Related Experiment Video
Updated: Jul 15, 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
Cobalt(I)-mediated preparation of polyborylated cyclohexadienes: scope, limitations, and mechanistic insight
Anaïs Geny1, David Leboeuf, Gabriel Rouquié
1Laboratoire de Chimie Organique, Université Pierre et Marie Curie, Tour 44-54, 4 place Jussieu 75252 Paris, France.
Abstract:
A series of 1,3- and 1,4-diboryl-1,3-cyclohexadienes have been prepared by intermolecular CoCp-mediated [2+2+2] cocyclizations of alkynylboronic pinacolate esters with alkenes, followed by oxidative demetallation with iron(III) chloride. The effect of substitution at the borylated alkyne on chemo- and regioselectivities has been studied, suggesting steric control. The proper choice of substituents allowed the preparation of 1,3-diborylated cyclohexadienes in a highly selective manner. Alternatively, 1,4-diborylated cyclohexadienes could be prepared from diborylated diynes. The scope of this reaction has been examined and found to include electron-poor, electron-rich, linear, and cyclic alkenes. The diborylated cyclohexadienes were submitted to single or double Suzuki-Miyaura cross-coupling reactions with haloarenes to afford polyarylated systems. The mechanism of the title reaction, including the regioselectivity of the cycloaddition steps, has been analyzed by means of DFT computations.
More Related Videos
Related Concept Videos
Cycloaddition Reactions: Overview
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Cycloaddition Reactions: MO Requirements for Thermal Activation
Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)
Thermal and Photochemical Electrocyclic Reactions: Overview
Cycloaddition Reactions: MO Requirements for Photochemical Activation

