Homogeneous cobalt-catalyzed reductive amination for synthesis of functionalized primary amines

Area of Science:

• Catalysis
• Organometallic Chemistry
• Sustainable Chemistry

Background:

• Developing earth-abundant 3d metal catalysts is crucial for chemical research.
• Designing base metal complexes for reductive amination to produce primary amines is challenging.

Purpose of the Study:

• To report a molecularly-defined non-noble metal catalyst for primary amine synthesis.
• To achieve efficient synthesis of diverse primary amines from carbonyl compounds.

Main Methods:

• Utilized a combination of cobalt and linear-triphos (bis(2-diphenylphosphinoethyl)phenylphosphine) as the catalyst.
• Employed carbonyl compounds, gaseous ammonia, and hydrogen as reactants.
• Proposed an inner-sphere mechanism supported by density functional theory (DFT) computations.

Main Results:

• Successfully synthesized linear and branched benzylic, heterocyclic, and aliphatic primary amines in good to excellent yields.
• The cobalt catalyst demonstrated high selectivity, enabling the introduction of the -NH2 moiety into functionalized and diverse molecules.
• Identified H2 metathesis as the rate-determining step in the proposed catalytic cycle.

Conclusions:

• The cobalt-linear-triphos system serves as an effective molecularly-defined non-noble metal catalyst for primary amine synthesis.
• The catalyst's high selectivity and efficiency contribute to the advancement of sustainable amine production.
• The proposed inner-sphere mechanism provides insights into the catalytic process.