Boronat Mercedes, Corma Avelino, Renz Michael
Instituto de Tecnología Química, UPV-CSIC, Universidad Politécnica de Valencia, Avenida de los Naranjos, s/n, 46022 Valencia, Spain.
J Phys Chem B. 2006 Oct 26;110(42):21168-74. doi: 10.1021/jp063249x.
The mechanism of the Meerwein-Ponndorf-Verley (MPV) reduction of cyclohexanone with 2-butanol catalyzed by Sn-beta and Zr-beta zeolites has been theoretically investigated using density functional theory (DFT) and the cluster approach. An experimental catalytic study has shown that the active sites in the MPV reaction catalyzed by Sn-beta are the same partially hydrolyzed Sn-OH groups that were found to be active for the Baeyer-Villiger (BV) reaction. The computational study indicates that the mechanism of Sn-beta and Zr-beta catalysis is similar, and involves the following steps: adsorption of both the ketone and the alcohol on the Lewis acid center, deprotonation of the alcohol, carbon-to-carbon hydride transfer, proton transfer from the catalyst, and products exchange. As in the aluminum alkoxide catalyzed reaction, the hydride shift occurs through a six-membered transition state, and the role of the hydrolyzed and therefore more flexible M-OH bond is just to facilitate the initial deprotonation of the alcohol.
采用密度泛函理论（DFT）和团簇方法，从理论上研究了Sn-β和Zr-β沸石催化环己酮与2-丁醇发生Meerwein-Ponndorf-Verley（MPV）还原反应的机理。一项实验催化研究表明，Sn-β催化的MPV反应中的活性位点是部分水解的Sn-OH基团，这些基团被发现对Baeyer-Villiger（BV）反应具有活性。计算研究表明，Sn-β和Zr-β催化的机理相似，包括以下步骤：酮和醇在路易斯酸中心上的吸附、醇的去质子化、碳到碳的氢化物转移、质子从催化剂的转移以及产物交换。与醇铝催化的反应一样，氢化物转移通过六元过渡态发生，水解后更灵活的M-OH键的作用仅仅是促进醇的初始去质子化。
