Synthesis and Reactivity of Ruthenium Phosphite Indenylidene Complexes Xavier Bantreil Albert Poater César A. Urbina-Blanco Yannick D. Bidal Laura Falivene Rebecca A. M. Randall Luigi Cavallo Alexandra M. Z. Slawin Catherine S. J. Cazin 10.1021/om300703p.s001 https://acs.figshare.com/articles/journal_contribution/Synthesis_and_Reactivity_of_Ruthenium_Phosphite_Indenylidene_Complexes/2470288 The synthesis of the four olefin metathesis precatalysts <b>Caz-1a</b>–<b>d</b>, featuring the NHC ligand <i>N</i>,<i>N′</i>-bis­(2,4,6-trimethylphenyl)­imidazolin-2-ylidene (SIMes) and four different phosphites (P­(O<sup><i>i</i></sup>Pr)<sub>3</sub>, P­(OPh)<sub>3</sub>, P­(OEt)<sub>3</sub>, and P­(OMe)<sub>3</sub>), is reported. The complexes are readily synthesized from commercially available [RuCl<sub>2</sub>(3-phenylinden-1-ylidene)­(pyridine)­(SIMes)] (<b>Ind-III</b>) in yields of up to 88%. These complexes adopt an unusual cis configuration between the phosphite and the NHC ligands. NMR experiments and computational studies confirm that the cis complexes are thermodynamically favored in comparison to their trans counterparts. In addition, the isomerization from trans to cis occurs via a mononuclear and non-dissociative mechanism. Among the four precatalysts, <i>cis</i>-<b>Caz-1a</b>, featuring a P­(O<sup><i>i</i></sup>Pr)<sub>3</sub> ligand, displays the highest activity in ring-closing metathesis and cross-metathesis transformations. Experiments at low catalyst loadings demonstrated the potential of this catalyst, allowing better conversions than with commonly used commercially available precatalysts. 2012-11-12 00:00:00 metathesi catalyst loadings Ruthenium Phosphite Indenylidene ComplexesThe synthesis precatalyst NHC ligands cis complexes cis configuration NMR experiments trans counterparts phosphite