Related Experiment Video
Updated: Oct 22, 2025

Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene
Published on: March 20, 2017
Take a "Snapshot" of New Syntheses, Reactions, and Characterizations from Unusual Unsaturated Ring Strained Group 4
1Leibniz Institute for Catalysis, University of Rostock, Albert-Einstein-Str. 29 A, 18059, Rostock, Germany.
Abstract:
Recently published syntheses, reactions and characterizations of unusual unsaturated ring strained Group 4 metallocene metallacycles like metalla-cyclocumulenes, -cycloallenes and -cycloalkynes with different ring size are updated for the last three years. There exist for some of these metallacycles, depending on the ring size, 7-, 5- and 4-membered compounds. The new results for these metallacycles are summarized here and considered in addition to the former published results. Additionally, several compounds of this type were now characterized by new reactions. For a better understanding of these compounds, some spectroscopical methods as well as theoretical calculations were published. Despite of these all-C-metallacycles, only in some cases the syntheses and reactions for the corresponding hetero-metallacycles were published too. Examples for these metallaheterocyclic compounds will not be considered in this article. All these unusual ring strained compounds have a great potential for a lot of interesting synthetic applications in the future. Additionally, they are very interesting from the theoretical point of view.
More Related Videos
Related Concept Videos
Cycloaddition Reactions: Overview
Pericyclic Reactions: Introduction
Pericyclic reactions can be classified into three categories: electrocyclic reactions, cycloaddition reactions, and sigmatropic rearrangements. Electrocyclic reactions and sigmatropic...
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Thermal and Photochemical Electrocyclic Reactions: Overview
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry

