A palladium-catalyzed tandem addition/cyclization of 2-(2-aminoaryl)acetonitriles with arylboronic acids has been developed for the first time, achieving a new strategy for direct construction of indole skeletons. This system shows good functional group tolerance and remarkable chemoselectivity. In particular, the halogen (e.g., bromo and iodo) substituents are amenable to further synthetic elaborations
Direct C-Arylation of Free (NH)-Indoles and Pyrroles Catalyzed by Ar−Rh(III) Complexes Assembled In Situ
作者:Xiang Wang、Benjamin S. Lane、Dalibor Sames
DOI:10.1021/ja050279p
日期:2005.4.1
Ar-Rh(III) pivalate complexes assembled in situ from the reaction of [RhCl(coe)2]2 (coe = cis-cyclooctene), [p-(CF3)C6H4]3P, and CsOPiv effectively catalyzed the direct C-arylation of free (NH)-indoles and (NH)-pyrroles in good yields and with high regioselectivity. The reaction displayed excellent functional group compatibility and low moisture sensitivity. Kinetics studies support a mechanism involving
Selective C-Arylation of Free (NH)-Heteroarenes via Catalytic C−H Bond Functionalization
作者:Bengü Sezen、Dalibor Sames
DOI:10.1021/ja034848+
日期:2003.5.1
palladium-catalyzed arylation of a broad spectrum of free (NH)-heteroarenes has been developed (indole, pyrrole, pyrazole, 2-phenylimidazole, imidazole, benzimidazole, and purine). Remarkable selectivity has been achieved in the presence of MgO base, providing single C-arylation products, while no N-arylation and no bis-arylation products have been detected. In the case of free imidazole, exclusive C-4 arylation may
was developed through palladium-catalyzed tandem addition/cyclization of potassium aryltrifluoroborates with aliphatic nitriles in aqueous medium. The use of water as the reaction medium makes the synthesis process environmentally benign. A plausible mechanism for the formation of 2-arylindoles involving sequential nucleophilic addition followed by an intramolecular cyclization is proposed. Moreover
Pd/β-cyclodextrin-catalyzed C–H functionalization in water: a greener approach to regioselective arylation of (NH)-indoles with aryl bromides
作者:Peng Xu、Xin Hong Duan
DOI:10.1039/d1nj03400f
日期:——
A greener and more practical strategy for the site-selective C–H arylation of (NH)-indoles via coupling of (hetero)aryl bromides was developed, in which β-cyclodextrin, acting as both a ligand for Na2PdCl4 and a host for indoles, enables the reactions to occur easily in water. The key advantage of this method is the ingenious merging of aqueous homogeneous catalysis and ligand mediation, leading to
开发了一种更环保、更实用的策略,用于通过(杂)芳基溴化物的偶联对 (NH)-吲哚进行位点选择性 C-H 芳基化,其中 β-环糊精作为 Na 2 PdCl 4的配体和吲哚的宿主,使反应在水中容易发生。这种方法的关键优势是水相均相催化和配体介导的巧妙融合,导致具有广泛底物范围和官能团耐受性的 C3-芳基吲哚的高度区域选择性形成。此外,区域选择性可以通过改变碱基的性质而从 C3 位切换到 C2 位,而无需使用 ArI 作为底物。