Metal-Catalysed A3 Coupling Methodologies: Classification and Visualisation

Fe3O4/PANI/CuI as a sustainable heterogeneous nanocatalyst for A3 coupling

The prepared copper iodide nanoparticles were impregnated on the support of ferrite nanoparticles functionalized with polyaniline, resulting in a magnetically recoverable heterogeneous nanocomposite. The activity of the prepared nanocomposite was investigated in the synthesis of propargylamine derivatives via A3 coupling under mild conditions. Techniques such as FESEM, EDAX, XRD, XPS, TEM, BET and FTIR were used to characterize the effective and unique heterogeneous Fe3O4/PANI/CuI nanocomposite developed in this work. This method used in the current study has several advantages, including a short reaction time, neat conditions, good product yield, ideal green matrices values, reusability for up to seven cycles, and magnetic retrievability.

Merging Cobalt-Catalyzed C-H Activation with the Mannich Reaction: A Modular Approach to α-Substituted N-Sulfonyl Amines

A three-component synthesis of α-substituted N-sulfonyl amines from aryl aldehydes, primary sulfonamides, and (hetero)arenes is described. This transformation enables a straightforward and modular synthesis of highly substituted sulfonamide scaffolds in good yields. The direct functionalization of C(sp2)-H bonds via cobalt-catalyzed C-H-activation offers an appealing and atom-economical alternative to classical methods for the synthesis of α-arylated amines such as the Petasis or Mannich-type reactions.

Clay based heterogeneous catalysts for carbon-nitrogen bond formation: a review

Clay and modified clay-based catalysts are widely used in organic transformation. Owing to the interlayer ions and good ion exchange capacity of clay, replacement with another ion and incorporation of different nanomaterials can be done. Due to these significant properties of clay, it can be utilized in the synthesis of various organic compounds. Carbon-nitrogen bonded compounds possess diverse applications in different fields. These compounds are prepared using different solid acid heterogeneous catalysts. This review presents a detailed discussion on clay used for the carbon-nitrogen bond formation reaction, such as the Biginelli reaction and A3 and KA2 coupling reactions. Additionally, other C-N bond formation reactions using various clay-based catalysts such as bentonite, montmorillonite, hydrotalcite and halloysite clay with various metals, metal oxides, Kegging type heteropoly acid and various nanomaterial incorporated clay heterogeneous catalysts are discussed.

Chemical Chartographisis: a contemporary perspective in molecular design and synthesis

The use of flexible molecular systems in solution, without strictly controlling their behaviour, has frequently been productive. Their potential could increase by a more holistic view of the reaction(s) process(es) in which they are involved. In this perspective, we introduce a broader approach - "Chemical Chartographisis" - and discuss three projects in detail to illustrate its potential. The topics involve bimetallic 3d/4f species and coordination compounds built from benzotriazole-based and (a)symmetric salan ligands and focus on catalytic and, in less detail, biological-related examples.

Deciphering the Primary Role of Au⋅⋅⋅H-X Hydrogen Bonding in Gold Catalysis

Au⋅⋅⋅H-X (X=N or C) hydrogen bonding is gaining increasing interest, both in the study of its intrinsic nature and in their operability in different fields. While the role of these interactions has been studied in the stabilization of gold(I) complexes, their role during the minimum free energy reaction pathway of a given catalytic process remains unexplored. We report herein that complex [Au(C≡CPh)(pip)] (pip=piperidine) catalyses the A3 -coupling reaction for the synthesis of propargylamines, thanks to the ability of Au(I) to promote weak hydrogen bonding interactions with the reactants along the free energy profile. Density Functional Theory (DFT) calculations show that these Au⋅⋅⋅H-X interactions play a directing role in the catalysed A3 -coupling. Topological non-covalent interactions (NCI), interaction region indicator (IRI) and quantum theory of atoms in molecules (QTAIM) analysis in real space of the electron density provide a description of these interactions accurately.