Invited Lecture – Cristina Nevado

Gold-catalyzed oxidative cross-couplings have bloomed in the past few years postulating gold(III) fluorides as productive reactive intermediates. However, experimental support for these species is to-date scarce due to their labile nature, and thus the reactivity of Au-F bonds remains largely unexplored. In order to address these challenges, novel 3,5-disubstituted phenylpyridine based ligands have been developed. Interestingly, these (N^C^C)Au^III-F complexes reacted with different terminal alkynes under mild reaction conditions resulting in the formation of gold-alkynyl species which exhibit striking luminescent properties compared to their analogous (C^N^C)Au^III complexes. Further, these newly stabilized gold(III) fluorides interact with boronic acids. Aryl boron reagents have been typically used as reaction partners in gold oxidative couplings with Selectfluor as stoichiometric oxidant. Au^III-F species have been invoked as the key partners of boron species towards the formation of new C-C bonds. However, the nature of the interaction Au^III-F/B is still unclear. Taking advantage of fine-tuned C^N type ligands, we were able to access monocyclometalated (C^N) Au^IIII(R)F (R = F, alkyl, aryl) complexes in monomeric form that were used to probe the interaction Au^III-F with aryl boronic acids. We showed that a direct transmetalation precedes reductive elimination to produce the coupling product thus ruling out a bimolecular reductive elimination pathway.