Rh(III)-Catalyzed [4 + 1]-Annulation of Azoxy Compounds with Alkynes: A Regioselective Approach to 2<i>H</i>-Indazoles
作者:Zhen Long、Yudong Yang、Jingsong You
DOI:10.1021/acs.orglett.7b00982
日期:2017.6.2
A rhodium-catalyzed regioselective C–H activation/cyclization of azoxycompounds 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
Visible light-promoted, photocatalyst-free decarboxylative alkylation of 2<i>H</i>-indazoles <i>via</i> electron donor–acceptor complex activation
作者:Jin Wang、Qingyuan Song、Xing He、Chunhua Ma、Yuqin Jiang、Jing Fan
DOI:10.1039/d2nj02766f
日期:——
A transition metal-free and traditional dye-free visible light-driven direct alkylation of 2-aryl-2H-indazoles was developed in the catalytic system of an electrondonor–acceptor (EDA) complex involving alkyl N-hydroxyphthalimide (NHPI) esters, triphenylphosphine (PPh3), and sodium iodide (NaI).
Facile synthesis of 2H-indazole derivatives starting from the Baylis–Hillman adducts of 2-cyclohexen-1-one
作者:Ka Young Lee、Saravanan Gowrisankar、Jae Nyoung Kim
DOI:10.1016/j.tetlet.2005.05.149
日期:2005.8
Facile synthetic method of 2H-indazole derivatives was developed involving DDQ oxidation of pyrazoles, which were prepared starting from the Baylis-Hillman adducts of 2-cyclohexen-1-one. (c) 2005 Elsevier Ltd. All rights reserved.
CN114989089
申请人:——
公开号:——
公开(公告)日:——
Rhenium-Catalyzed [4 + 1] Annulation of Azobenzenes and Aldehydes via Isolable Cyclic Rhenium(I) Complexes
作者:Xiaoyu Geng、Congyang Wang
DOI:10.1021/acs.orglett.5b00938
日期:2015.5.15
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-