Chelating ligand precursors for the preparation of olefin methathesis catalysts are disclosed. The resulting catalysts are air stable monomeric species capable of promoting various methathesis reactions efficiently, which can be recovered from the reaction mixture and reused. Internal olefin compounds, specifically beta-substituted styrenes, are used as ligand precursors. Compared to terminal olefin compounds such as unsubstituted styrenes, the beta-substituted styrenes are easier and less costly to prepare, and more stable since they are less prone to spontaneous polymerization. Methods of preparing chelating-carbene methathesis catalysts without the use of CuCl are disclosed. This eliminates the need for CuCl by replacing it with organic acids, mineral acids, mild oxidants or even water, resulting in high yields of Hoveyda-type methathesis catalysts. The invention provides an efficient method for preparing chelating-carbene metathesis catalysts by reacting a suitable ruthenium complex in high concentrations of the ligand precursors followed by crystallization from an organic solvent.
用于制备烯烃
甲硫醇催化剂的螯合
配体前体已被披露。所得的催化剂是空气稳定的单体物种,能够有效促进各种
甲硫醇反应,并且可以从反应混合物中回收并重复使用。内部烯烃化合物,特别是β-取代
苯乙烯,被用作
配体前体。与未取代
苯乙烯等末端烯烃化合物相比,β-取代
苯乙烯更容易、成本更低,并且更稳定,因为它们不太容易自发聚合。披露了一种无需使用CuCl制备螯合-卡宾
甲硫醇催化剂的方法。通过用有机酸、矿酸、温和氧化剂甚至
水替换CuCl,从而消除了对CuCl的需求,从而得到高产率的Hoveyda型
甲硫醇催化剂。该发明提供了一种有效的方法,通过在高浓度的
配体前体中反应适当的
钌配合物,然后从有机溶剂中结晶,制备螯合-卡宾
甲硫醇催化剂。