94191-74-9Relevant articles and documents
Ir-Catalyzed Ligand-Free Directed C-H Borylation of Arenes and Pharmaceuticals: Detailed Mechanistic Understanding
Mahamudul Hassan, Mirja Md,Mondal, Biplab,Singh, Sukriti,Haldar, Chabush,Chaturvedi, Jagriti,Bisht, Ranjana,Sunoj, Raghavan B.,Chattopadhyay, Buddhadeb
, p. 4360 - 4375 (2022/03/16)
An efficient method for Ir-catalyzed ligand free ortho borylation of arenes (such as, 2-phenoxypyridines, 2-anilinopyridines, benzylamines, benzylpiperazines, benzylmorpholines, benzylpyrrolidine, benzylpiperidines, benzylazepanes, α-amino acid derivatives, aminophenylethane derivatives, and other important scaffolds) and pharmaceuticals has been developed. The reaction underwent via an interesting mechanistic pathway, as revealed by the detailed mechanistic investigations by using kinetic isotope studies and DFT calculations. The catalytic cycle is found to involve the intermediacy of an Ir-boryl complex where the substrate C-H activation is the turnover determining step, intriguingly without any appreciable primary KIE. The method displays a broad range of substrate scope and functional group tolerance. Numerous late-stage borylation of various important molecules and drugs were achieved using this developed strategy. The borylated compounds were further converted into more valuable functionalities. Moreover, utilizing the benefit of the B-N intramolecular interaction of the mono borylated compounds, an operationally simple method has been developed for the selective diborylation of 2-phenoxypyridines and numerous functionalized arenes. Furthermore, the synthetic utility has been showcased with the removal of the pyridyl directing group from the borylated product to achieve ortho borylated phenol along with the ipso-borylation for the preparation of 1,2-diborylated benzene.
Substituent Effects of 2-Pyridones on Selective O-Arylation with Diaryliodonium Salts: Synthesis of 2-Aryloxypyridines under Transition-Metal-Free Conditions
Li, Xiao-Hua,Ye, Ai-Hui,Liang, Cui,Mo, Dong-Liang
, p. 1699 - 1710 (2018/02/06)
An efficient transition-metal-free strategy to synthesize 2-aryloxypyridine derivatives has been developed by a selective O-arylation of 2-pyridones with diaryliodonium salts. The reaction was compatible with a series of functional groups for 2-pyridones and diaryliodonium salts such as halides, nitro, cyano, and ester groups. The substituents at the C6-position of 2-pyridones favored O-arylation products because of steric hindrance. The reaction was easily performed on a gram-scale and 6-chloro-2-pyridone was a good precursor to access various unsubstituted 2-aryloxypyridines by dehalogenation. A P2Y 1 lead compound analogue could be prepared in good yield over two steps.
Palladium-catalyzed direct ortho aroylation of 2-phenoxypyridines with aldehydes and catalytic mechanism investigation
Chu, Jean-Ho,Chen, Shih-Tien,Chiang, Meng-Fan,Wu, Ming-Jung
supporting information, p. 953 - 966 (2015/03/18)
A direct ortho aroylation of 2-phenoxypyridines with aldehydes leading to aryl ketones by the use of palladium(II) acetate, tert-butyl hydroperoxide, and chlorobenzene as the catalyst, oxidant, and solvent, respectively, is presented. Intra- and intermolecular kinetic isotope effects, radical trapping, and controlled experiments were carried out to support the proposed catalytic mechanism for the reaction. Syntheses of (2-hydroxyphenyl)(phenyl)methanones and 1-hydroxy-9H-fluoren-9-ones directed from ortho-aroylated 2-phenoxypyridines were demonstrated.
