate(III) compounds, the process might be realized via the cleavage of one Cu(III)–C bond by attack of electrophiles. Stoichiometric and catalytic reactions involving well‐defined organocopper(III) compounds to form C—C or C–heteroatom bonds are discussed to support their intermediacy.