Design and Syntheses of Palladium Complexes of NNN/CNN Pincer Ligands: Catalyst for Cross Dehydrogenative Coupling Reaction of Heteroarenes
作者:Vikki N. Shinde、Nattamai Bhuvanesh、Anil Kumar、Hemant Joshi
DOI:10.1021/acs.organomet.9b00695
日期:2020.1.27
of palladium(II) pincer complexes having NNN and CNN coordinationmodes. The new complexes were fully characterized with the help of 1H and 13C1H} NMR, HRMS, and IR spectroscopy. The structure and bonding modes of complexes were further authenticated with the help of single-crystal X-ray diffraction. Thermally robust and moisture-/air-insensitive palladium pincer complexes C1–C4 have been used as
该报告描述了具有NNN和CNN配位模式的新型钯(II)钳形配合物的简单合成。借助1 H和13 C 1 H} NMR,HRMS和IR光谱对新配合物进行了全面表征。借助单晶X射线衍射进一步验证了配合物的结构和键合模式。具有热稳定性且对湿气/空气不敏感的钯夹钳复合物C1 - C4已被用作两个杂芳烃的交叉脱氢偶联(CDC)反应的催化剂,发现非常有效。该催化剂仅用1.0 mol%的催化剂即可成功活化包括苯并咪唑,咪唑,苯并噻唑,咪唑并吡啶,噻吩和呋喃在内的多种杂芳烃的C–H键,仅偶联剂的收率就很高。该催化剂对CHO,COMe,COOMe,COOEt,CONHPh,Me,CN,Br和Cl等官能团具有极好的耐受性。此外,该催化剂可重复使用多达四个反应周期,而效率仅有很小的损失。通过控制实验研究了CDC反应的机理,已表明NNN钳形配体(C5)的乙酸钯类似物是活性催化剂。
Catalyst- and Supporting-Electrolyte-Free Electrosynthesis of Benzothiazoles and Thiazolopyridines in Continuous Flow
作者:Ana A. Folgueiras-Amador、Xiang-Yang Qian、Hai-Chao Xu、Thomas Wirth
DOI:10.1002/chem.201705016
日期:2018.1.9
N‐arylthioamides have been converted to the corresponding benzothiazoles in good to excellent yields and with high current efficiencies. This transformation is achieved using only electricity and laboratory grade solvent, avoiding degassing or the use of inert atmosphere. This work highlights three advantages of electrochemistry in flow, which is (i) a supporting electrolyte‐free reaction, (ii) an easy scale‐up
Palladium-Catalyzed Dehydrogenative Cross-Couplings of Benzazoles with Azoles
作者:Wei Han、Peter Mayer、Armin R. Ofial
DOI:10.1002/anie.201006208
日期:2011.2.25
Different enough: Palladium‐catalyzed cross‐couplings of benzazoles with imidazoles, oxazoles, and thiazoles furnish unsymmetrical 2,2′‐bisheteroaryls in high yield (see scheme). These oxidative CC bond formations use the selective cleavage of the CH bond at C2 in the two coupling partners and are robust enough to be conducted under normal air atmosphere.
Halo-Bridged Abnormal NHC Palladium(II) Dimer for Catalytic Dehydrogenative Cross-Coupling Reactions of Heteroarenes
作者:Sreejyothi P、Samaresh Chandra Sau、Pavan K. Vardhanapu、Swadhin K. Mandal
DOI:10.1021/acs.joc.8b01053
日期:2018.8.17
This work describes the dehydrogenative coupling of heteroarenes using a dimeric halo-bridged palladium(II) catalyst bearing an abnormal NHC (aNHC) backbone. The catalyst can successfully activate the C–Hbond of a wide range of heteroarenes, which include benzothiazole, benzoxazole, thiophene, furan, and N-methylbenzimidazole. Further, it exhibited good activity for heteroarenes bearing various functional
Binuclear copper(II) complex with 2-imidazolylbenzothiazole and bridged chloride ligands
作者:Elena S. Barskaya、Artem V. Rzheutskiy、Anna A. Moiseeva、Victor A. Tafeenko、Nikolay V. Zyk、Elena K. Beloglazkina
DOI:10.1016/j.mencom.2019.07.030
日期:2019.7
chloro-bridged copper(II) complex of L2Cu2Cl4 composition [L stands for 2-(1H-imidazol-4-yl)-1,3-benzothiazole ligand] was obtained from CuCl2·2H2O and ligand L in ethanol. According to X-ray diffraction studies, the complex is a dimer with two bridgedchlorideligands and two chloride ions coordinated with only copper atom. Cyclic voltammetry demonstrated the stability of dimeric structure of the complex in DMF