Olefin Hydroarylation Catalyzed by (pyridyl-indolate)Pt(II) Complexes: Catalytic Efficiencies and Mechanistic Aspects

A series of Pt(II) complexes of the type (N- N)PtPh(SR2) (N-N = 2,2'-pyridyl-indolate) were prepared, and their performance as catalysts for the hydroarylation of olefins was assessed. Evidence that the catalysis is homogeneous and is Pt mediated is provided by control experiments with added hindered base (2,6-di-tert-butyl-4-methylpyridine) and Hg(0). Two potential catalytic intermediates, ((t)BuPyInd)PtPh(C2H4) and ((t)BuPyInd)Pt(CH2CH2Ph)(C2H4), were synthesized, and their catalytic efficacy was explored. Additionally, decomposition and deactivation pathways, including styrene formation via beta-hydride elimination and ligand reductive demetalation, were identified.