Half-sandwich Ru(η<sup>6</sup>-C<sub>6</sub>H<sub>6</sub>) complexes with chiral aroylthioureas for enhanced asymmetric transfer hydrogenation of ketones – experimental and theoretical studies
作者:Mani Mary Sheeba、Sankaranarayanan Preethi、A. Nijamudheen、Manoharan Muthu Tamizh、Ayan Datta、Louis J. Farrugia、Ramasamy Karvembu
DOI:10.1039/c5cy00774g
日期:——
predicted non-classical, concerted transition states for the ATH reactions. The catalytic activity of Ru–benzene complexes toward asymmetricreduction of ketones was significantly higher compared to that of p-cymene complex analogues. Such enhanced efficiency and product selectivity of Ru–benzene complexes compared to those of Ru–p-cymene complexes were rationalized by the computational study.
的反应将[RuCl 2(η 6 -C 6 H ^ 6)] 2与产生伪八面体半夹心“钢琴凳”络合物的手性配体aroylthiourea。所有Ru(II)配合物的特征在于分析和光谱研究(紫外可见,FT-IR,1 H NMR和13 C NMR)。配体的分子结构(L2和L4)和配合物(2,4和5)由单晶XRD确认。在KOH存在下,使用2-丙醇作为氢源,成功筛选了所有络合物作为酮不对称转移加氢(ATH)的催化剂。ATH反应以优异的收率(高达99%)和非常好的对映选择性(高达99%ee)进行。本催化体系的范围扩展到取代的芳族酮和很少的杂芳族酮。密度泛函理论(DFT)计算可预测ATH反应的非经典协调过渡态。与p相比,Ru-苯配合物对酮的不对称还原的催化活性明显更高。-cymene复杂类似物。通过计算研究可以合理地看出,Ru-苯配合物与Ru- p-肉桂烯配合物相比具有更高的效率和产物选择性。
Chiral (η<sup>6</sup>-<i>p</i>-Cymene)ruthenium(II) Complexes Containing Monodentate Acylthiourea Ligands for Efficient Asymmetric Transfer Hydrogenation of Ketones
作者:Mani Mary Sheeba、Manoharan Muthu Tamizh、Louis J. Farrugia、Akira Endo、Ramasamy Karvembu
DOI:10.1021/om4010548
日期:2014.1.27
structures of the ligands L1 and L3 and complexes 1, 4, and 6 were determined by single-crystal X-ray diffraction methods. In all of the complexes, the ligand is bound to the Ru(II) center only via the sulfur donor atom. This monodentate coordination of the acylthiourea ligands was observed for the first time with ruthenium. The Ru(II) complexes 1–6 all act as efficient catalysts for the asymmetric transfer