1239-56-1Relevant academic research and scientific papers
Fulvene Synthesis by Rhodium(I)-Catalyzed [2+2+1] Cycloaddition: Synthesis and Catalytic Activity of Tunable Cyclopentadienyl Rhodium(III) Complexes with Pendant Amides
Yoshizaki, Soichi,Shibata, Yu,Tanaka, Ken
, p. 3590 - 3593 (2017)
It has been established that a RhI+/segphos complex catalyzes the [2+2+1] cycloaddition of 1,6-diynes with cyclopropylideneacetamides to give substituted fulvenes in good yields. The reductive complexation of the product fulvenes with RhCl3 in EtOH furnished the corresponding dinuclear cyclopentadienyl RhIII complexes bearing a pendant amide moiety. These RhIII complexes were highly active catalysts for oxidative annulation and cyclization through C(sp2)?H and C(sp3)?H functionalization.
Rhodium-Catalyzed Annulation of N-Acetoxyacetanilide with Substituted Alkynes: Conversion of Nitroarenes to Substituted Indoles
Ghorai, Jayanta,Ramachandran, Kuppan,Anbarasan, Pazhamalai
, p. 14812 - 14825 (2021/10/25)
A general and efficient rhodium-catalyzed redox-neutral annulation of N-acetoxyacetanilides, readily accessible from nitroarenes, with alkynes has been accomplished for the synthesis of substituted indole derivatives. A wide range of substituted 2,3-diarylindoles were achieved from various substituted N-acetoxyacetanilides and symmetrical/unsymmetrical alkynes in good to excellent yields. The developed method was successfully integrated with the synthesis of N-acetoxyacetanilides for the efficient one-pot synthesis of indoles from nitroarenes. The important features are the introduction of N-acetoxyacetamide as a new directing group, redox-neutral annulation, an additive-free approach, wide functional group tolerance, an intramolecular version, and a one-pot reaction of nitroarenes. The method was further extended to the synthesis of potent higher analogues of indole, viz., pyrrolo[3,2-f]indoles and dibenzo[a,c]carbazoles. In addition, a plausible mechanism was proposed based on the isolation and stoichiometric study of a potential aryl-Rh intermediate.
Mild and efficient synthesis of indoles and isoquinolones via a nickel-catalyzed Larock-type heteroannulation reaction
Weng, Wei-Zhi,Xie, Jian,Zhang, Bo
supporting information, p. 3983 - 3988 (2018/06/08)
A simple and efficient approach for the preparation of substituted indoles and isoquinolones via a nickel-catalyzed Larock-type heteroannulation reaction is reported. This transformation employed air-stable and inexpensive Ni(dppp)Cl2 as a precatalyst and Et3N as a mild base. Moreover, the reaction occurs efficiently under mild conditions, and a wide range of substituted indoles and isoquinolones bearing various functional groups are obtained in moderate to excellent yields.
Synthesis of Functionalized (η5-Indenyl)rhodium(III) Complexes and Their Application to C?H Bond Functionalization
Terasawa, Jyunichi,Shibata, Yu,Kimura, Yuki,Tanaka, Ken
supporting information, p. 505 - 509 (2018/03/06)
It has been established that reductive complexation of functionalized benzofulvenes, which are readily prepared from commercially available indene and 2-methylindene, with RhCl3 in ethanol affords the corresponding indenyl–rhodium(III) dichlorides bearing substituents at the 1- (H or CO2Et), 2- (H or Me), and 3- [CH2Ph or CH2(2-MeOC6H4)] positions. The indenyl–rhodium(III) complexes bearing one ethoxycarbonyl group showed higher thermal stability and regioselectivity than our previously reported CpERhIII complex toward the oxidative [3+2] annulation of acetanilides with internal alkynes.
Mechanochemical Ruthenium-Catalyzed Hydroarylations of Alkynes under Ball-Milling Conditions
Cheng, Hanchao,Hernández, José G.,Bolm, Carsten
supporting information, p. 6284 - 6287 (2017/12/08)
Under solventless grinding conditions, mechanochemical ruthenium-catalyzed hydroarylations of alkynes with acetanilides lead to trisubstituted alkenes. Only catalytic amounts of pivalic acid or copper acetate are required, and without the need for externa
Mechanochemical indole synthesis by rhodium-catalysed oxidative coupling of acetanilides and alkynes under solventless conditions in a ball mill
Hermann, Gary N.,Jung, Celine L.,Bolm, Carsten
supporting information, p. 2520 - 2523 (2017/07/17)
A mechanochemical indole synthesis by rhodium(iii)-catalysed C-H bond functionalisation in a planetary mill has been developed. It occurs in the absence of any solvent, does not require additional heating and only needs catalytic quantities of Cu(OAc)2 in combination with dioxygen as a terminal oxidant. Accordingly, the process represents a powerful and environmentally benign alternative to the common solution-based standard protocols.
Rhodium-Catalyzed Oxidative Benzannulation of N-Pivaloylanilines with Internal Alkynes through Dual C?H Bond Activation: Synthesis of Highly Substituted Naphthalenes
Zhang, Xuan,Yu, Xiaoqiang,Feng, Xiujuan,Yamamoto, Yoshinori,Almansour, Abdulrahman I.,Arumugam, Natarajan,Kumar, Raju Suresh,Bao, Ming
, p. 3241 - 3250 (2016/11/28)
An efficient method was developed for the synthesis of highly substituted naphthalenes through rhodium-catalyzed oxidative benzannulation of N-pivaloylanilines with internal alkynes. The benzannulation reaction proceeded smoothly through dual C?H bond act
Control over Organometallic Intermediate Enables Cp?Co(III) Catalyzed Switchable Cyclization to Quinolines and Indoles
Lu, Qingquan,Vásquez-Céspedes, Suhelen,Gensch, Tobias,Glorius, Frank
, p. 2352 - 2356 (2016/04/26)
Achieving controllable C-H functionalization to elaborate valuable compounds from simple chemicals is attractive and highly desirable, especially if nonprecious transition metal catalysts can be used. However, controlling selectivity in these transformations remains a continuous challenge to synthetic chemists. Herein, we show for the first time that control over the reactive organometallic intermediate enables the switchable synthesis of quinoline and indole from amides and alkynes through C-H activation using Cp?Co(III). The keys to this strategy are (1) introducing a Lewis acid to greatly accelerate the dehydrative cyclization, which can outcompete dehydrogenative cyclization, and (2) tuning the directing group to facilitate the dehydrogenative cyclization and inhibit dehydrative cyclization.
Indole Synthesis via Cobalt(III)-Catalyzed Oxidative Coupling of N-Arylureas and Internal Alkynes
Zhang, Zhuo-Zhuo,Liu, Bin,Xu, Jing-Wen,Yan, Sheng-Yi,Shi, Bing-Feng
supporting information, p. 1776 - 1779 (2016/05/19)
A mild Co(III)-catalyzed oxidative annulation of N-arylureas and internal alkynes has been developed. The use of less electrophilic ureas other than acetamides as directing groups is crucial for the reaction. A broad range of synthetically useful functional groups are compatible with this reaction, thus providing a new opportunity for the synthesis of diverse indoles.
Synthesis of indoles and polycyclic amides via ruthenium(ii)-catalyzed C-H activation and annulation
Lin, Hui,Li, Shuai-Shuai,Dong, Lin
supporting information, p. 11228 - 11234 (2015/11/27)
Ruthenium(ii)-catalyzed oxidative coupling of NH protic amides with alkynes has been developed for the synthesis of a diversity of complex structures, such as N-acyl indole and tricyclic amide derivatives.
