C(sp³)-CF₃ Reductive Elimination from a Five-Coordinate Neutral Copper(III) Complex.

Area of Science:

• Organometallic Chemistry
• Catalysis
• Synthetic Chemistry

Background:

• Reductive elimination from high-valent late-transition metals is crucial for C-C and C-heteroatom bond formation in catalysis.
• While studied for Pt(IV), Pd(IV), Ni(III)/Ni(IV), and Au(III), reductive elimination from neutral Cu(III) complexes is largely unexplored.

Purpose of the Study:

• To report the isolation and reactivity of a stable, neutral Cu(III) complex.
• To investigate the reductive elimination pathway from this novel Cu(III) complex for C-C bond formation.

Main Methods:

• Isolation and characterization of a five-coordinate, neutral square pyramidal Cu(III) complex.
• Quantitative yield determination of the reductive elimination product (CH3-CF3).
• Mechanistic studies to elucidate the reaction pathway.

Main Results:

• Successfully isolated a stable, five-coordinate, neutral square pyramidal Cu(III) complex.
• The Cu(III) complex underwent reductive elimination to yield CH3-CF3 in quantitative yield.
• Mechanistic studies indicated a synchronous bond-breaking/bond-forming process via a three-membered ring transition state.

Conclusions:

• Demonstrated the feasibility of reductive elimination from a neutral Cu(III) complex.
• Established a new synthetic route for C-C bond formation using copper catalysis.
• Provided mechanistic insight into the reductive elimination process involving a three-membered ring transition state.