Transition-Metal-Free Synthesis of 2-Substituted Benzothiazoles from Nitrobenzenes, Methylheteroaryl Compounds, and Elemental Sulfur, Based on Nitro-Methyl Redox-Neutral Cyclization
has been shown to promote the efficient synthesis of 2-substituted benzothiazoles from easily available nitrobenzenes, methyl-heteroaryl compounds, and elemental sulfur in the absence of transition-metal catalysts. The 2-substituted benzothiazoles were obtained in reasonable yields through the sulfuration of electron-deficient C–H bonds with elemental sulfur. This synthetic methodology also affords
PdCl(dppb)(C3H5) as a catalyst, a range of heteroaryl derivatives undergoes coupling via C–Hbondactivation/functionalization reaction with chloropyridines or chloroquinolines in low to high yields. This air-stable catalyst can be used with a wide variety of substrates. The position of the chloro substituent on pyridines has a minor influence on the yields. On the other hand, the nature on the heteroaryl derivative
芳基氯化物与杂芳烃的直接偶联将具有可持续发展的巨大优势,因为它们的成本更低,质量更轻,可用化合物的多样性更大,并且还因为仅形成了与副产物碱有关的HCl和减少制备这些化合物的步骤数。我们观察到通过使用PdCl(dppb)(C 3 H 5)作为催化剂,一系列杂芳基衍生物通过C–H键活化/官能化反应与氯吡啶或氯喹啉进行低至高收率的偶联。这种空气稳定的催化剂可与多种基材一起使用。吡啶上氯取代基的位置对收率影响很小。另一方面,杂芳基衍生物的性质具有很大的影响。使用苯并恶唑,噻吩或噻唑衍生物可获得最高的收率。氯吡啶与呋喃的偶联也得到了预期的产物,但是产率低至中等。
Palladium‐Catalysed Direct C‐H Activation/Arylation of Heteroaromatics: An Environmentally Attractive Access to Bi‐ or Polydentate Ligands
作者:Fazia Derridj、Aditya L. Gottumukkala、Safia Djebbar、Henri Doucet
DOI:10.1002/ejic.200800143
日期:2008.6
Bi- or polydentateligands based on heterocycles can be easily prepared by palladium-catalysed C–H bond activation of heteroaromatics followed by heteroarylation with heteroaryl bromides. A variety of heteroaromatics such as furans, thiophenes, pyridines, thiazoles or oxazole derivatives have been employed and moderate to good yields were generally obtained using the air-stable complex [PdCl(dppb)(C3H5)]
Exploring simple ancillary ligands in copper-based dye-sensitized solar cells: effects of a heteroatom switch and of co-sensitization
作者:Frederik J. Malzner、Alessandro Prescimone、Edwin C. Constable、Catherine E. Housecroft、Markus Willgert
DOI:10.1039/c6ta10947k
日期:——
Photoconversion efficiencies reaching 40% that of the ruthenium dye N719 are achieved in n-type DSCs using structurally simple heteroleptic copper(i) dyes; the effects on DSC performance of using mixed copper(i) dyes are presented.