Air-stable, dinuclear and tetranuclear σ,π-acetylide gold(I) complexes and their catalytic implications.

Two for one gold: Factors governing the formation of isolable digold(I) σ,π-acetylide complexes are given (see scheme), indicating the general tendency of phosphine-Au(I) precatalysts to form this type of complexes, which are involved as reaction intermediates in gold(I)-catalyzed reactions. Mechanistic insights into the intermolecular hydroamination of aniline and terminal alkynes catalyzed by gold(I) have shown the role of a fluxional, cationic σ,π-digold alkynide complex as one of the intermediates in the formation of imines.