186354-48-3

Usage

Type of compound

imidazolium compound

Contains

a chloride ion

Common uses

organic synthesis and catalysis as a chiral ligand

Potential uses

asymmetric catalysis and as a building block in the synthesis of chiral molecules

Promise

in the development of new materials and pharmaceuticals

Versatility

various applications in the field of chemistry and materials science.

Upstream product

• 50-00-0 formaldehyd 
• 131543-46-9 Glyoxal 
• 3886-70-2 (R)-1-(1-Naphthyl)ethylamine 
• 10420-89-0 (S)-1-(1-Naphthyl)ethylamine 
• 141734-24-9 N,N'-bis[(S)-1-naphthyl-ethyl]ethanediimine 

Relevant academic research and scientific papers

Nickel-Catalyzed Enantioselective Arylative Activation of Aromatic C-O Bond

The pioneering nickel-catalyzed cross-coupling of C-O electrophiles was unlocked by Wenkert in the 1970s; however, the transition-metal-catalyzed asymmetric activation of aromatic C-O bonds has never been reported. Herein the first enantioselective activation of an aromatic C-O bond is demonstrated via the catalytic arylative ring-opening cross-coupling of diarylfurans. This transformation is facilitated via nickel catalysis in the presence of chiral N-heterocyclic carbene ligands, and chiral 2-aryl-2′-hydroxy-1,1′-binaphthyl (ArOBIN) skeletons are delivered axially in high yields with high ee. Moreover, this versatile skeleton can be transformed into various synthetic useful intermediates, chiral catalysts, and ligands by using the CH- and OH-based modifiable sites. This chemistry features mild conditions and good atom economy.

Synthesis, Characterization, and Catalytic Activity of Chiral NHC Platinum(II) Pyridine Dihalide Complexes

A series of platinum(II) dihalide pyridine complexes bearing chiral C2-symmetric N-heterocyclic carbene (NHC) ligands [Pt(NHC*)(Py)(Hal)2] was synthesized in a one-pot procedure and characterized by NMR spectroscopy and single crystal X-ray diffraction (SC-XRD). The complexes were tested for the asymmetric cycloisomerization of enynol into bicyclo[3.1.0]hexanone and feature an excellent catalytic activity at room temperature along with a modest enantiomeric induction (up to 39% ee).

Supported Au Nanoparticles with N -Heterocyclic Carbene Ligands as Active and Stable Heterogeneous Catalysts for Lactonization

Attachment of N-heterocyclic carbenes (NHCs) on the surface of metal nanoparticle (NP) catalysts permits fine-tuning of catalytic activity and product selectivity. Yet, NHC-coated Au NPs have been seldom used in catalysis beyond hydrogenation chemistry. One challenge in this field has been to develop a platform that permits arbitrary ligand modification without having to compromise NP stability toward aggregation or leaching. Herein, we exploit the strategy of supported dendrimer-encapsulated metal clusters (DEMCs) to achieve aggregation-stable yet active heterogeneous Au NP catalysts with NHC ligands. Dendrimers function as aggregation-inhibitors during the NP synthesis, and NHCs, well-known for their strong attachment to the gold surface, provide a handle to modify the stereochemistry, stereoelectronics, and chemical functionality of the NP surface. Indeed, compared to ligandless Au NPs which are virtually inactive below 80 °C, the NHC-ligated Au NP catalysts enable a model lactonization reaction to proceed at 20 °C on the same time scale (hours). Based on Eyring analysis, proto-deauration is the turnover-limiting step accelerated by the NHC ligands. Furthermore, the use of chiral NHCs led to asymmetric induction (up to 16% enantiomeric excess) in the lactonization transformations, which demonstrates the potential of supported DEMCs with ancillary ligands in enantioselective catalysis.

Some insights into the gold-catalysed A3-coupling reaction

A series of cyclometallated and functionalised NHC gold(I) and gold(III) complexes, many of which feature chiral ligands, and their application to A3-coupling reactions is presented. Gold(III) complexes were found to be particularly effective catalysts for the coupling in a range of solvents, however no asymmetric induction was obtained when using chiral gold complexes and the rate of product formation was found to be similar even when using different ligand systems. In-situ NMR analysis of these reactions indicates that decomposition of the catalyst occurs during the course of the reaction while TEM studies revealed the presence of gold nanoparticles in crude reaction mixtures. Taken together these data suggest that the gold nanoparticles, rather than the intact gold complexes, could be the catalytically active species, and if so this may have significant implications for other gold-catalysed systems.

Solvent effects in gold-catalysed A3-coupling reactions

Gold-catalysed A3-reactions proceed efficiently when conducted in 2,2,2-trifluoroethanol as solvent. The rates of these reactions are accelerated considerably when conducted in a microwave reactor.

Enantioselective copper catalysed 1,4-conjugate addition reactions using chiral N-heterocyclic carbenes

The preparation of a variety of chiral N-heterocyclic carbene (NHC) precursors is described. The relative merits of imidazolinium salts and silver carbenes as NHC precursors are discussed with respect to their synthesis, stability and performance in the copper catalysed conjugate addition of dialkyl zinc reagents to a variety of Michael acceptors. Enantioselectivities of up to 93% were achieved using as little as 4% of chiral ligand.

Chirale Heterocyclencarbene in der asymmetrischen Homogenkatalyse

Keywords: Asymmetrische Katalyse; Carbenkomplexe; Homogene Katalyse; Hydrosilylierung; Rhodiumkomplexe