Supported Noyori-Ikariya catalysts for asymmetric transfer hydrogenations and related tandem reactions

Following the impressive rise of homogeneous ruthenium-based bifunctional catalysts in asymmetric transfer hydrogenation, Noyori-Ikariya catalysts have gradually been supported on a plethora of materials like silicas, polymers, ionic liquids or micelles for economic, environmental and societal reasons. These supported catalysts have allowed asymmetric transfer hydrogenation of carbonyl derivatives and imines with high activities and enantioselectivities. Furthermore, they have been combined with other supported organometallic or organic catalysts to perform effectively tandem reactions combining transfer hydrogenation with Sonogashira or Suzuki cross-couplings, aza-Michael reaction, alkyne hydration, lactonisation, oxysulfonylation or oxidation. This article reviews over the past 7 years the development of supported Noyori-Ikariya catalysts based on ruthenium, rhodium and iridium for asymmetric transfer hydrogenation of various CO and CN double bonds and related tandem reactions through the use of an additional supported organometallic or organic catalyst. It highlights and discusses the synthesis, reactivity and performances of these new bifunctional catalysts, as well as their recycling.