Gold(I) Catalyzes the Intermolecular Hydroamination of Alkynes with Imines and Produces α,α′,<i>N</i>-Triarylbisenamines: Studies on Their Use As Intermediates in Synthesis

α,α′,N-Triarylbisenamines have been efficiently formed and isolated for the first time. The synthesis is based on an unprecedented gold(I)-catalyzed double intermolecular hydroamination between N-arylamines and aryl alkynes. This reaction constitutes a new example of the intriguing behavior of gold as catalyst in organic synthesis. The reactivity of these bisenamines for three different reactions, leading to potentially useful intermediates, is also shown. In particular, hindered azabicycles [3.2.0], which present excellent UVA and UVB absorption properties, are obtained by addition of triarylbisenamines to propiolates following an unexpected mechanism.