An efficient method for the synthesis of aryl and heteroaryl chlorides is described. The reactions of aryl and heteroaryl bromides with tetramethylammonium chloride proceeded smoothly in the presence of a copper catalyst under mild reaction conditions to produce the corresponding chlorides in satisfactory to excellent yields.
functionalization of arenes that is complementary to classical aromatic substitution reactions remains a long‐standing quest in organic synthesis. Exploiting the generation of halenium ion through oxidative process and the protonation of the nitrogen containing function in HF/SbF5, the chlorination and iodination of classically inert Csp2−H bonds of aromatic amines occurs. Furthermore, the superacid‐promoted (poly)protonation
Mild CH Halogenation of Anilides and the Isolation of an Unusual Palladium(I)-Palladium(II) Species
作者:Robin B. Bedford、Mairi F. Haddow、Charlotte J. Mitchell、Ruth L. Webster
DOI:10.1002/anie.201101606
日期:2011.6.6
Reducing the load: A facile palladium‐catalyzed ortho‐selective bromination and chlorination of anilides occurs under aerobic conditions at room temperature when N‐halosuccinimides (NXS) are used in the presence of p‐toluenesulfonic acid (PTSA). The orthopalladated PTSA complex is not only catalytically competent but also undergoes a reductive process to yield an unusual PdI–PdII tetramer (see structure;
减少负荷:在有氧条件下,在对甲苯磺酸(PTSA)的存在下使用N-卤代琥珀酰亚胺(NXS)时,在室温下好氧条件下,钯的催化邻位溴化和氯离子氯化很容易进行。正统的PTSA配合物不仅具有催化能力,而且还经过还原过程生成不寻常的Pd I –Pd II四聚体(见结构; Pd绿色,O红色,S黄色和C灰色)。
Cobalt(<scp>ii</scp>)-catalyzed regioselective C–H halogenation of anilides
作者:Ze-lin Li、Kang-kang Sun、Chun Cai
DOI:10.1039/c8ob01448e
日期:——
A cobalt-catalyzed regioselective C–H halogenation methodology is reported herein. The highlight of this work is the highly selective C–H functionalization of anilides, which results in high-yielding, versatile, and practical halogenated products. Thereby, brominations, chlorinations and iodinations of many electron-rich and electron-deficient anilides were achieved in a highly selective fashion. Mechanistic
A New Palladium Precatalyst Allows for the Fast Suzuki−Miyaura Coupling Reactions of Unstable Polyfluorophenyl and 2-Heteroaryl Boronic Acids
作者:Tom Kinzel、Yong Zhang、Stephen L. Buchwald
DOI:10.1021/ja1073799
日期:2010.10.13
Boronic acids which quickly deboronate under basic conditions, such as polyfluorophenylboronic acid and five-membered 2-heteroaromatic boronic acids, are especially challenging coupling partners for Suzuki-Miyaura reactions. Nevertheless, being able to use these substrates is highly desirable for a number of applications. Having found that monodentate biarylphosphine ligands can promote these coupling processes, we developed a precatalyst that forms the catalytically active species under conditions where boronic acid decomposition is slow. With this precatalyst, Suzuki-Miyaura reactions of a wide range of (hetero)aryl chlorides, bromides, and triflates with polyfluorophenyl, 2-furan, 2-thiophene, and 2-pyrroleboronic acids and their analogues proceed at room temperature or 40 degrees C in short reaction times to give the desired products in excellent yields.