CATALYTIC DISPROPORTIONATION OF ALDEHYDES WITH RUTHENIUM COMPLEXES
CATALYTIC DISPROPORTIONATION OF ALDEHYDES WITH RUTHENIUM COMPLEXES
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DOI：
10.1021/om00057a019
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发表时间：
1991-11-01
期刊：
影响因子：
2.8
通讯作者：
SHVO, Y
中科院分区：
文献类型：
--
作者：
MENASHE, N;SHVO, Y
发现钌配合物[（C_4Ph_4COHOCC_4Ph_4）（μ-H）][（CO）_4Ru_2]（2）以及其它同结构的钌配合物在催化量的甲酸存在下催化醛的均相双分子缩合反应生成酯：2 RCHO-> RCOOCH_2 R。 发现该反应是通用的，并且与各种脂肪族和芳香族醛相容，并且可以在温和条件下在存在或不存在溶剂的情况下进行。 它的特点是具有良好的效率与初始周转频率达到5000 h-1，测得的总周转数约。20000，和高转化率，产率和选择性。 发现增加金属和配体上的电子密度可加速反应。 动力学研究表明，速率= k[催化剂]1/2[醛]。 该速率还取决于初始甲酸浓度。 配合物2与甲酸的化学计量反应，通过红外光谱监测，揭示了活性催化物种的身份。 以PhCDO和DCOOD为反应物，未发现动力学同位素效应。 据此提出了醛双分子转化成酯的反应机理和详细的催化循环。
It was discovered that the ruthenium complex [(C4Ph4COHOCC4Ph4)(mu-H)][(CO)4Ru2] (2), as well as other isostructural Ru complexes, in the presence of a catalytic amount of formic acid, catalyzes the homogeneous bimolecular disproportionation reaction of aldehydes to give esters: 2RCHO --> RCOOCH2R. The reaction was found to be general and compatible with a variety of aliphatic and aromatic aldehydes and can be carried out in the presence or absence of solvent under mild conditions. It is characterized by an excellent efficiency with an initial turnover frequency reaching 5000 h-1, a measured overall turnover number of ca. 20 000, and high conversion, yield, and selectivity. Increasing the electron density on the metal and the ligand was found to accelerate the reaction. Kinetic studies indicate that the rate = k[catalyst]1/2[aldehyde]. The rate also depends on the initial formic acid concentration. A stoichiometric reaction of complex 2 with formic acid, monitored by infrared spectroscopy, shed light on the identity of the active catalytic species. No kinetic isotope effect could be detected by using PhCDO and DCOOD as reactants. Consequently, a mechanism and a detailed catalytic cycle for the bimolecular transformation of aldehydes to esters were proposed.