Improved Ruthenium Catalysts for Z-Selective Olefin Metathesis

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• 作者：Benjamin K. Keitz ; Koji Endo ; Paresma R. Patel ; Myles B. Herbert ; Robert H. Grubbs
• 刊名：The Journal of the American Chemical Society
• 出版年：2012
• 出版时间：January 11, 2012
• 年：2012
• 卷：134
• 期：1
• 页码：693-699
• 全文大小：345K
• 年卷期：v.134,no.1(January 11, 2012)
• ISSN：1520-5126

文摘

Several new C鈥揌-activated ruthenium catalysts for Z-selective olefin metathesis have been synthesized. Both the carboxylate ligand and the aryl group of the N-heterocyclic carbene have been altered and the resulting catalysts evaluated using a range of metathesis reactions. Substitution of bidentate with monodentate X-type ligands led to a severe attenuation of metathesis activity and selectivity, while minor differences were observed between bidentate ligands within the same family (e.g., carboxylates). The use of nitrato-type ligands in place of carboxylates afforded a significant improvement in metathesis activity and selectivity. With these catalysts, turnover numbers approaching 1000 were possible for a variety of cross-metathesis reactions, including the synthesis of industrially relevant products.