Copper(II) anilides in sp³ C-H amination

Area of Science:

• Organometallic Chemistry
• Catalysis
• Organic Synthesis

Background:

• Copper complexes are versatile catalysts in organic transformations.
• β-diketiminato ligands offer tunable steric and electronic properties for metal complexes.
• C-H amination is a key reaction for introducing nitrogen functionalities into organic molecules.

Purpose of the Study:

• To synthesize and characterize novel β-diketiminato copper(II) anilides.
• To investigate the C-H amination activity of these copper complexes.
• To explore a new catalytic system for the synthesis of functionalized anilines.

Main Methods:

• Synthesis of copper(II) anilides from copper(II) t-butoxide and various anilines.
• Structural characterization using X-ray diffraction.
• Magnetic susceptibility and Electron Paramagnetic Resonance (EPR) spectroscopy.
• C-H amination reactions with hydrocarbons in the presence and absence of tert-butyl hydroperoxide.

Main Results:

• Novel copper(II) anilides with diverse bonding modes (κ(1)-N, bridging, κ(2)-N,N) were synthesized and characterized.
• Stoichiometric C-H amination was inefficient with the copper anilides alone.
• Rapid C-H amination was achieved using tert-butyl peroxide, indicating a radical pathway involving tert-butoxide radicals.
• The copper anilides act as radical scavengers, leading to functionalized anilines via a modified Kharasch-Sosnovsky reaction.

Conclusions:

• The synthesized β-diketiminato copper(II) anilides exhibit varied coordination behaviors.
• These complexes, in conjunction with peroxides, enable an efficient amino variant of the Kharasch-Sosnovsky reaction.
• The study presents a novel method for synthesizing functionalized anilines through copper-catalyzed C-H amination.