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Palladium N-Heterocyclic Carbene-Catalyzed Aminations: An Outline

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Abstract

Amination reactions play a pivotal role in synthetic organic chemistry, facilitating the generation of nitrogen-containing scaffolds with broad applications in drug synthesis, material production, polymer formation, and the generation of amino acids and peptides. Amination offers the potential to fine tune the properties of natural products and produce functional materials for various applications. Palladium N-heterocyclic carbene (Pd–NHC) emerges as an innovative and highly effective catalyst in this context. Under favorable reaction conditions, this robust and simple catalyst efficiently facilitates the synthesis of a diverse range of compounds with varying complexity and utility. Pd–NHC complexes exhibit significant σ-electron donating potential, enhancing the ease of the oxidative addition process in their mechanistic pathway. Their steric topography further contributes to a rapid reductive elimination. These complexes demonstrate remarkable stability, a result of the strong Pd–ligand bond. The wide variety of Pd–NHC complexes has proven highly efficient in catalyzing reactions across a spectrum of complexities, from simple to intricate. The domain of aminations catalyzed by Pd–NHC has undergone significant diversification, presenting new opportunities, particularly in the realms of material chemistry and natural product synthesis. This review outlines the advancements in Pd–NHC-catalyzed amination reactions, covering literature up to date.

Graphical Abstract

Palladium (Pd) N-heterocyclic carbenes (NHCs) have amassed high recognition recently. They are efficient complexes with tuneable complexities promoting catalysis significantly. Amination reactions have paved way toward the formation of C–N bonds and, in turn, realizing structurally relevant molecules in organic chemistry. Inspired by these facets, we have tried to encompass in this review, the developments in Pd–NHC-catalyzed amination reactions and carries reports up to date.

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Abbreviations

acac:

Acetylacetonate

BIAN:

Acenaphthoimidazolylidene

Br:

Bromide

Cl:

Chloride

2 or 3-ClPy:

2 or 3-Chloropyridine

3-ClTh:

3-Chlorothiophene

Co:

Cobalt

Cs2CO3 :

Cesium carbonate

Cu:

Copper

DME:

Dimethoxyethane

DMF:

Dimethylformamide

equiv.:

Equivalence

Fe:

Iron

h:

Hour

H2O:

Water

K2CO3 :

Potassium carbonate

K3PO4 :

Potassium phosphate

KHMDS:

Potassium hexamethyldisilazide

KOtAm:

Potassium tert-amylate

KOtBu:

Potassium tert-butoxide

LiOtBu:

Lithium tert-butoxide

min.:

Minutes

Mn:

Manganese

Ni:

Nickel

Pd:

Palladium

Pd–NHC:

Palladium N-heterocyclic carbene

Pd–PEPPSI:

Palladium–pyridine, enhanced, precatalyst preparation, stabilization, and initiation

PS-Pd–NHC:

Polymer supported-palladium N-heterocyclic carbene

RT:

Room temperature

THF:

Tetrahydrofuran

THP:

Tetrahydropyran

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Acknowledgements

M.N. thanks the University Grants Commission (UGC-New Delhi) for the award of a senior research fellowship

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Authors and Affiliations

  1. School of Physical Sciences, Amrita Vishwa Vidyapeetham, Amritapuri Campus, Clappana P. O., Kollam, Kerala, 690525, India

    S. B. Umabharathi

  2. School of Chemical Sciences, Mahatma Gandhi University, Priyadarsini Hills P. O., Kottayam, Kerala, 686560, India

    Mohan Neetha & Gopinathan Anilkumar

  3. Institute for Integrated Programs and Research in Basic Sciences (IIRBS), Mahatma Gandhi University, Priyadarsini Hills P. O., Kottayam, Kerala, 686560, India

    Gopinathan Anilkumar

  4. Advanced Molecular Materials Research Center (AMMRC), Mahatma Gandhi University, Priyadarsini Hills P. O., Kottayam, Kerala, 686560, India

    Gopinathan Anilkumar

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Umabharathi, S.B., Neetha, M. & Anilkumar, G. Palladium N-Heterocyclic Carbene-Catalyzed Aminations: An Outline. Top Curr Chem (Z) 382, 3 (2024). https://doi.org/10.1007/s41061-024-00449-w

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