Dynamic Structural Change of the Self-Assembled Lanthanum Complex Induced by Lithium Triflate for Direct Catalytic Asymmetric Aldol-Tishchenko Reaction
作者:Yoshihiro Horiuchi、Vijay Gnanadesikan、Takashi Ohshima、Hyuma Masu、Kosuke Katagiri、Yoshihisa Sei、Kentaro Yamaguchi、Masakatsu Shibasaki
DOI:10.1002/chem.200500442
日期:2005.9.5
addition of LiOTf using 13C NMR spectroscopy, electronspray ionization mass spectrometry (ESI-MS), and cold-spray ionization mass spectrometry (CSI-MS). X-ray crystallography revealed that the structure of the newly generated self-assembled complex was a binuclear [La2Li4(binaphthoxide)5] complex 6. A reverse structural change of complex 6 to LLB by the addition of one equivalent of Li2(binol) was also confirmed
描述了直接催化不对称醛醇-季申科反应的发展及其催化剂的性质。[LaLi3(binol)3](LLB)促进了各种苯丙酮衍生物与芳香醛的aldol-Tishchenko反应,并且通过添加三氟甲磺酸锂(LiOTf)显着提高了反应性和对映选择性。首先,我们通过使用13C NMR光谱,电子喷雾电离质谱(ESI-MS)和冷喷雾电离质谱(CSI-MS)添加LiOTf观察到LLB的动态结构变化。X射线晶体学分析表明,新生成的自组装复合物的结构为双核[La2Li4(binaphthoxide)5]复合物6。ESI-MS和实验结果也证实了通过添加一当量的Li2(binol),复合物6向LLB的反向结构变化。对直接催化的不对称醛醇-季申科反应的剧烈浓度影响表明,将LiOTf添加到LLB中产生了活性的低聚催化剂种类。