Selective functionalization of methane, ethane, and higher alkanes by cerium photocatalysis
作者:Anhua Hu、Jing-Jing Guo、Hui Pan、Zhiwei Zuo
DOI:10.1126/science.aat9750
日期:2018.8.17
light to photolytically cleave cerium alkoxide bonds, producing alkoxy radicals that strip H atoms from the hydrocarbons and regenerate the alcohol. The resultant alkyl radicals readily add to azo compounds, olefins, and aromatics. Science, this issue p. 668; see also p. 647 Photolysis of cerium alkoxides forms alkoxy radicals that strip H atoms from hydrocarbons to produce reactive alkyl radicals. With
彻底转变轻烃 天然气中的甲烷、乙烷和丙烷在环境条件下大多呈惰性。它们主要被燃烧以产生热量。胡等人。表明与醇配对的简单铈盐可以在室温下将这些和其他简单的碳氢化合物催化转化为反应性自由基(参见 Kanai 的观点)。该反应依靠光来光解醇铈键,产生烷氧基自由基,从烃中剥离 H 原子并再生醇。生成的烷基很容易加成到偶氮化合物、烯烃和芳烃中。科学,这个问题 p。668; 另见第。647 铈醇盐的光解形成烷氧基自由基,从烃中剥离 H 原子以产生反应性烷基自由基。随着近期天然气产量的飙升,在合成转化中使用甲烷和其他轻烃原料作为起始材料在经济上越来越有吸引力,尽管它在化学上仍然具有挑战性。我们报告了在环境温度下可见光照射下甲烷、乙烷和高级烷烃的光催化 C-H 胺化、烷基化和芳基化的发展。使用丰富、廉价的铈盐作为光催化剂实现了高催化效率(甲烷的转化率高达 2900,乙烷的转化率高达 9700)和选择性。配体
Convenient C(sp<sup>3</sup>)–H bond functionalisation of light alkanes and other compounds by iron photocatalysis
well as enormous chemical challenges. Herein, we report a practical iron-catalysed photoredox system for C(sp3)–H transformation of ethane, propane, and other light alkanes to C–N and C–C bonds under ambient temperature. The present method with abundant and inexpensive iron salts as photocatalysts exhibits high catalytic efficiency (turnover number up to 8000), mild conditions, and the convenience of
轻质烷烃是天然有机碳源,在自然界中分布广泛。将它们转化为具有附加值的精细化学品可提供极具吸引力的经济和生态效益以及巨大的化学挑战。在此,我们报告了一种实用的铁催化光氧化还原系统,用于在环境温度下将乙烷、丙烷和其他轻质烷烃的C(sp 3 )-H 转化为 C-N 和 C-C 键。该方法以丰富且廉价的铁盐为光催化剂,具有催化效率高(转化次数高达8000)、条件温和、无需色谱即可纯化和放大的便利性。Fe( III )和Cl之间的光诱导配体-金属电荷转移-产生高活性的氯自由基,依次充当氢原子转移催化剂。因此,可持续、方便、环保的系统将在天然烷烃的高附加值转化中得到广泛应用,不仅对有机合成有新的启发,而且对催化活性有机/无机材料的设计也有新的启发。
2,2’‐Biquinoline‐Based Recyclable Electroauxiliaries for the Generation of Alkyl Radicals via C−C Bond Cleavage
electroauxiliaries have successfully been developed as suitable reagents for the site-selective generation of alkylradicals. Primary, secondary and tertiaryalkylradicals could be generated and several free radical reactions could be studied. The platform has the advantage of recyclability, which makes these alkylradical precursors superior compared to previous N-heterocyclic electroauxiliaries.