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Updated: Sep 17, 2025

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
Reversible addition of ethene to gallium(i) monomers and dimers
Ryan J Schwamm1, Malavika A Bhide1, Gary S Nichol1
1School of Chemistry, The University of Edinburgh Joseph Black Building, David Brewster Road Edinburgh EH9 3FJ UK michael.cowley@ed.ac.uk.
Abstract:
Reversible interactions of organic substrates with transition metal compounds are a hallmark of their chemistry and its catalytic applications, but remain uncommon for low-valent p-block compounds. We report here the preparation of amidophosphine-supported gallium(i) compounds that exhibit equilibria between monomeric gallylene and dimeric digallene (Ga[double bond, length as m-dash]Ga) states. The monomer-dimer equilibrium is controlled by the steric and electronic properties of the phosphine donor in the ligand employed. Regardless of their preference for monomeric or dimeric state, reactions of the Ga(i) systems with B(C6F5)3 affords monomeric gallylene adducts, whilst reactions with ethene produce 1,2-digallacyclobutanes via formal [2 + 2] cycloadditions. These ethene additions are reversible, with the digallacyclobutanes releasing ethene upon heating or treatment with Lewis acids to regenerate the gallium(i) species.
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