Retracing the evolution of monometallic ruthenium–arenecatalysts for C–C bond formation

Abstract

Preformed or in situ generated monometallic ruthenium–arene complexes with the generic formula RuX₂(arene)(L) (L = phosphine or N-heterocyclic carbene) are versatile and efficient catalyst precursors for olefin metathesis and atom transfer radical reactions. Their synthesis is usually accomplished using simple and straightforward experimental procedures starting from the [RuCl₂(p-cymene)]₂ dimer. This article retraces their evolution over the past 20 years and highlights similarities and differences with the parallel development of well-defined RuX₂(CHR)(L¹)(L²) ruthenium–alkylidene catalysts.