1421276-52-9Relevant academic research and scientific papers
Tosyl Hydrazine-Promoted Tandem Condensation and Cyclization of Acyl Azobenzenes Enabling Access to 2H-Indazoles under Metal-Free Aerobic Conditions
Son, Jeong-Yu,Kim, Hyunseok,Baek, Yonghyeon,Um, Kyusik,Ko, Gi Hoon,Han, Gi Uk,Han, Sang Hoon,Lee, Kooyeon,Lee, Phil Ho
, p. 4354 - 4361 (2018/10/02)
Tosyl hydrazine-promoted tandem condensation and cyclization of 2-acyl azobenzenes under metal-free aerobic conditions was demonstrated to give 2-aryl-2H-indazoles having alkyl- or aryl groups at the 3-position in quantitative yields through the release o
Rh(III)-Catalyzed [4 + 1]-Annulation of Azoxy Compounds with Alkynes: A Regioselective Approach to 2H-Indazoles
Long, Zhen,Yang, Yudong,You, Jingsong
supporting information, p. 2781 - 2784 (2017/06/07)
A rhodium-catalyzed regioselective C-H activation/cyclization of azoxy compounds with alkynes has been disclosed to construct a variety of 2H-indazoles. A [4 + 1]-cycloaddition rather than a normal [4 + 2] mode is observed in the process of cyclative capture along with an oxygen-atom transfer and a C≡C triple bond cleavage. This protocol features a broad substrate scope, a good functional group tolerance, and an exclusive regioselectivity.
Rhenium-Catalyzed [4 + 1] Annulation of Azobenzenes and Aldehydes via Isolable Cyclic Rhenium(I) Complexes
Geng, Xiaoyu,Wang, Congyang
supporting information, p. 2434 - 2437 (2015/05/27)
The first Re-catalyzed [4 + 1] annulation of azobenzenes with aldehydes was developed to furnish 2H-indazoles via isolable and characterized cyclic ReI-complexes. For the first time, the acetate-acceleration effect is showcased in Re-catalyzed C-H activation reactions. Remarkably, mechanistic studies revealed an irreversible aldehyde-insertion step, which is in sharp contrast to those of previous Rh- and Co-systems. (Chemical Presented).
Cobalt(III)-catalyzed synthesis of indazoles and furans by C-H bond functionalization/addition/cyclization cascades
Hummel, Joshua R.,Ellman, Jonathan A.
supporting information, p. 490 - 498 (2015/01/30)
The development of operationally straightforward and cost-effective routes for the assembly of heterocycles from simple inputs is important for many scientific endeavors, including pharmaceutical, agrochemical, and materials research. In this article we describe the development of a new air-stable cationic Co(III) catalyst for convergent, one-step benchtop syntheses of N-aryl-2H-indazoles and furans by C-H bond additions to aldehydes followed by in situ cyclization and aromatization. Only a substoichiometric amount of AcOH is required as an additive that is both low-cost and convenient to handle. The syntheses of these heterocycles are the first examples of Co(III)-catalyzed additions to aldehydes, and reactions are demonstrated for a variety of aromatic, heteroaromatic, and aliphatic derivatives. The syntheses of both N-aryl-2H-indazoles and furans have been performed on 20 mmol scales and should be readily applicable to larger scales. The reported heterocycle syntheses also demonstrate the use of directing groups that have not previously been applied to Co(III)-catalyzed C-H bond functionalizations. Additionally, the synthesis of furans demonstrates the first example of Co(III)-catalyzed functionalization of alkenyl C-H bonds.
Direct access to acylated azobenzenes via Pd-catalyzed C-H functionalization and further transformation into an indazole backbone
Li, Hongji,Li, Pinhua,Wang, Lei
, p. 620 - 623 (2013/04/10)
Azobenzenes were readily acylated at the 2-position through a Pd-catalyzed C-H functionalization from simple aromatic azo compounds and aldehydes in good yields. The obtained acylated azobenzenes could be efficiently converted into the corresponding indaz
