Binder Joseph B, Guzei Ilia A, Raines Ronald T
Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706-1322, USA.
Adv Synth Catal. 2007 Feb 2;349(3):395-404. doi: 10.1002/adsc.200600264.
Tuning the electronic and steric environment of olefin metathesis catalysts with specialized ligands can adapt them to broader applications, including metathesis in aqueous solvents. Bidentate salicylaldimine ligands are known to stabilize ruthenium alkylidene complexes, as well as allow ring-closing metathesis in protic media. Here, we report the synthesis and characterization of exceptionally robust olefin metathesis catalysts bearing both bidentate salicylaldimine and N-heterocyclic carbene ligands, including a trimethylammonium-functionalized complex adapted for polar solvents. NMR spectroscopy and X-ray crystallographic analysis confirm the structures of the complexes. Although the N-heterocyclic carbene-salicylaldimine ligand combination limits the activity of these catalysts in nonpolar solvents, this pairing enables efficient ring-closing metathesis of both dienes and enynes in methanol and methanol-water mixtures under air.
通过使用特殊配体调节烯烃复分解催化剂的电子和空间环境，可以使其适用于更广泛的应用，包括在水性溶剂中的复分解反应。已知双齿水杨醛亚胺配体可稳定钌亚烷基配合物，并能在质子介质中进行闭环复分解反应。在此，我们报道了同时含有双齿水杨醛亚胺和N-杂环卡宾配体的异常稳定的烯烃复分解催化剂的合成与表征，其中包括一种适用于极性溶剂的三甲基铵官能化配合物。核磁共振光谱和X射线晶体学分析证实了配合物的结构。尽管N-杂环卡宾-水杨醛亚胺配体组合限制了这些催化剂在非极性溶剂中的活性，但这种配对能够在空气中使二烯烃和烯炔在甲醇和甲醇-水混合物中高效地进行闭环复分解反应。
