Chiral Ferrocene Derivatives Research Articles

Synthesis of Planar Chiral Compounds Containing α-Amino Phosphonates for Antiplant Virus Applications against Potato Virus Y.

An unprecedented study of the application of planar chiral compounds in antiviral pesticide development is reported. A class of multifunctional planar chiral ferrocene derivatives bearing α-amino phosphonate moieties was synthesized. These compounds, exhibiting superior optical purities, were subsequently subjected to antiviral evaluations against the notable plant pathogen potato virus Y (PVY). The influence of the absolute configurations of the planar chiral compounds on their antiviral bioactivities was significant. A number of these enantiomerically enriched planar chiral molecules demonstrated superior anti-PVY activities. Specifically, compound (Sp, R)-9n displayed extraordinary curative activities against PVY, with a 50% maximal effective concentration (EC50) of 216.11 μg/mL, surpassing the efficacy of ningnanmycin (NNM, 272.74 μg/mL). The protective activities of compound (Sp, R)-9n had an EC50 value of 152.78 μg/mL, which was better than that of NNM (413.22 μg/mL). The molecular docking and defense enzyme activity tests were carried out using the planar chiral molecules bearing different absolute configurations to investigate the mechanism of their antiviral activities against PVY. (Sp, R)-9n, (Sp, R)-9o, and NMM all showed stronger affinities to the PVY-CP than the (Rp, S)-9n. Investigations into the mechanisms revealed that the planar chiral configurations of the compounds played pivotal roles in the interactions between the PVY-CP molecules and could augment the activities of the defense enzymes. This study contributes substantial insights into the role of planar chirality in defending plants against viral infections.

Comparison of Diastereoselective ortho-Metalations and C–H ­Activations of Chiral Ferrocenes

AbstractChiral ferrocene derivatives possessing a planar stereogenic unit are important as chiral catalysts and materials. The principle method to obtain 1,2-disubstituted planarly chiral ferrocenes is base-mediated ortho-metalation performed on a chiral ferrocene derivative, typically using organolithium bases. A multitude of chiral ligands and other useful compounds have been synthesized by using this methodology. Newer methodologies employing transition-metal-catalyzed C–H bond activation strategies complement ortho-metalation methods and affords access to different types of planar chiral ferrocene derivatives.1 Introduction2 Base-Mediated ortho-Deprotonations3 Diastereoselective C–H Activations4 Examples of Enantioselective C–H Activations5 Conclusions

Ionic Chiral Ferrocene Doped Cholesteric Liquid Crystal with Electronically Tunable Reflective Bandwidth performance.

Cholesteric liquid crystals (CLC) were widely used in optical devices as one-dimensional photonic crystals. However, their reflective bands cannot be adjusted, which limits their wide application in many fields. In this paper, a series of ionic chiral ferrocene derivatives (CD-Fc+) as dopants were designed and prepared, and their doping into negative liquid crystal matrix was investigated to develop cholesteric response liquid crystal composites with electrically tunable reflective bands. The effects of electric field frequency, voltage, retention time of voltage and molecular structure on the broadening of reflection bandwidth were investigated in detail.

Recent advances in the synthesis of ferrocene derivatives via 3d transition metal-catalyzed C-H functionalization.

In recent years, transition-metal-catalyzed C-H functionalization has gradually developed into a powerful tool for the synthesis of ferrocenes in an atom- and step-economic fashion. However, despite significant achievements, the vast majority of these C-H functionalizations required precious 4d or 5d transition metal catalysts. The use of inexpensive and sustainable 3d metals in the C-H functionalization of ferrocenes remains challenging, especially the development of asymmetric versions. Herein, we summarize the remarkable recent progress in the synthesis of ferrocenes by 3d transition metal-catalyzed C-H activation until December 2021.

Helically aligned fused carbon hollow nanospheres with chiral discrimination ability.

While the functions of carbon materials with precisely controlled nanostructures have been reported in many studies, their chiral discriminating abilities have not been reported yet. Herein, chiral discrimination is achieved using helical carbon materials devoid of chiral attachments. A Fe3O4 nanoparticle template with ethyl cellulose (carbon source) is self-assembled on dispersed multiwalled carbon nanotubes (MWCNTs) fixed in a lamellar structure, with helical nanoparticle alignment induced by the addition of a binaphthyl derivative. Carbonization followed by template removal produces helically aligned fused carbon hollow nanospheres (CHNSs) with no chiral molecules left. Helicity is confirmed using vacuum-ultraviolet circular dichroism spectroscopy. Chiral discrimination, as revealed by the electrochemical reactions of binaphthol and a chiral ferrocene derivative in aqueous and nonaqueous electrolytes, respectively, is attributable to the chiral space formed between the CHNS and MWCNT surfaces.

Structures and Synthetic Strategies of Chiral Oxazolinyl Ferrocene Derivatives

Structures and Synthetic Strategies of Chiral Oxazolinyl Ferrocene Derivatives

1,2-Disubstituted Planar Chiral Ferrocene Derivatives from Sulfonamide-Directed ortho-Lithiation: Synthesis, Absolute Configuration, and Chiroptical Properties

A straightforward approach to the synthesis of a series of 1,2-disubstituted planar chiral ferrocenes was achieved using the ortho-directed lithiation of chiral ferrocenesulfonamides followed by a ...

Conformationally rigid chiral ferrocene derivative: Synthesis, resolution and stereochemical assignment

A conformationally rigid chiral molecule LB-I with Lewis basic site has been designed and synthesized in racemic form from ferrocene via Lewis acid mediated diastereoselective cyclization of hydroxy lactam. Both isomers were successfully obtained in enantiomerically pure form through classical resolution using dibenzoyl-d-tartaric acid as the chiral resolving agent in acetone. The nature of the diastereomeric salt formed in the resolution process was investigated by single crystal X-ray crystallographic studies. The absolute configuration of (+)-LB-I was unambiguously assigned as (S,Rp) by single crystal analysis of the salt I obtained from precipitate fraction containing (+)-LB-I and dibenzoyl-d-tartaric acid.

Organometallic Nucleoside Analogues: Effect of Hydroxyalkyl Linker Length on Cancer Cell Line Toxicity

A new series of chiral ferrocene derivatives containing both a hydroxyalkyl group and a thyminyl group on one cyclopentadienyl ring have been synthesised to probe structure–activity relationships in cancer cell line cytotoxicities. The stereoisomers of enantiomeric pairs of these so‐called ferronucleosides have been studied and characterised by a combination of chiral analytical HPLC and single‐crystal X‐ray diffraction. Biological activity studies revealed that changing the length of the hydroxyalkyl group had marked effects on IC50 values, with compounds having shorter arms that more closely resemble endogenous nucleosides exhibiting lower cytotoxicities. The lipophilicities and electrochemical properties of this compound series have been studied to rationalise these trends and indicate future directions of study.

Structures and antitumor activities of planar chiral cyclopalladated ferrocene derivatives

Bis(μ-acetato)-bridged planar chiral cyclopalladated products have been obtained by asymmetric cyclopalladation of the corresponding chiral ferrocenylimines with palladium(II) acetate and sodium acetate in methanol at room temperature. Two diastereomers were isolated in enantiomerically pure form and their absolute configurations have been determined by single-crystal X-ray analysis. It was found that enantiomerically pure cyclopalladated ferrocene displayed the excellent inhibition to two human breast carcinoma cell lines, MDA-MB-231 and MDA-MB-468 and could have good application prospect in pharmaceutical use.

ChemInform Abstract: Ferrocene Phosphane‐Heteroatom/Carbon Bidentate Ligands in Asymmetric Catalysis

AbstractReview: 208 refs.

Recent Advances in Transition-Metal-Catalyzed Enantioselective Syntheses of Planar Chiral Ferrocenes

Planar chiral ferrocene derivatives have been proved to be effective ligands and catalysts in asymmetric catalysis. The study toward enantioselective synthesis of planar chiral ferrocenes became one of the high hot spots. In this paper, the recent advance in transition-metal-catalyzed menthods for the syntheses of planar chiral ferrocenes is reviewed.

Asymmetric synthesis of planar chiral ferrocenes by enantioselective intramolecular C-H arylation of N-(2-haloaryl)ferrocenecarboxamides.

The palladium-catalyzed intramolecular C-H arylation reaction of N-(2-bromoaryl)ferrocenecarboxamides furnishes planar chiral ferrocene derivatives. TADDOL-derived phosphoramide ligands induce enantioselectivities ranging from 91:9 to 98:2 er.

Organometallic nucleoside analogues with ferrocenyl linker groups: synthesis and cancer cell line studies.

Examples of organometallic compounds as nucleoside analogues are rare within the field of medicinal bioorganometallic chemistry. We report on the synthesis and properties of two chiral ferrocene derivatives containing a nucleobase and a hydroxyalkyl group. These so-called ferronucleosides show promising anticancer activity, with cytostatic studies on five different cancer cell lines indicating that both functional groups are required for optimal activity.

Ferrocene phosphane-heteroatom/carbon bidentate ligands in asymmetric catalysis.

Chiral ferrocene derivatives belong to privileged ligand classes for asymmetric transition metal catalysed reactions. Hetero-bidentate phosphane ligands are hybrid ligands, which combine the properties of phosphorus with those of other donor atoms. This feature creates further asymmetry around the metal centre, which may be helpful for increasing the stereoinduction. Therefore, hetero-bidentate ligands are useful alternatives to homo-bidentate ligands. Ligands featuring phosphorus and nitrogen or sulphur are quite common. From among ferrocene catalysts, ferrocenyl amino phosphanes and phosphane oxazolines serve as excellent examples. Fesulphos and ThioClickFerrophos are notable P,S-ligand examples. On the other hand, combinations of phosphorus with oxygen or carbon are only beginning to show their potential in asymmetric catalysis. Another useful feature in ligands of this type is the markedly different coordination properties of donor atoms, resulting in interesting opportunities for catalysis. Ferrocenyl MOP-analogues or a fascinating combination of phosphane and secondary phosphane-oxide would represent this ligand class. The last section of the review focuses on phosphanes combined with carbon-based donor atoms that are phosphane-alkene and phosphane-carbene ligands. This review focuses on the applications of these hetero-bidentate ferrocene ligands in asymmetric catalysis with a special emphasis on the most recent and influential literature reports.

Colorimetric enantioselective recognition of chiral secondary alcohols via hydrogen bonding to a chiral metallocene containing chemosensor

An operationally simple colorimetric method for enantioselective detection of chiral secondary alcohols via hydrogen bonding interactions using a chiral ferrocene derivative is reported.

Non-Enzymatic Dynamic Kinetic Resolution of Secondary Aryl Alcohols: Planar Chiral Ferrocene and Ruthenium Catalysts in Cooperation

"Ruth" helps iron! A novel method for the non-enzymatic dynamic kinetic resolution (DKR) of secondary aryl alcohols by the use of the planar chiral ferrocene derivative (+)-1 in combination with the ruthenium racemization catalyst 2 yields acetylated alcohols in high enantioselectivity and yield. This development opens opportunities for new developments in the field of non-enzymatic dynamic kinetic resolution.

A Ferrocenyl-DHIPOH/Cu(OAc)2 Complex for Diastereo- and Enantioselective Catalysis of the 1,4-Addition of Glycine Derivatives to Alkylidene Malonates

A planar chiral ferrocene derivative Fc-DHIPOH served as an excellent N,O- chiral ligand for asymmetric copper catalyzed 1,4-addition of glycine derivatives to alkylidene malonates. The corresponding 1,4-adducts were obtained in high yields with excellent enantioselectivities up to 95% ee.

Diastereoselective ortho-lithiation of [5]ferrocenophanes

Planarly chiral ferrocene derivatives with bridged cyclopentadienyl rings are interesting ligands in asymmetric catalysis. A planar stereogenic unit is conveniently introduced by diastereoselective ortho-lithiation. The directed lithiation of several [5]ferrocenophane derivatives followed by quenching with chlorodiphenylphosphane led to planarly chiral ligands. The sense of diastereoselection was studied by computational methods. Absolute configuration of methoxy phosphane was determined by single crystal X-ray diffraction study.

En Route to New Chiral Ferrocene Derivatives: Dead Ends, Detours, and Avenues

The enantioselective synthesis of β-amino-β-ferrocenyl alcohols, a new class of chiral ferrocene derivatives suitable for the elaboration of auxiliaries and ligands for asymmetric synthesis, can be efficiently achieved by the catalytic asymmetric dihydroxylation of 1-ferrocenylalkenes, followed by the regio- and stereoselective substitution of the hydroxy group adjacent to the ferrocene moiety by nitrogen nucleophiles. En route to these compounds, several previously unknown metallocene derivatives such as α-ferrocenyl epoxides, interannularly cyclopalladated ferrocenyloxazolines, and α-amino-α-ferrocenyl acids have been obtained. The first examples of an organocatalytic approach to the enantioselective synthesis of chiral ferrocenes are also presented.