Related Experiment Video
Updated: Jun 24, 2026

Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene
Published on: March 20, 2017
Synthesis, properties and formation of (RCp)Co- and (RCp)Rh-stabilized[4.8]3cyclacene derivatives
Stefan C Kornmayer1, Björn Hellbach, Frank Rominger
1Organisch-Chemisches Institut, Universität Heidelberg, Im Neuenheimer Feld 270, 69120 Heidelberg, Germany.
Abstract:
Metal-stabilized belts: A torus, 3, consisting of three four- and three eight-membered conjugated rings and stabilized by (RCp)Co- and (RCp)Rh- units, was generated by irradiation of [(RCp)Co(CO)(2)] and [(RCp)Rh(C(2)H(4))(2)], respectively, and 1.Eleven metal stabilized [4.8](3)cyclacene derivatives were synthesized. The substances were prepared in one-pot reactions by irradiation of a solution of 5,6,11,12-tetradehydro-dibenzo[a,e]cyclooctatetraene and the corresponding cobalt reagents or rhodium compounds. The resulting cyclacene derivatives reveal D(3h) symmetry in solution. In the solid state the hoop shaped systems crystallize in layers, which are intercalated with solvent layers. To unravel the mechanism of the one-pot reaction we isolated an intermediate, which shows almost planar cyclooctatetraene rings.
Related Concept Videos
Thermal and Photochemical Electrocyclic Reactions: Overview
[3,3] Sigmatropic Rearrangement of 1,5-Dienes: Cope Rearrangement
Woodward–Hoffmann Selection Rules and Microscopic Reversibility
Cycloaddition Reactions: Overview
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.
Aromatic Hydrocarbon Cations: Structural Overview
Removing one hydrogen from the intervening CH2 group with both...
![Solid-phase Synthesis of [4.4] Spirocyclic Oximes](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F58508.jpg&w=3840&q=50)
