Longwitz Lars, Werner Thomas
Organocatalysis, Leibniz-Institute for Catalysis, Albert-Einstein-Straße 29a, Rostock, Germany.
Angew Chem Int Ed Engl. 2020 Feb 10;59(7):2760-2763. doi: 10.1002/anie.201912991. Epub 2020 Jan 21.
The carbon-carbon double bond of unsaturated carbonyl compounds was readily reduced by using a phosphetane oxide catalyst in the presence of a simple organosilane as the terminal reductant and water as the hydrogen source. Quantitative hydrogenation was observed when 1.0 mol % of a methyl-substituted phosphetane oxide was employed as the catalyst. The procedure is highly selective towards activated double bonds, tolerating a variety of functional groups that are usually prone to reduction. In total, 25 alkenes and two alkynes were hydrogenated to the corresponding alkanes in excellent yields of up to 99 %. Notably, less active poly(methylhydrosiloxane) could also be utilized as the terminal reductant. Mechanistic investigations revealed the phosphane as the catalyst resting state and a protonation/deprotonation sequence as the crucial step in the catalytic cycle.
在简单有机硅烷作为终端还原剂和水作为氢源存在的情况下，使用氧化磷杂环丁烷催化剂可轻松还原不饱和羰基化合物的碳 - 碳双键。当使用1.0 mol％的甲基取代氧化磷杂环丁烷作为催化剂时，观察到定量氢化反应。该方法对活化双键具有高度选择性，能耐受各种通常易于还原的官能团。总共有25种烯烃和两种炔烃被氢化为相应的烷烃，产率高达99％，效果极佳。值得注意的是，活性较低的聚甲基氢硅氧烷也可作为终端还原剂。机理研究表明，膦是催化剂的静止状态，质子化/去质子化序列是催化循环中的关键步骤。
