3D-QSPR models for predicting the enantioselectivity and the activity for asymmetric hydroformylation of styrene catalyzed by Rh-diphosphane
3D-QSPR models for predicting the enantioselectivity and the activity for asymmetric hydroformylation of styrene catalyzed by Rh-diphosphane
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DOI：
10.1039/c2cy20089a
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发表时间：
2012-01-01
影响因子：
5
通讯作者：
Carbo, Jorge J.
中科院分区：
文献类型：
--
作者：
Aguado-Ullate, Sonia;Guasch, Laura;Carbo, Jorge J.
本文描述了铑 - 双膦配体催化苯乙烯不对称氢甲酰化反应的定量结构 - 对映选择性和 - 活性关系的发展。我们使用了从密度泛函理论（DFT）计算得出的三维空间和静电类型的相互作用场，并使用网格独立描述符（GRIND）方法生成了与取向无关的描述符。所获得的定量结构 - 性质关系（QSPR）模型具有统计学意义和预测能力。基于局部曲率电子密度等值面（该面考虑了催化剂形状）的空间类型三维场（MSF）得到了最具预测性的对映选择性模型（\(r^{2}=0.92\)，\(q^{2}=0.68\)）。我们使用基于形状和静电的三维场的组合得到了最具预测性的活性模型（\(r^{2}=0.99\)，\(q^{2}=0.74\)）。使用具有化学意义的描述符有助于深入了解控制催化活性和选择性的因素。预测效果最差的配体凯立菲（kelliphite）对赤道 - 顶点配位的偏好最低且选择性差，这表明其内在的对映异位区分能力可能会因双赤道路径的出现而丧失。选择性催化剂铑 - 奇拉菲（Rh - chiraphite）、 - 比纳平（Rh - binapine）、 - 二氮杂磷杂环戊烷（Rh - diazaphospholane）和 - 扬福斯（Rh - yanphos）与铑 - 联萘膦（Rh - binaphos）表现出相同的模式，而铑 - 联萘膦的立体诱导起源是已知的：顶点位置的手性区分了一种烯烃配位路径和一种对映体。在磷原子上具有吸电子基团的配体，如奇拉菲、凯立菲、联萘膦和二氮杂磷杂环戊烷，会降低配体的碱性并有效提高催化活性。然而，活性的起源背后存在更复杂的关系，并且还需要考虑催化剂的形状，例如对于苯 - BPE配体。与先前研究的比较表明，降低反应中心有利于烯烃配位和插入的空间位阻也会提高催化活性。
This paper describes the development of quantitative structure-enantioselectivity and-activity relationships for the asymmetric hydroformylation of styrene by Rh-diphosphane. We used 3D steric- and electrostatic-type interaction fields derived from DFT calculations, and generated alignment-independent descriptors using GRid INdependent Descriptor (GRIND) methodology. The obtained QSPR models showed statistical significance and predictive ability. The most predictive model for enantioselectivity was obtained using steric-type 3D fields (MSF) based on the local curvature electron density isosurface that accounts for catalyst shape (r(2) = 0.92, q(2) = 0.68). We obtained the most predictive model for activity using a combination of shape- and electrostatic-based 3D fields (r(2) = 0.99, q(2) = 0.74). The use of chemically meaningful descriptors provides insight into the factors governing catalytic activity and selectivity. The worst predicted ligand, kelliphite, showed the lowest preference for equatorial-apical coordination and low selectivity, which suggests that its intrinsic enantiotopic differentiation capacity can be lost through the occurrence of bis-equatorial paths. The selective catalysts Rh-chiraphite, -binapine, -diazaphospholane, and -yanphos showed the same pattern as Rh-binaphos, for which the origin of stereoinduction is known: the chirality at the apical site discriminates one alkene coordination path and one enantiomer. Ligands with electron withdrawing groups at phosphorus atoms such as chiraphite, kelliphite, binaphos, and diazaphospholane reduce ligand basicity and promote catalytic activity effectively. However, more complex relationships underlie the origin of activity, and the shape of the catalyst also needs to be considered such as for the Ph-BPE ligand. Comparison with previous studies suggests that reduction of the steric hindrance at the reaction centre which favors alkene coordination and insertion would also promote catalytic activity.