Synthesis and Reactivity of Ruthenium Phosphite Indenylidene Complexes
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- 作者：Xavier Bantreil ; Albert Poater ; C茅sar A. Urbina-Blanco ; Yannick D. Bidal ; Laura Falivene ; Rebecca A. M. Randall ; Luigi Cavallo ; Alexandra M. Z. Slawin ; Catherine S. J. Cazin
- 刊名：Organometallics
- 出版年：2012
- 出版时间：November 12, 2012
- 年：2012
- 卷：31
- 期：21
- 页码：7415-7426
- 全文大小：655K
- 年卷期：v.31,no.21(November 12, 2012)
- ISSN：1520-6041
文摘
The synthesis of the four olefin metathesis precatalysts Caz-1a鈥?b>d, featuring the NHC ligand N,N鈥?/i>-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene (SIMes) and four different phosphites (P(OiPr)3, P(OPh)3, P(OEt)3, and P(OMe)3), is reported. The complexes are readily synthesized from commercially available [RuCl2(3-phenylinden-1-ylidene)(pyridine)(SIMes)] (Ind-III) 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, cis-Caz-1a, featuring a P(OiPr)3 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.