10.1021/om300703p.s001
Xavier Bantreil
Xavier
Bantreil
Albert Poater
Albert
Poater
César
A. Urbina-Blanco
César
A.
Urbina-Blanco
Yannick D. Bidal
Yannick D.
Bidal
Laura Falivene
Laura
Falivene
Rebecca A. M. Randall
Rebecca
A. M. Randall
Luigi Cavallo
Luigi
Cavallo
Alexandra M. Z. Slawin
Alexandra
M. Z. Slawin
Catherine S. J. Cazin
Catherine
S. J. Cazin
Synthesis and Reactivity
of Ruthenium Phosphite Indenylidene
Complexes
American Chemical Society
2012
metathesi
catalyst loadings
Ruthenium Phosphite Indenylidene ComplexesThe synthesis
precatalyst
NHC ligands
cis complexes
cis configuration
NMR experiments
trans counterparts
phosphite
2012-11-12 00:00:00
Journal contribution
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.