Olefin metathesis in air using latent ruthenium catalysts: imidazole substituted amphiphilic hydrogenated ROMP polymers providing nano-sized reaction spaces in water†,Catalysis Science & Technology

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Olefin metathesis in air using latent ruthenium catalysts: imidazole substituted amphiphilic hydrogenated ROMP polymers providing nano-sized reaction spaces in water†
Catalysis Science & Technology ( IF 4.4 ) Pub Date : 2018-09-28 00:00:00 , DOI: 10.1039/c8cy01818a
Bengi Özgün Öztürk _{1,

2,

3,

4,

5} , Burcu Durmuş _{1,

2,

3,

4,

5} , Solmaz Karabulut Şehitoğlu _{1,

2,

3,

4,

5}

Affiliation

Imidazole substituted hydrogenated amphiphilic ROMP polymers were used as both surfactants and ligand precursors for olefin metathesis reactions in water. Amphiphilic ROMP polymers were synthesized using a two-step procedure. Firstly, dimethyl-5-norbornene-2,3-dicarboxylate was polymerized using ring-opening metathesis polymerization (ROMP)/cross-metathesis (CM) in the presence of allyl-PEG5000 methyl ether and a Grubbs 3rd generation (G3) catalyst. Secondly, a one-pot hydrogenation/aminolysis protocol was used for the post-polymerization modification of PEG end-capped polynorbornene derivatives. Hydrogenation reactions were carried out using residual G3 in the presence of formic acid/sodium formate in THF at 70 °C. The aminolysis reaction was carried out without isolation of the hydrogenated polymer, using triazabicyclodecene (TBD) and 1-(3-aminopropyl)-imidazole, forming imidazole substituted hydrogenated amphiphilic ROMP polymers (mod-Amph1) in an efficient manner. G1-mod-Amph1 formed micelle structures in water with an average particle size of 85.95 (±35) nm as determined by transmission electron microscopy (TEM) and dynamic light scattering (DLS) analysis. The diffusion of Grubbs 1st generation (G1) catalyst into the micelle structure has led to the formation of nano-sized catalysts which exhibited a latent characteristic. The diffusion of hydrophobic olefinic substrates into the nano-reaction spaces, followed by activation of the catalyst with HCl led to a very efficient catalytic system for ring-closing metathesis reactions. RCM reactions of various hydrophobic dienes can run in non-degassed water under an air atmosphere. The catalyst system exhibits similar performance under an air atmosphere even in tap water, reaching a conversion value of 90% for RCM of diethyl diallylmalonate with a catalytic loading of 1% Ru.

中文翻译：

使用潜在的钌催化剂在空气中进行烯烃复分解：咪唑取代的两亲氢化ROMP聚合物可在水中提供纳米级的反应空间†

咪唑取代的氢化两亲ROMP聚合物既用作表面活性剂，也用作配体前体，用于水中的烯烃复分解反应。使用两步法合成两亲ROMP聚合物。首先，在烯丙基-PEG5000甲基醚和Grubbs第三代（G3）催化剂存在下，使用开环易位聚合（ROMP）/交叉复分解（CM），将5-降冰片烯-2，3-二羧酸二甲酯聚合。其次，将一锅加氢/氨解方案用于PEG封端的聚降冰片烯衍生物的聚合后修饰。在甲酸/甲酸钠在THF中于70°C存在的条件下，使用残留的G3进行氢化反应。在不分离氢化聚合物的情况下进行氨解反应，使用三氮杂双环癸烯（TBD）和1-（3-氨基丙基）-咪唑，以有效的方式形成咪唑取代的氢化两亲ROMP聚合物（mod-Amph1）。通过透射电子显微镜（TEM）和动态光散射（DLS）分析确定，G1-mod-Amph1在水中形成的胶束结构的平均粒径为85.95（±35）nm。格拉布斯第一代（G1）催化剂向胶束结构的扩散导致形成了具有潜在特性的纳米级催化剂。疏水性烯烃底物扩散到纳米反应空间中，然后用HCl活化催化剂，导致了非常有效的催化系统，用于闭环复分解反应。各种疏水性二烯的RCM反应可在空气气氛下的非脱气水中进行。

更新日期：2018-09-28

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