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Updated: Oct 22, 2025
Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
Illuminating anti-hydrozirconation: controlled geometric isomerization of an organometallic species
Theresa Hostmann1, Tomáš Neveselý1, Ryan Gilmour1
1Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster Corrensstraße 36 48149 Münster Germany ryan.gilmour@uni-muenster.de.
Abstract:
A general strategy to enable the formal anti-hydrozirconation of arylacetylenes is reported that merges cis-hydrometallation using the Schwartz Reagent (Cp2ZrHCl) with a subsequent light-mediated geometric isomerization at λ = 400 nm. Mechanistic delineation of the contra-thermodynamic isomerization step indicates that a minor reaction product functions as an efficient in situ generated photocatalyst. Coupling of the E-vinyl zirconium species with an alkyne unit generates a conjugated diene: this has been leveraged as a selective energy transfer catalyst to enable E → Z isomerization of an organometallic species. Through an Umpolung metal-halogen exchange process (Cl, Br, I), synthetically useful vinyl halides can be generated (up to Z : E = 90 : 10). This enabling platform provides a strategy to access nucleophilic and electrophilic alkene fragments in both geometric forms from simple arylacetylenes.
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