3419-91-8Relevant articles and documents
Copper-Catalyzed Aerobic Oxidation of N-Pyridylindole Leading to Fused Quinazolinones
Ye, Yaqing,Yue, Yuanyuan,Guo, Xiaohui,Chao, Junli,Yang, Yan,Sun, Chunying,Lv, Qingzhang,Liu, Jianming
, p. 3721 - 3725 (2021)
Copper catalyzed aerobic oxidation enables the tandem selective and efficient transformation of N-pyridylindole for the construction of 11H-pyrido[2,1-b]quinazolin-11-ones. The reaction shows good efficiency to accomplish the aerobic oxidation. Mechanisti
Elucidating the Mechanism of Aryl Aminations Mediated by NHC-Supported Nickel Complexes: Evidence for a Nonradical Ni(0)/Ni(II) Pathway
Rull, Silvia G.,Funes-Ardoiz, Ignacio,Maya, Celia,Maseras, Feliu,Fructos, Manuel R.,Belderrain, Tomás R.,Nicasio, M. Carmen
, p. 3733 - 3742 (2018)
Nickel catalysis is gaining in popularity in recent years, mostly within the area of cross-coupling. However, unlike Pd, the mechanisms of Ni-catalyzed C-C and C-heteroatom bond forming reactions have been much less studied, in particular when N-heterocyclic carbenes are used as ligands. Here, we present a thorough study of the mechanism of C-N cross-coupling reactions catalyzed by an NHC-Ni complex. Focusing on the coupling of 2-chloropyridines with indole catalyzed by [(IPrNi(styrene)2] (IPr = N,N′-bis(2,6-diisopropylphenyl)imidazol-2-ylidene), we have examined each of the elementary steps: i.e., oxidative addition, ligand substitution, and reductive elimination. All relevant catalytic intermediates have been isolated and structurally characterized by both spectroscopic and crystallographic methods. Kinetic studies have revealed that the reductive elimination is the rate-limiting step. Catalyst deactivation is related to the formation of unproductive dinuclear pyridyl-bridged NHC-NiII species, which can be prevented by increasing the size of the heteroaryl chloride. These investigations support a neutral Ni(0)/Ni(II) catalytic cycle. Calculations corroborate the experimental evidence and confirm the influence exerted by the ligands in each of the elementary steps.
Controlling selectivity in N-heterocycle directed borylation of indoles
Iqbal,Yuan,Cid,Pahl,Ingleson
, p. 2949 - 2958 (2021)
Electrophilic borylation of indoles with BX3(X = Cl or Br) using directing groups installed at N1 can proceed at the C2 or the C7 position. The six membered heterocycle directing groups utilised herein, pyridines and pyrimidine, result in indole C2 borylation being the dominant outcome (in the absence of a C2-substituent). In contrast, C7 borylation was achieved using five membered heterocycle directing groups, such as thiazole and benzoxazole. Calculations on the borylation of indole substituted with a five (thiazole) and a six (pyrimidine) membered heterocycle directing group indicated that borylation proceedsviaborenium cations with arenium cation formation having the highest barrier in both cases. The C7 borylated isomer was calculated to be the thermodynamically favoured product with both five and six membered heterocycle directing groups, but for pyrimidine directed indole borylation the C2 product was calculated to be the kinetic product. This is in contrast to thiazole directed indole borylation with BCl3where the C7 borylated isomer is the kinetic product too. Thus, heterocycle ring size is a useful way to control C2vs. C7 selectivity in N-heterocycle directed indole C-H borylation.
Ir(I)-Catalyzed C?H Glycosylation for Synthesis of 2-Indolyl-C-Deoxyglycosides
Yu, Changyue,Liu, Yichu,Xie, Xiong,Hu, Shulei,Zhang, Shurui,Zeng, Mingjie,Zhang, Dan,Wang, Jiang,Liu, Hong
supporting information, p. 4926 - 4931 (2021/09/09)
The construction of 2-deoxy-C-glycosides has gradually become a hotspot of carbohydrate chemistry in recent years. In this work, we present an efficient, regioselective, stereoselective and widely applicable strategy for the synthesis of 2-indolyl-C-deoxyglycosides via Ir(I)-catalyzed, pyridine-group-directed C?H functionalization. This method exhibits high tolerance for the functional groups of indoles and the protecting groups of carbohydrates. Moreover, this protocol has good stereoselectivity and mainly produces β-configuration products. Gram-scale synthesis and several practical transformations were conducted for further applications. Meantime, we also explored the mechanism of this method and proposed a catalytic cycle. (Figure presented.).
Cp?Co(III)-Catalyzed enantioselective hydroarylation of unactivated terminal alkenes via C-H activation
Fan, Jun,Hong, Xin,Liu, Lei,Liu, Yan-Hua,Shi, Bing-Feng,Xie, Pei-Pei,Zhang, Zhuo-Zhuo
supporting information, p. 19112 - 19120 (2021/11/26)
Enantioselective hydroarylation of unactivated terminal akenes constitutes a prominent challenge in organic chemistry. Herein, we reported a Cp*Co(III)-catalyzed asymmetric hydroarylation of unactivated aliphatic terminal alkenes assisted by a new type of tailor-made amino acid ligands. Critical to the chiral induction was the engaging of a novel noncovalent interaction (NCI), which has seldomly been disclosed in the C-H activation area, arising from the molecular recognition among the organocobalt(III) intermediate, the coordinated alkene, and the well-designed chiral ligand. A broad range of C2-alkylated indoles were obtained in high yields and excellent enantioselectivities. DFT calculations revealed the reaction mechanism and elucidated the origins of chiral induction in the stereodetermining alkene insertion step.
