Metal-N-Heterocyclic Carbene Complexes in Buchwald-Hartwig Amination Reactions

Area of Science:

• Organic Chemistry
• Catalysis
• Medicinal Chemistry

Background:

• Buchwald-Hartwig amination is a vital method for forming carbon-nitrogen (C-N) bonds.
• N-heterocyclic carbene (NHC)-transition metal complexes have emerged as powerful catalysts for this transformation.

Purpose of the Study:

• To provide a comprehensive review of Buchwald-Hartwig amination mediated by NHC-transition metal complexes.
• To cover literature from 1999 to December 2024, highlighting key developments and applications.

Main Methods:

• Focus on palladium- and nickel-NHC complexes, with examples of cobalt and rhodium systems.
• Discussion of coupling reactions involving a wide range of amines and electrophiles, including challenging functional groups.

Main Results:

• Detailed presentation of NHC-ligated palladium and nickel complexes as efficient catalysts.
• Demonstration of the utility of these complexes in coupling conventional and novel substrates like aryl fluorides and methyl ethers.
• Inclusion of challenging functional groups such as amides, esters, and sulfoxides.

Conclusions:

• NHC-metal complexes play a crucial role in constructing C-N bonds via Buchwald-Hartwig amination.
• These catalytic systems are indispensable tools in medicinal chemistry, materials science, and drug discovery.