Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Reduction of Alkenes: Asymmetric Catalytic Hydrogenation02:17

Reduction of Alkenes: Asymmetric Catalytic Hydrogenation

Catalytic hydrogenation of alkenes is a transition-metal catalyzed reduction of the double bond using molecular hydrogen to give alkanes. The mode of hydrogen addition follows syn stereochemistry.
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
Prochirality02:05

Prochirality

The concept of prochirality leads to the nomenclature of the individual faces of a molecule and plays a crucial role in the enantioselective reaction. It is a concept where two or more achiral molecules react to produce chiral products. A typical process is the reaction of an achiral ketone to generate a chiral alcohol. Here, the achiral reactant reacts with an achiral reducing agent, sodium borohydride, to generate an equimolar mixture of the chiral enantiomers of the product. For example, an...
Chirality at Nitrogen, Phosphorus, and Sulfur02:30

Chirality at Nitrogen, Phosphorus, and Sulfur

Chirality is most prevalent in carbon-based tetrahedral compounds, but this important facet of molecular symmetry extends to sp3-hybridized nitrogen, phosphorus and sulfur centers, including trivalent molecules with lone pairs. Here, the lone pair behaves as a functional group in addition to the other three substituents to form an analogous tetrahedral center that can be chiral.
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration02:34

Regioselectivity and Stereochemistry of Acid-Catalyzed Hydration

The rate of acid-catalyzed hydration of alkenes depends on the alkene's structure, as the presence of alkyl substituents at the double bond can significantly influence the rate.
Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation02:24

Reduction of Alkynes to cis-Alkenes: Catalytic Hydrogenation

Introduction
Like alkenes, alkynes can be reduced to alkanes in the presence of transition metal catalysts such as Pt, Pd, or Ni. The reaction involves two sequential syn additions of hydrogen via a cis-alkene intermediate.
SN2 Reaction: Stereochemistry02:23

SN2 Reaction: Stereochemistry

In an SN2 reaction, the nucleophilic attack on the substrate and departure of the leaving group occurs simultaneously through a transition state. As the nucleophile approaches the substrate from the back-side, the configuration of the substrate carbon changes from tetrahedral to trigonal bipyramidal and then back to tetrahedral, leading to an inversion in the configuration of the product.
If the substrate is an achiral molecule at the α-carbon, the inversion of configuration is not observed.

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Candida glabrata YPK2 is a multidrug susceptibility locus.

Genetics·2026
Same author

Imidazol-2-ylidene-Based NCCN Ligands for Chiral-at-Iron Catalysis.

Organometallics·2026
Same author

Nucleation of α-pinene oxidation products with sulfuric acid.

Environmental science: atmospheres·2026
Same author

Asymmetric Iron-Catalyzed Vicinal C(sp<sup>3</sup>)─H Diamination of Carboxylic Acids.

Angewandte Chemie (International ed. in English)·2026
Same author

Microbial Electrosynthesis Reshapes Energy Metabolism and Physiology in Clostridium ljungdahlii.

Microbial biotechnology·2026
Same author

<i>Candida glabrata YPK2</i> is a multidrug susceptibility locus.

bioRxiv : the preprint server for biology·2026

Related Experiment Video

Updated: Jul 14, 2026

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of &#945;-Imino &#947;-Lactones and Alkylidene Pyrazolones
10:17

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones

Published on: February 7, 2019

Chiral Pyrazolinylidene Complexes for Asymmetric Catalysis.

Felix Möller1, Nemrud Demirel1, Thomas Krüger1

  • 1Fachbereich Chemie, Philipps-Universität Marburg, Marburg, Germany.

Chemistry (Weinheim an Der Bergstrasse, Germany)
|July 12, 2026
PubMed
Summary

Researchers developed the first chiral pyrazolinylidene transition metal complex for asymmetric catalysis. This novel ruthenium catalyst enables efficient enantioselective synthesis of complex molecules with quaternary stereocenters.

Keywords:
N‐heterocyclic carbenesasymmetric catalysisaziridinationnitrenoidruthenium

More Related Videos

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions
19:58

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Published on: July 30, 2017

Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks (MOFs)
08:25

Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks (MOFs)

Published on: January 17, 2020

Related Experiment Videos

Last Updated: Jul 14, 2026

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of &#945;-Imino &#947;-Lactones and Alkylidene Pyrazolones
10:17

Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones

Published on: February 7, 2019

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions
19:58

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Published on: July 30, 2017

Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks (MOFs)
08:25

Development of Heterogeneous Enantioselective Catalysts using Chiral Metal-Organic Frameworks (MOFs)

Published on: January 17, 2020

Area of Science:

  • Organometallic Chemistry
  • Asymmetric Catalysis
  • Ligand Design

Background:

  • N-heterocyclic carbenes (NHCs) are crucial ligands in homogeneous catalysis due to their strong sigma-donating properties.
  • Pyrazolinylidenes, a subclass of NHCs, are relatively unexplored in catalysis.
  • Developing new chiral ligands is essential for advancing asymmetric synthesis.

Purpose of the Study:

  • To develop the first chiral pyrazolinylidene transition metal complex for asymmetric catalysis.
  • To synthesize and characterize novel chiral ruthenium(II) complexes featuring pyrazolin-5-ylidene ligands.
  • To evaluate the catalytic performance of these complexes in enantioselective transformations.

Main Methods:

  • Modular synthesis of N-(2-pyridyl)-substituted pyrazolin-5-ylidene ligands.
  • Preparation and characterization of chiral-at-ruthenium(II) complexes.
  • Spectroscopic analysis (e.g., NMR, IR) to determine electronic properties and structure.
  • Testing the catalyst in enantioselective intramolecular aziridination reactions.

Main Results:

  • Successful development of chiral-at-ruthenium catalysts with bidentate pyrazolin-5-ylidene ligands.
  • Systematic ligand modification allowed access to air-stable ruthenium(II) complexes.
  • Spectroscopic data revealed enhanced sigma-donor strength and a pronounced transeffect compared to related carbenes.
  • The catalyst achieved up to 95% yield and 98% enantiomeric excess in the asymmetric aziridination of alkene-tethered N-benzoyloxyurea.

Conclusions:

  • Pyrazolin-5-ylidenes are effective ligands for chiral transition metal catalysis.
  • The developed ruthenium catalyst scaffold is robust and applicable to other asymmetric reactions.
  • This work expands the scope of NHC ligands in asymmetric catalysis, particularly with pyrazolinylidene systems.