Formation of CCbonds from CO2 is a much sought after reaction in organic synthesis. To date, other than CH carboxylations using stoichiometric amounts of metals, base, or organometallic reagents, little is known about CC bond formation. In fact, to the best of our knowledge no catalyticmethylation of CHbondsusing CO2 and H2 has been reported. Described herein is the combination of CO2 and H2 for efficient
由CO 2形成CC键是有机合成中非常需要的反应。迄今为止,除了使用化学计算量的金属,碱或有机金属试剂进行的CH羧化反应外,对CC键的形成知之甚少。实际上,据我们所知,没有报道使用CO 2和H 2催化CH键的甲基化。本文描述的是CO 2和H 2的组合,用于碳亲核试剂(如吲哚,吡咯和富电子芳烃)的有效甲基化。使用低聚甲醛的对比实验显示出与CO 2相似的反应性/ H 2系统。
The Role of Aromatic Radical Cations and Benzylic Cations in the 2,4,6-Triphenylpyrylium Tetrafluoroborate Photosensitized Oxidation of Ring-Methoxylated Benzyl Alcohols in CH<sub>2</sub>Cl<sub>2</sub> Solution
作者:Barbara Branchi、Massimo Bietti、Gianfranco Ercolani、M. Angeles Izquierdo、Miguel A. Miranda、Lorenzo Stella
DOI:10.1021/jo048546h
日期:2004.12.1
stabilities of benzyl alcohol radical cations and benzylcations involved in these processes. A general mechanism for the TPPBF4-photosensitized reactions of ring-methoxylated benzyl alcohols has been proposed, where the α-OH group of the parent substrate acts as the deprotonating base promoting α-C−H deprotonation of the benzyl alcohol radical cation (formed after electron transfer from the benzyl alcohol
Photocatalytic Phenol-Arene C-C and C-O Cross-Dehydrogenative Coupling
作者:Anna Eisenhofer、Johnny Hioe、Ruth M. Gschwind、Burkhard König
DOI:10.1002/ejoc.201700211
日期:2017.4.18
an important role in natural-product synthesis, as ligands in metal catalysis, and in organic functional materials. Their synthesisthrough cross-coupling reactions by two-fold direct C–H activation are important and challenging transformations. In the last decade, a variety of useful oxidative methods have been developed. The key to efficiency and selectivity typically is the application of highly
Trifluoromethanesulfonicacid in acetonitrile was found to efficiently catalyze Friedel–Crafts alkylations of 1,2,4-trimethoxybenzene with a variety of simple or functionalized aldehydes to provide di- or triarylmethanes in high yields. The operationally simple protocol allowed a short synthesis of the phenylpropanoid natural product (−)-tatarinoid C establishing its absolute configuration. Under the
Brönsted acid ionic liquids catalyzed Friedel–Crafts Alkylations of electron-rich arenes with aldehydes
作者:Ailing Wang、Xueliang Zheng、Zhuangzhi Zhao、Changping Li、Yingna Cui、Xuefang Zheng、Jingmei Yin、Guang Yang
DOI:10.1016/j.apcata.2014.05.014
日期:2014.7
including Brönsted acid ionic liquids (BAILs) and traditional ionic liquids were designed and synthesized. BAILs catalyzed Friedel–Crafts (F–C) alkylation was applied in this specific reaction for the first time. And the BAILs showed bifunctional properties acting as catalyst and solvent. Research shows that BAILs can be used for catalyzing F–C alkylations of electron-rich arenes with aromatic or aliphatic