为了深入了解用于烯烃聚合的双金属催化剂的行为,合成了一系列结构相关的双核锆催化剂,其中双胺双酚盐和吡啶双酚盐配体通过刚性三芳基单元连接。蒽-9,10-二基和2,3,5,6-四甲基苯-1,4-二基用作连接基。在酚盐氧的邻位使用大的Si i Pr 3和SiPh 3取代基。伪Ç小号和Ç 2观察到双胺双酚盐配体的双核配合物存在对称异构体。通常,与单锆类似物相比,双核催化剂显示出更高的全同立构规整度,异构体之间存在一些差异。发现存在双胺胺的双酚盐二锆络合物具有中等活性(最高达1.5 kg mmol Zr –1 h –1),可在存在下将1-己烯聚合为等规富集的聚1-己烯(高达45%mmmm)。化学计量的三苯甲基或苯甲酸硼酸盐活化剂。在生产等规富集聚丙烯的过程中观察到中等活性(最高2.8 kg mmol Zr –1 h –1和最高25.4%mmmm)。先前提出的基于来自第二金属位点的远端空间效应的立构规
A Chiral Phenoxyamine Magnesium Catalyst for the Enantioselective Hydroamination/Cyclization of Aminoalkenes and Intermolecular Hydroamination of Vinyl Arenes
作者:Xiaoming Zhang、Thomas J. Emge、Kai C. Hultzsch
DOI:10.1002/anie.201105079
日期:2012.1.9
If Grignard had only known! A chiral magnesium complex catalyzes the intramolecular hydroamination/cyclization of aminoalkenes with high efficiency at temperatures as low as −20 °C and enantioselectivities as high as 93 % ee. The high activity of this system also allows the catalytic intermolecular anti-Markovnikov addition of pyrrolidine and benzylamine to vinyl arenes.
oxyl) and L3MgiPr (L3 = 4-tert-butyl-6-(triphenylsilyl)-2-[benzyl((3-(dimethylamino)propyl)amino)methyl]phenoxyl) supported by potentially tetradentate and tridentate triphenylsilyl-substituted phenoxyamine ligands have been prepared and fully characterized. The X-ray crystallographic analysis of L2MgiPr confirmed a monomeric structure in which only one of the amine side arms is bound to the four-coordinate
镁配合物L 2 Mg i Pr(L 2 = 4-叔丁基-6-(三苯基甲硅烷基)-2- [双((3-(二甲基氨基)丙基)氨基)甲基]苯氧基)和L 3 Mg i Pr( L 3=由潜在的四齿和三齿三苯基甲硅烷基取代的苯氧胺配体支撑的4-叔丁基-6-(三苯基甲硅烷基)-2- [苄基((3-(二甲氨基丙基)氨基)甲基]苯氧基)表征。对L 2 Mg i Pr的X射线晶体学分析证实了单体结构,其中只有一个胺侧臂与四配位的镁原子键合。L中自由和协调的侧臂2 Mg i Pr在25°C的溶液中进行交换过程,而苯氧基二胺配合物L 3 Mg i Pr在另一方面却没有流动性迹象。两种配合物以及L 1 Mg i Pr(L 1 = 4,6-二叔丁基-2- [双(((3-(二甲基氨基)丙基)氨基)甲基]苯氧基)都证明是有效的。氨基烯烃环化中的催化剂。L 2 Mg i Pr表现出最佳的催化活性,并且三苯基甲硅烷基取代的配
Asymmetric hydroamination catalyzed by a new chiral zirconium system: reaction scope and mechanism
A new class of pincer-like chiral [O−NO−]ZrR2 systems has been developed for efficient asymmetric hydroamination of primary aminoalkenes with up to 94% ee and ≥95% conversion.
Olefin Polymerization by Dinuclear Zirconium Catalysts Based on Rigid Teraryl Frameworks: Effects on Tacticity and Copolymerization Behavior
作者:Jessica Sampson、Gyeongshin Choi、Muhammed Naseem Akhtar、E. A. Jaseer、Rajesh Theravalappil、Hassan Ali Al-Muallem、Theodor Agapie
DOI:10.1021/acs.organomet.7b00015
日期:2017.5.22
of bimetallic catalysts for olefin polymerization, a series of structurally related binuclear zirconium catalysts with bisamine bisphenolate and pyridine bisphenolate ligands connected by rigid teraryl units were synthesized. Anthracene-9,10-diyl and 2,3,5,6-tetramethylbenzene-1,4-diyl were employed as linkers. Bulky SiiPr3 and SiPh3 substituents were used in the position ortho to the phenolate oxygen
为了深入了解用于烯烃聚合的双金属催化剂的行为,合成了一系列结构相关的双核锆催化剂,其中双胺双酚盐和吡啶双酚盐配体通过刚性三芳基单元连接。蒽-9,10-二基和2,3,5,6-四甲基苯-1,4-二基用作连接基。在酚盐氧的邻位使用大的Si i Pr 3和SiPh 3取代基。伪Ç小号和Ç 2观察到双胺双酚盐配体的双核配合物存在对称异构体。通常,与单锆类似物相比,双核催化剂显示出更高的全同立构规整度,异构体之间存在一些差异。发现存在双胺胺的双酚盐二锆络合物具有中等活性(最高达1.5 kg mmol Zr –1 h –1),可在存在下将1-己烯聚合为等规富集的聚1-己烯(高达45%mmmm)。化学计量的三苯甲基或苯甲酸硼酸盐活化剂。在生产等规富集聚丙烯的过程中观察到中等活性(最高2.8 kg mmol Zr –1 h –1和最高25.4%mmmm)。先前提出的基于来自第二金属位点的远端空间效应的立构规
σ-Insertive Mechanism versus Concerted Non-insertive Mechanism in the Intramolecular Hydroamination of Aminoalkenes Catalyzed by Phenoxyamine Magnesium Complexes: A Synthetic and Computational Study
作者:Xiaoming Zhang、Sven Tobisch、Kai C. Hultzsch
DOI:10.1002/chem.201406468
日期:2015.5.18
in a concerted non‐insertive NC ring closure with concurrent amino proton transfer from the amine onto the olefin, effectively combining the insertion and protonolysis step to a single step. The alternative mechanistic scenario involves a reversible olefin insertion step followed by rate‐determining protonolysis. DFT reveals that a proton‐assisted concerted NC/CH bond‐forming pathway is energetically