Copper(ii) ketimides in sp³ C-H amination

Area of Science:

• Organometallic Chemistry
• Catalysis
• Synthetic Chemistry

Background:

• Benzophenone imine is a common organic compound.
• Copper complexes are widely used in catalysis.
• β-diketiminate ligands are known for stabilizing metal centers.

Purpose of the Study:

• To synthesize and characterize novel copper(II) ketimide complexes.
• To investigate the reactivity of these complexes with alkyl radicals.
• To develop a catalytic protocol for sp3 C-H amination using these complexes.

Main Methods:

• Reaction of benzophenone imine with copper(II) tert-butoxide complexes.
• Structural characterization using X-ray crystallography.
• Radical capture experiments.
• Catalytic C-H amination reactions.

Main Results:

• Isolable copper(II) ketimides were formed, with a three-coordinate complex showing a short Cu-N bond and a linear Cu-N-C linkage.
• Copper(II) ketimides captured alkyl radicals, forming N-alkylated products.
• A catalytic system for sp3 C-H amination was developed, yielding N-alkyl ketimines.
• The N-alkyl ketimines were readily converted to primary amines via acidic deprotection.

Conclusions:

• Novel copper(II) ketimide complexes are accessible and exhibit interesting structural features.
• These complexes can participate in radical capture and serve as key intermediates in catalytic C-H amination.
• The developed protocol offers a new method for functionalizing unactivated sp3 C-H bonds and synthesizing primary amines.