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Development of Dynamic Multi-Functional Chiral Molecular Catalysts for Asymmetric Reduction and C-C Bond Formation

用于不对称还原和C-C键形成的动态多功能手性分子催化剂的开发

基本信息

批准号：
12305057
负责人：
IKARIYA Takao
金额：
$ 20.61万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (A)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

A well-defined chiral transition metal amide complex with a M/NH bifunctional unit, Ru(Tsdpen)η^6-arene) or C_p^*M(Tsdpen), (M = Rh, Ir), has sufficient Bronsted basicity to deprotonate 2-propanol or formic acid and acidic organic compounds, leading to a hydrido amine complex and amine complexes bearing a metal bonded C- nucleophile, respectively. Thanks to a rapid and effective interconversion between the amide complex and the amine complex, the chiral amide complex has proven to effect asymmetric transfer hydrogenation of α-substituted aromatic ketones and asymmetric Michael addition to cyclic eneones in a highly stereoselctive manner. The dynamic M/NH bifunctional effect can be applied to the chiral Ru cluster-based catalyst systems generated in situ from Ru_3(CO)_<12> and chiral diiminodiphosphine tetradentate ligands. This chiral cluster effected asymmetric transfer hydrogenation of aromatic ketones in 2-propanol, leading to optically active alcohols with high ee. The dynamic mult … More i-functional effect of both the amide and the amine complexes is responsible for the excellent catalyst performance in terms of high reactivity, selectivity, and practicability.We have demonstrated that supercritical fluids are promising reaction media for molecular catalysis and the utilization of a particular fluid, scCO_2 caused a remarkable enhancement of reactivities and selectivities of molecular catalysts. In order to gain deeper understanding of the reaction mechanism of the molecular catalysis in this unique media, a supercritical fluid nuclear magnetic resonance (scNMR) spectroscopic method has been developed using a commercially available NMR spectrometer equipped with a high-pressure zirconia cell. We found that trialkylphosphite ligands are highly effective for increasing the solubility of dichloropalladium(II) and dichlororuthenium(II) complexes in scCO_2 and the Ru complex promoted rapid vinyl carbamate formation from phenylacetylene, diethylamine, and scCO_2. The scNMR investigation on a dynamic behavior of diethylamine in scCO_2 revealed that formation of N, N-diethylcarbamic acid was reversible and the concentration of the carbamic acid was highly influenced by the pressure and temperature. Less

具有M/NH双功能单元的手性过渡金属酰胺配合物Ru（Tsdpen）η^6-arene）或C_p^*M（Tsdpen），（M = Rh，Ir）具有足够的布朗斯台德碱性以使2-丙醇或甲酸和酸性有机化合物去质子化，分别产生单胺配合物和带有金属键合的C-亲核试剂的胺配合物。由于酰胺络合物和胺络合物之间的快速和有效的相互转化，手性酰胺络合物已被证明以高度立体选择性的方式实现α-取代的芳香酮的不对称转移氢化和环烯酮的不对称Michael加成。动态M/NH双功能效应可应用于由Ru_3（CO）_<12>和手性二亚氨基二膦四齿配体原位生成的手性Ru簇基催化剂体系。该手性簇合物可使芳香酮在异丙醇中发生不对称转移氢化反应，生成具有高ee值的光学活性醇。 ...更多信息酰胺和胺配合物的i-官能化效应是催化剂具有高反应活性、高选择性和高实用性的主要原因，超临界流体是一种很有前途的分子催化反应介质，而超临界CO_2流体的使用可以显著提高分子催化剂的反应活性和选择性。为了更深入地了解在这种独特的介质中分子催化的反应机理，已经开发了超临界流体核磁共振（scNMR）光谱方法，使用配备有高压氧化锆池的市售NMR光谱仪。我们发现亚磷酸三烷基酯配体能有效地增加二氯钯（II）和二氯钌（II）配合物在scCO_2中的溶解度，Ru配合物能促进苯乙炔、二乙胺和scCO_2快速生成氨基甲酸乙烯酯。对二乙胺在scCO_2中的动力学行为的scNMR研究表明，N，N-二乙基氨基甲酸的生成是可逆的，且氨基甲酸的浓度受压力和温度的影响很大。少