Exploring the Influence of Phosphine Ligation on the Gold-Catalyzed Hydrohydrazination of Terminal Alkynes at Room Temperature

The synthesis and/or NMR/X-ray characterization of a new series of (L)AuCl complexes is reported, featuring BippyPhos, AdJohnPhos, silyl ether based ligands including OTips-DalPhos, and PAd-DalPhos. These complexes, along with previously reported analogues featuring cataCXium-A, tBuJohnPhos, and Mor-DalPhos, were screened as precatalysts using LiB(C6F5)4·2.5Et2O as an activator in the hydrohydrazination of terminal aryl alkynes with hydrazine hydrate under unprecedentedly mild conditions (25 °C, 1 mol % Au). The precatalyst (cataCXium-A)AuCl proved to be particularly effective in such transformations, demonstrating useful scope.