Direct Detection of Pt(IV) Phenyl Complexes upon Intermolecular Oxidative Addition of Aryl Halides and Selective Csp3–I versus Csp2–Csp3 and Csp3–Csp3 Bonds Reductive Elimination from N-Heterocyclic Carbene Pt(IV) Phenyl Complexes

Abstract

Reaction of a chelating N-heterocyclic carbene Pt(II) dimethyl complex with phenyl iodide and excess KI results in the direct detection of a Pt(IV) phenyl intermediate by ¹H NMR spectroscopy. This finding provides experimental evidence that the reaction between Pt(II) dimethyl complexes and aryl halides proceeds via a concerted oxidative addition (OA) mechanism. Additionally, we report on the selective reductive elimination (RE) of Csp³–I vs Csp²–Csp³ and Csp³–Csp³ bonds. Lastly, OA, different RE pathways, and reactivity of different isomers were investigated by computational methods that are consistent with experimental observations. We believe that these results have important implications for the development of new Pt-catalyzed transformations.