1172121-08-2Relevant academic research and scientific papers
Carboxylic acids as traceless directing groups for the rhodium(iii)-catalyzed decarboxylative C-H arylation of thiophenes
Zhang, Yuanfei,Zhao, Huaiqing,Zhang, Min,Su, Weiping
, p. 3817 - 3821 (2015)
A rhodium(III)-catalyzed carboxylic acid directed decarboxylative C-H/C-H cross-coupling of carboxylic acids with thiophenes has been developed. With a slight adjustment of the reaction conditions based on the nature of the substrates, aryl carboxylic acids with a variety of substituents could serve as suitable coupling partners, and a broad variety of functional groups were tolerated. This method provides straightforward access to biaryl scaffolds with diverse substitution patterns, many of which have conventionally been synthesized through lengthy synthetic sequences. An illustrative example is the one-step gram-scale synthesis of a biologically active 3,5-substituted 2-arylthiophene by way of the current method. Who was in control? A rhodium(III)-catalyzed carboxylic acid directed decarboxylative C-H/C-H cross-coupling of benzoic acids with thiophenes has been developed. This method provides straightforward access to biaryl scaffolds with diverse substitution patterns, many of which previously required lengthy synthetic sequences.
Well-Defined Palladium N-Heterocyclic Carbene Complexes: Direct C-H Bond Arylation of Heteroarenes
Kumar, Anuj,Kumar, Manoj,Verma, Akhilesh K.
, p. 13983 - 13996 (2020/11/20)
A series of palladium N-heterocyclic carbene (NHC) complexes of type trans-{(NHC)PdCl2L} (L = C5H5N, 3-ClC5H4N, and PPh3) (3-5) have been developed as efficient precatalysts for direct C-H bond arylation of various heteroarenes. In particular, an in situ generated new NHC ligand derived from {1,3-di-(2,6-diethylphenyl)acenaphtho[1,2-d] imidazolium} chloride (2) is used for the stabilization of the palladium metal center. Among the screened palladium precatalysts (3-5), the most active PEPPSI themed complex (3) was successfully employed toward direct C-H bond arylation of various heteroarenes and aryl bromides. A range of functional groups on aryl bromides as well as on heteroarenes sustained throughout the standard reaction conditions for easy access of various arylated heterocyclic compounds. Significantly, the utility of the protocol was demonstrated by the effective synthesis of a precursor of raloxifene, a selective estrogen receptor modulator.
Rh(III)-catalyzed decarboxylative ortho -heteroarylation of aromatic carboxylic acids by using the carboxylic acid as a traceless directing group
Qin, Xurong,Sun, Denan,You, Qiulin,Cheng, Yangyang,Lan, Jingbo,You, Jingsong
supporting information, p. 1762 - 1765 (2015/04/14)
Highly selective decarboxylative ortho-heteroarylation of aromatic carboxylic acids with various heteroarenes has been developed through Rh(III)-catalyzed two-fold C-H activation, which exhibits a wide substrate scope of both aromatic carboxylic acids and heteroarenes. The use of naturally occurring carboxylic acid as the directing group avoids troublesome extra steps for installation and removal of an external directing group.
Direct C-H arylation of thiophenes at low catalyst loading of a phosphine-free bis(alkoxo)palladium complex
Li, Yabo,Wang, Jingran,Huang, Mengmeng,Wang, Zhiwei,Wu, Yusheng,Wu, Yangjie
, p. 2890 - 2897 (2014/05/06)
An efficient phosphine-free direct C-H arylation of thiophenes at the α-position has been developed at low catalyst loading of bis(alkoxo)palladium complex (Cat.I, 0.1-0.2 mol %). The developed synthetic method can be applied to the synthesis of α-aryl/heteroaryl thiophenes from aryl or heteroaryl bromides in good to excellent yields and is compatible with the substrates bearing electron-donating or electron-withdrawing groups. The reactivities of the 2- and 5-positions of thiophenes are equivalent and not dependent on steric hindrance under optimal conditions. This condition can also be applied to other heterocyclic moieties such as benzothiophene, benzofuran, and pyrrole with high conversion yields.
