Synthesis of Methylidene Complexes that Contain a 2,6-Dimesitylphenylimido Ligand and Ethenolysis of 2,3-Dicarbomethoxynorbornadiene

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• 作者：Laura C. H. Gerber ; Richard R. Schrock
• 刊名：Organometallics
• 出版年：2013
• 出版时间：October 14, 2013
• 年：2013
• 卷：32
• 期：19
• 页码：5573-5580
• 全文大小：383K
• 年卷期：v.32,no.19(October 14, 2013)
• ISSN：1520-6041

文摘

Monoalkoxide pyrrolide (MAP) complexes that contain a 2,6-dimesitylphenylimido (NAr*) ligand react with ethylene to yield unsubstituted metallacyclobutanes that are in equilibrium with methylidene complexes, W(NAr*)(CH₂)(Me₂Pyr)(OR) (R = t-Bu, OCMe(CF₃)₂, SiPh₃, or 2,6-Me₂C₆H₃). Polymerization of 2,3-dicarbomethoxynorbornadiene (DCMNBD) with M鈺怌HCMe₂Ph (M = Mo or W) initiators is slow as a consequence of a slow propagation step. However, W(NAr*)(CH₂)(Me₂Pyr)(OR) (R = SiPh₃ or 2,6-dimethylphenyl) complexes react readily with 1 equiv of DCMNBD to give a monoinsertion product. The facile reaction between the monoinsertion product and ethylene then allows these complexes to be catalyts for the ring-opening cross-metathesis (ethenolysis) of DCMNBD and DCMNBE (2,3-dicarbomethoxynorbornene) with minimal formation of polymer.