DFT-guided Development of New Hemilabile (P^N) Ligands for Gold-(I/III) RedOx Catalysis : Application to the Thiotosylation of Aryl Iodides

Ligand-enabled oxidative addition of Csp2-X bonds to Au(I) centers has recently appeared as a valuable strategy for the development of catalytic RedOx processes. Several cross-coupling reactions that were previously considered difficult to achieve were reported lately, thus expanding the synthetic potential of gold(I) complexes beyond the traditional nucleophilic functionalization of pi-systems. MeDalPhos has played an important role in this development and, despite several studies on alternative structures, remains so far, the only general ligand for such process. We report herein the discovery and the DFT-guided structural optimization of a new family of hemilabile (P^N) ligands that can promote oxidative addition of aryl iodides to gold(I). These flexible ligands, which possess a common 2-methylamino heteroaromatic N-donor motif, are structurally and electronically tunable, beyond being easily accessible and affordable. The corresponding Au(I) complexes were shown to outperform the reactivity of (MeDalPhos)Au(I) in a series of alkoxy- and amidoarylation of alkenes. Their synthetic potential and comparatively higher reactivity were further highlighted in the thiotosylation of aryl iodides, a challenging unreported C-S cross-coupling reaction that could not be achieved under classical Pd(0/II) catalysis and that allows a general and divergent access to aryl sulfur derivatives.