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Updated: May 7, 2026
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Published on: June 21, 2017
Stepwise alkyne insertion in Au(i) acetylides: influence of the nuclearity
Juan Cayuela-Castillo1, Francisco J Fernández-de-Córdova1, Matthew S See2
1Instituto de Investigaciones Químicas (IIQ), Departamento de Química Inorgánica, Centro de Innovación en Química Avanzada (ORFEO-CINQA), CSIC and Universidad de Sevilla 41092 Sevilla Spain prios1@us.es.
Abstract:
The reaction between NHC-supported (NHC = N-heterocyclic carbene) gold(i) trimethylsilylacetylide complexes with NHC gold(i) hydroxide species renders different symmetrical homobimetallic Au complexes. These compounds readily undergo migratory insertion of DMAD (dimethyl acetylenedicarboxylate) at 25 °C to give the corresponding bimetallic enyne products. On the contrary, monometallic analogues require much more forcing conditions (excess of DMAD and temperature ≥110 °C) to give the same transformation. Experimental and computational studies reveal that the second metal fragment is responsible for the enhanced nucleophilicity of the reactive carbon atom of the acetylide C[triple bond, length as m-dash]C bond, which initially leads to a more favorable interaction with DMAD in the rate-determining step of an unprecedented, stepwise mechanism where the lability of the Au-C bonds plays an instrumental role. The enhanced reactivity displayed by the bimetallic species was leveraged in the insertion of other substrates such as heterocumulenes.
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