Flash Communication: Double Migratory Insertion in Digold(I) Acetylides

This work describes the sequential double insertion of dimethyl acetylenedicarboxylate (DMAD) into NHC-supported dinuclear gold(I) acetylides of the type NHC–Au–(C≡C)n–Au–NHC. By extending the acetylide linker in IPr–Au–C≡C–C≡C–Au–IPr (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) or using sterically reduced NHC ligands in IiPr–Au–C≡C–Au–IiPr (IiPr = 1,3-bis(isopropyl)imidazol-2-ylidene), the steric constraints that previously limited reactivity to single insertions have been overcome. These findings highlight how ligand tuning can unlock new reactivity patterns in bimetallic gold architectures.