Ruthenium Olefin Metathesis Catalysts with N-Heterocyclic Carbene Ligands BearingN-Naphthyl Side Chains

A series of second-generation ruthenium-based olefin metathesis catalysts bearing N-naphthylsubstituted N-heterocyclic carbene (NHC) ligands have been prepared and fully characterized. By reaction with the appropriate NHC, these complexes are readily accessible in one synthesis step from commercially available first generation precursors [RuCl2(=CHPh)(PCy3)2] (Grubbs’ I, GI) or [RuCl2(=CH-o-iPrO-Ph)(PCy3)] (Hoveyda-Grubbs’ I, HGI) by simple exchange of one phosphine ligand with the free NHCs. Time-dependent conversions in the ring-closing metathesis (RCM) of standard substrates leading to di- as well as trisubstituted olefins have been measured for these catalysts. When benchmarked against the parent SIMes-containing Grubbs’ II precatalyst (GII), most of these new NHC structures show enhanced reactivity in RCM. From these comparative studies, valuable information was gathered that shows that the alkyl substitution on the naphthyl side chains can enhance or lower the catalytic performance depending on the bulk and the position of these alkyl groups. The behavior of the best performing precatalysts has been investigated in the RCM of a series of representative substrates, in enyne metathesis reactions as well as in cross-metathesis (CM)

Agroecological transformation for sustainable food systems : Insight on France-CGIAR research

This 26th dossier d’Agropolis is devoted to research and partnerships in agroecology. The French Commission for International Agricultural Research (CRAI) and Agropolis International, on behalf of CIRAD, INRAE and IRD and in partnership with CGIAR, has produced this new issue in the ‘Les dossiers d’Agropolis international’ series devoted to agroecology. This publication has been produced within the framework of the Action Plan signed by CGIAR and the French government on February 4th 2021 to strengthen French collaboration with CGIAR, where agroecology is highlighted as one of the three key priorities (alongside climate change, nutrition and food systems)