Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, 8093, Zurich, Switzerland.
Institute of Polymer Chemistry, University of Stuttgart, Pfaffenwaldring 55, 70569, Stuttgart, Germany.
Angew Chem Int Ed Engl. 2016 Mar 18;55(13):4300-2. doi: 10.1002/anie.201510678. Epub 2016 Mar 1.
Designing supported alkene metathesis catalysts with high activity and stability is still a challenge, despite significant advances in the last years. Described herein is the combination of strong σ-donating N-heterocyclic carbene ligands with weak σ-donating surface silanolates and cationic tungsten sites leading to highly active and stable alkene metathesis catalysts. These well-defined silica-supported catalysts, [(≡SiO)W(=O)(=CHCMe2 Ph)(IMes)(OTf)] and [(≡SiO)W(=O)(=CHCMe2 Ph)(IMes)(+) ][B(Ar(F) )4 (-) ] [IMes=1,3-bis(2,4,6-trimethylphenyl)-imidazol-2-ylidene, B(Ar(F) )4 =B(3,5-(CF3 )2 C6 H3 )4 ] catalyze alkene metathesis, and the cationic species display unprecedented activity for a broad range of substrates, especially for terminal olefins with turnover numbers above 1.2 million for propene.
尽管近年来在这方面取得了重大进展，但设计具有高活性和稳定性的支持型烯烃复分解催化剂仍然是一个挑战。本文描述了强σ-给体 N-杂环卡宾配体与弱σ-给体表面硅醇盐和阳离子钨位点的结合，从而得到高活性和稳定的烯烃复分解催化剂。这些结构明确的负载型硅催化剂，[(≡SiO)W(=O)(=CHCMe2 Ph)(IMes)(OTf)] 和 [(≡SiO)W(=O)(=CHCMe2 Ph)(IMes)(+) ][B(Ar(F) )4 (-) ] [IMes=1,3-双(2,4,6-三甲基苯基)-咪唑-2-亚基，B(Ar(F) )4 =B(3,5-(CF3 )2 C6 H3 )4 ]，可催化烯烃复分解反应，而阳离子物种对广泛的底物表现出前所未有的活性，特别是对于末端烯烃，其丙烯的周转数超过 120 万。
