Room-Temperature Kumada Cross-Coupling of Unactivated Aryl Chlorides Catalyzed by <i>N</i>-Heterocylic Carbene-Based Nickel(II) Complexes
作者:Zhenxing Xi、Bin Liu、Wanzhi Chen
DOI:10.1021/jo800197u
日期:2008.5.1
The Kumada cross-coupling reaction of a variety of unactivated aryl chlorides, vinyl chlorides, and heteroaryl chlorides catalyzed by nickel(II) complexes containing pyridine-functionalized NHC ligands is described. The catalysts are so active that the reactions proceed at room temperature in excellent yields.
Synthesis of Highly Substituted Arenes via Cyclohexadiene–Alkene C–H Cross Coupling and Aromatization
作者:Anup Bhunia、Armido Studer
DOI:10.1021/acscatal.8b00083
日期:2018.2.2
The development of a cross-coupling method for the regioselective β-alkenylation of 2,5-cyclohexadiene carboxylic acid derivatives to form ortho-alkenylarenes through in situ decarboxylation and aromatization is described. The carboxylic acid functionality is used as a traceless directing group for efficient and mild β-alkenylation. The modular sequence comprises a reductive Birch α-alkylation, ionic
<i>N</i>-Methylphenothiazine <i>S</i>-Oxide Enabled Oxidative C(sp<sup>2</sup>)–C(sp<sup>2</sup>) Coupling of Boronic Acids with Organolithiums via Phenothiaziniums
we report the development of a transition-metal-free oxidative C(sp2)–C(sp2) coupling of readily available boronic acids and organolithiums via phenothiazinium ions. Various biaryl, styrene, and diene derivatives were obtained using this reaction system. The key to this process is N-methylphenothiazine S-oxide (PTZSO), which allows efficient conversion of boronic acids to phenothiazinium ions. The mechanism
Facile and highly chemoselective synthesis of benzil derivatives via oxidation of stilbenes in an I2–H2O system
作者:Xianghua Zeng、Chengxia Miao、Shoufeng Wang、Chungu Xia、Wei Sun
DOI:10.1039/c3ra41489b
日期:——
A facile and highlychemoselective protocol for the synthesis of benzil derivatives has been developed by oxidation of stilbenes in an I2–H2O system under air. Notably, the method was applicable to 26 examples and provided up to 98% yield, avoiding the use of acid, metal catalysts and so on.
(E)-(2-Bromoethenyl)dibromoborane, prepared readily by the bromoboration of acetylene with tribromoborane, can be used as an effective precursor for the stereoselective synthesis of (E)-1,2-disubstituted ethenes.