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Updated: Apr 30, 2026

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
Propargyltrimethylsilanes as allene equivalents in transition metal-catalyzed [5 + 2] cycloadditions
Paul A Wender1, Fuyuhiko Inagaki, Magnus Pfaffenbach
1Department of Chemistry, Department of Chemical and Systems Biology, Stanford University , Stanford, California 94305-5080, United States.
Abstract:
Conventional allenes have not been effective π-reactive 2-carbon components in many intermolecular cycloadditions including metal-catalyzed [5 + 2] cycloadditions. We report herein that rhodium-catalyzed [5 + 2] cycloadditions of propargyltrimethylsilanes and vinylcyclopropanes provide, after in situ protodesilylation, a highly efficient route to formal allene cycloadducts. Propargyltrimethylsilanes function as safe, easily handled synthetic equivalents of gaseous allenes and hard-to-access monosubstituted allenes. In this one-flask procedure, they provide cycloadducts of what is formally addition to the more sterically encumbered allene double bond.
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