<sup>183</sup>
W NMR Spectroscopy Guides the Search for Tungsten Alkylidyne Catalysts for Alkyne Metathesis
作者:Julius Hillenbrand、Markus Leutzsch、Christopher P. Gordon、Christophe Copéret、Alois Fürstner
DOI:10.1002/anie.202009975
日期:2020.11.23
Triarylsilanolates are privileged ancillary ligands for molybdenum alkylidyne catalysts for alkynemetathesis but lead to disappointing results and poor stability in the tungsten series. 1H,183W heteronuclear multiple bond correlation spectroscopy, exploiting a favorable 5J‐coupling between the 183W center and the peripheral protons on the alkylidyne cap, revealed that these ligands upregulate the Lewis acidity
三芳基硅烷醇盐是用于炔复分解的钼亚烷基催化剂的优先辅助配体,但在钨系列中导致令人失望的结果和较差的稳定性。1 H, 183 W 异核多重键相关光谱,利用183 W 中心与烷叉帽上的外围质子之间有利的5 J耦合,揭示了这些配体将路易斯酸度上调到一定程度,使得环丁二烯钨在最初形成[2+2]环加成步骤过度稳定并且催化周转停止。以183 W NMR 位移作为中心原子路易斯酸度的代表,并通过烷叉单元的化学位移张量分析,重新审视了配体设计,并制备了更强的 π 供体全醇盐配体。新的膨胀螯合物具有缓和的路易斯酸度,并且在速率和官能团相容性方面优于带有单齿叔丁氧基配体的经典Schrock催化剂。
“Canopy Catalysts” for Alkyne Metathesis: Molybdenum Alkylidyne Complexes with a Tripodal Ligand Framework
作者:Julius Hillenbrand、Markus Leutzsch、Ektoras Yiannakas、Christopher P. Gordon、Christian Wille、Nils Nöthling、Christophe Copéret、Alois Fürstner
DOI:10.1021/jacs.0c04742
日期:2020.6.24
certain stability toward water, which marks a big leap forward in metal alkylidyne chemistry in general. At the same time, they tolerate many donor sites, including basic nitrogen and numerous heterocycles. This aspect is substantiated by applications to polyfunctional (natural) products. A combined spectroscopic, crystallographic, and computational study provides insights into structure and electronic
A new type of molybdenum alkylidyne catalysts for alkynemetathesis is described, which is distinguished by an unconventional podand topology. These structurally well-definedcomplexes are easy to make on scale and proved to be tolerant toward numerous functional groups; even certain protic substituents were found to be compatible. The new catalysts were characterized by X-ray crystallography and by
描述了一种用于炔复分解的新型钼亚烷基催化剂,其特点是非常规的荚状拓扑结构。这些结构明确的复合物很容易大规模制造,并且被证明对多种官能团具有耐受性;甚至发现某些质子取代基是相容的。新催化剂通过 X 射线晶体学和光谱手段(包括 95 Mo NMR)进行了表征。
Optimized Synthesis, Structural Investigations, Ligand Tuning and Synthetic Evaluation of Silyloxy-Based Alkyne Metathesis Catalysts
groups have the advantage that they are more stable within the coordination sphere of a high‐valent molybdenum center than tert‐alkoxides, which commonly served as ancillary ligands in previous generations of alkyne metathesis catalysts. From a practical point of view it is important to note that complexes of the general type [(Ar3SiO)3MoX] (X = N, CR; R = aryl, alkyl, Ar = aryl) can be rendered air‐stable
具有三芳基硅烷醇酸酯配体的钼的氮化物和亚烷基络合物是各种炔烃复分解反应的极好(预)催化剂,因为它们结合了高活性和对极性和/或敏感官能团的出色耐受性。结构和反应性数据表明,这种有希望的应用前景是由于高价钼中心的特征与所选Ar 3 SiO基团的电子和空间特征之间的良好匹配而产生的。这种相互作用确保了中心原子上路易斯酸度的均衡水平,这对于高活性至关重要。此外,笨重的硅烷醇化物虽然不利于有效的亚烷基单元的双分子分解,但不会阻碍底物的结合。另外,Ar 3SiO基的优势在于,它们在高价钼中心的配位范围内比叔醇盐更稳定,后者在上一代炔烃复分解催化剂中通常用作辅助配体。从实际的角度来看是要注意的一般类型[(AR的该配合物是重要的3的SiO)3 MoX](X = N,CR; R =芳基,烷基中,Ar =芳基)可以呈现空气在1,10-菲咯啉,2,2'-联吡啶或其衍生物的帮助下稳定。尽管所得的加合物本身具有催
CATALYSTS FOR THE ALKYNE METATHESIS
申请人:Fuerstner Alois
公开号:US20130144102A1
公开(公告)日:2013-06-06
Organometallic compounds of the general formula (I), in which M=Mo, W, are claimed.