Tamura Masazumi, Tamura Riku, Takeda Yasuyuki, Nakagawa Yoshinao, Tomishige Keiichi
Graduate School of Engineering, Tohoku University, Aoba 6-6-07, Aramaki, Aoba-ku, Sendai 980-8579 (Japan).
Chemistry. 2015 Feb 9;21(7):3097-107. doi: 10.1002/chem.201405769. Epub 2014 Dec 29.
Hydrogenation of amino acids to amino alcohols is a promising utilization of natural amino acids. We found that MoOx -modified Rh/SiO2 (Rh-MoOx /SiO2 ) is an efficient heterogeneous catalyst for the reaction at low temperature (323 K) and the addition of a small amount of MoOx drastically increases the activity and selectivity. Here, we report the catalytic potential of Rh-MoOx /SiO2 and the results of kinetic and spectroscopic studies to elucidate the reaction mechanism of Rh-MoOx /SiO2 catalyzed hydrogenation of amino acids to amino alcohols. Rh-MoOx /SiO2 is superior to previously reported catalysts in terms of activity and substrate scope. This reaction proceeds by direct formation of an aldehyde intermediate from the carboxylic acid moiety, which is different from the reported reaction mechanism. This mechanism can be attributed to the reactive hydride species and substrate adsorption caused by MoOx modification of Rh metal, which results in high activity, selectivity, and enantioselectivity.
将氨基酸氢化为氨基醇是天然氨基酸的一种很有前景的利用方式。我们发现，MoOx修饰的Rh/SiO2（Rh-MoOx /SiO2）是一种在低温（323 K）下该反应的高效多相催化剂，添加少量的MoOx会显著提高活性和选择性。在此，我们报告Rh-MoOx /SiO2的催化潜力以及动力学和光谱研究结果，以阐明Rh-MoOx /SiO2催化氨基酸氢化为氨基醇的反应机理。Rh-MoOx /SiO2在活性和底物范围方面优于先前报道的催化剂。该反应通过羧酸部分直接形成醛中间体进行，这与报道的反应机理不同。这种机理可归因于Rh金属的MoOx修饰导致的活性氢化物物种和底物吸附，从而产生高活性、选择性和对映选择性。
