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Updated: Aug 3, 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
Polarity matching of radical trapping: high yielding 3-exo and 4-exo cyclizations
Andreas Gansäuer1, Thorsten Lauterbach, Daniel Geich-Gimbel
1Kekulé-Institut für Organische Chemie und Biochemie der Universität Bonn, Gerhard Domagk Strasse 1, 53121 Bonn, Germany. andreas.gansaeuer@uni-bonn.de <andreas.gansaeuer@uni-bonn.de>
Abstract:
A catalyzed synthesis of cyclopropanes and cyclobutanes via radical chemistry is described. The method that generally proceeds in high yields uses epoxides as radical precursors and titanocene(III) complexes as the electron transfer catalysts (see scheme). The key to the success of the transformation is constituted by the chemoselectivity of radical reduction. Electrophilic enol radicals generated through cyclization are reduced rapidly whereas their precursors, nucleophilic alkyl radicals, remain unaffected.
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