Numerous reports invoke Cu III -F intermediates engaging in oxidative cross-couplings mediated by low/mid valent copper and formal sources of "F + " oxidants. These elusive and typically instable Cu III fluorides have been rarely characterized or spectroscopically identified, making their existence and participation within catalytic cycles somehow questionable. We have authenticated a stable organocopper(III) fluoride that undergoes Csp-CF3 bond formation upon addition of silyl-capped alkynes following a 2e -Cu III /Cu I redox shuttle. This finding strongly supports the intermediacy of Cu III fluorides in C-C coupling. We review herein the State of the Art about well-defined Cu III fluorides enabling cross-coupling reactions. 1 Introduction 2 Brief history of coupling competent Cu III fluorides 3 Design of an isolable -yet reactive-organocopper(III) fluoride 4 Alkyne trifluoromethylation: scope and mechanism 5 Extension to aryl-CF3 and C-heteroatom couplings 6 Summary and outlook Key words Trifluoromethylation, organocopper(III) compounds, Cu III fluorides, oxidative cross-coupling, 2e -redox shuttle. Scheme 1. State of art and concept disclosed herein. Schematic representation of the oxidative trifluoromethylation of (hetero)aryls or alkynes enabled by high-valent copper (top). Selected trifluoromethylating Cu III CF3 platforms I-XI prepared through Cu I -to-Cu III oxidation triggered by air, O2, AgF or aryl-radicalenabled oxidative addition of alkyl iodides (middle)

. 5-7,10-13 Entry to the Cu III -F 1 and its application in trifluoromethylation via transmetallation reaction with silyl-capped alkynes and related compounds (bottom).

Given the synthetic utility of alkynes, a singular case example of oxidative trifluoromethylation is represented by their selective