43120-26-9Relevant articles and documents
Regioselective C3-H Trifluoromethylation of 2 H-Indazole under Transition-Metal-Free Photoredox Catalysis
Murugan, Arumugavel,Babu, Venkata Nagarjuna,Polu, Ashok,Sabarinathan, Nagaraj,Bakthadoss, Manickam,Sharada, Duddu S.
, p. 7796 - 7803 (2019/06/27)
Trifluoromethyl-substituted heteroarenes are biologically active compounds and useful building blocks. In this sequence, we have developed a visible-light-promoted regioselective C3-H trifluoromethylation of 2H-indazole under metal-free conditions, which
A General One-Pot Synthesis of 2H-Indazoles Using an Organophosphorus–Silane System
Schoene, Jens,Bel Abed, Hassen,Schmieder, Peter,Christmann, Mathias,Nazaré, Marc
supporting information, p. 9090 - 9100 (2018/06/29)
A simple and direct approach for the regioselective construction of the privileged 2H-indazole scaffold is described. The developed one-pot strategy involves phospholene-mediated N?N bond formation to access 2H-indazoles. The amount of organophosphorus reagent was minimized by recycling the phospholene oxide with organosilane reductants. Starting from functionalized 2-nitrobenzaldehydes and primary amines, a mild reductive cyclization, involving the use of commercially available phospholene oxide and silanes, delivered a wide variety of substituted 2H-indazoles in good to excellent yields.
A Biphilic Phosphetane Catalyzes N-N Bond-Forming Cadogan Heterocyclization via PIII/PV = O Redox Cycling
Nykaza, Trevor V.,Harrison, Tyler S.,Ghosh, Avipsa,Putnik, Rachel A.,Radosevich, Alexander T.
, p. 6839 - 6842 (2017/05/29)
A small-ring phosphacycle, 1,2,2,3,4,4-hexamethylphosphetane, is found to catalyze deoxygenative N-N bond-forming Cadogan heterocyclization of o-nitrobenzaldimines, o-nitroazobenzenes, and related substrates in the presence of hydrosilane terminal reductant. The reaction provides a chemoselective catalytic synthesis of 2H-indazoles, 2H-benzotriazoles, and related fused heterocyclic systems with good functional group compatibility. On the basis of both stoichiometric and catalytic mechanistic experiments, the reaction is proposed to proceed via catalytic PIII/PV = O cycling, where DFT modeling suggests a turnover-limiting (3+1) cheletropic addition between the phosphetane catalyst and nitroarene substrate. Strain/distortion analysis of the (3+1) transition structure highlights the controlling role of frontier orbital effects underpinning the catalytic performance of the phosphetane.
