2467-83-6Relevant articles and documents
Biphilic Organophosphorus-Catalyzed Intramolecular Csp2-H Amination: Evidence for a Nitrenoid in Catalytic Cadogan Cyclizations
Nykaza, Trevor V.,Ramirez, Antonio,Harrison, Tyler S.,Luzung, Michael R.,Radosevich, Alexander T.
, p. 3103 - 3113 (2018/03/08)
A small-ring phosphacycloalkane (1,2,2,3,4,4-hexamethylphosphetane, 3) catalyzes intramolecular C-N bond forming heterocyclization of o-nitrobiaryl and -styrenyl derivatives in the presence of a hydrosilane terminal reductant. The method provides scalable access to diverse carbazole and indole compounds under operationally trivial homogeneous organocatalytic conditions, as demonstrated by 17 examples conducted on 1 g scale. In situ NMR reaction monitoring studies support a mechanism involving catalytic PIII/PV=O cycling, where tricoordinate phosphorus compound 3 represents the catalytic resting state. For the catalytic conversion of o-nitrobiphenyl to carbazole, the kinetic reaction order was determined for phosphetane catalyst 3 (first order), substrate (first order), and phenylsilane (zeroth order). For differentially 5-substituted 2-nitrobiphenyls, the transformation is accelerated by electron-withdrawing substituents (Hammett factor ? = +1.5), consistent with the accrual of negative charge on the nitro substrate in the rate-determining step. DFT modeling of the turnover-limiting deoxygenation event implicates a rate-determining (3 + 1) cheletropic addition between the phosphetane catalyst 3 and 2-nitrobiphenyl substrate to form an unobserved pentacoordinate spiro-bicyclic dioxazaphosphetane, which decomposes via (2 + 2) cycloreversion giving 1 equiv of phosphetane P-oxide 3·[O] and 2-nitrosobiphenyl. Experimental and computational investigations into the C-N bond forming event suggest the involvement of an oxazaphosphirane (2 + 1) adduct between 3 and 2-nitrosobiphenyl, which evolves through loss of phosphetane P-oxide 3·[O] to give the observed carbazole product via C-H insertion in a nitrene-like fashion.
Rh(I)-catalyzed decarbonylation synthesis of carbazoles via C-N cleavage
Fan, Weizheng,Jiang, Shan,Feng, Bainian
, p. 4035 - 4038 (2015/06/02)
A one-pot Rh(I)-catalyzed synthesis of 9-H carbazoles via C-N bond cleavage by activation of aldehyde C-H bonds is reported. This protocol offers good yields and tolerates a broad range of functional groups. Based on the extensive control experiments, we propose a plausible decarbonylation mechanism.
Direct synthesis of N -H carbazoles via iridium(III)-catalyzed intramolecular C-H amination
Suzuki, Chiharu,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
, p. 1597 - 1600 (2015/03/30)
The iridium-catalyzed dehydrogenative cyclization of 2-aminobiphenyls proceeds smoothly in the presence of a copper cocatalyst under air as a terminal oxidant through intramolecular direct C-H amination to produce N-H carbazoles. A similar iridium/copper system can also catalyze the unprecedented dimerization reaction of 2-aminobiphenyl involving 2-fold C-H/N-H couplings.
"transition-metal-free" synthesis of carbazoles by photostimulated reactions of 2′-halo[1,1′-biphenyl]-2-amines
Guerra, Walter D.,Rossi, Roberto A.,Pierini, Adriana B.,Barolo, Silvia M.
, p. 928 - 941 (2015/01/30)
An efficient and simple protocol for the preparation of a series of 9H-carbazoles by photostimulated SRN1 substitution reactions is presented. Substituted 9H-carbazoles were synthesized in low to excellent yields (up to 96%) through an intramolecular C-N bond formation of 2′-halo[1,1′-biphenyl]-2-amines by the photoinitiated SRN1 mechanism under mild and "transition-metal-free" conditions. The biphenylamines used as substrates were obtained with isolated yields ranging from 21% to 84% by two approaches: (A) the cross-coupling Suzuki-Miyaura reaction and (B) the radical arylation of anilines. Some key aspects of the proposed mechanism were evaluated at the B3LYP/6-311+G? level.
Synthesis of carbazoles by copper-catalyzed intramolecular C-H/N-H coupling
Takamatsu, Kazutaka,Hirano, Koji,Satoh, Tetsuya,Miura, Masahiro
, p. 2892 - 2895 (2014/06/23)
A Cu-catalyzed intramolecular C-H amination for the synthesis of carbazoles has been developed. The key to success is the installation of the picolinamide-based directing group, which is spontaneously removed after the coupling event. The Cu catalysis proceeded smoothly under Pd- and I(III)-free conditions, and its mild oxidation aptitude enables the rapid and concise construction of heteroatom-incorporated carbazole core π-systems.
Amino-directed RhIII-catalyzed C-H activation leading to one-pot synthesis of N-H carbazoles
Jiang, Qibai,Duan-Mu, Dandan,Zhong, Wei,Chen, Hao,Yan, Hong
supporting information, p. 1903 - 1907 (2013/03/28)
One-pot synthesis: An efficient amino-directed one-pot synthesis of N-H carbazoles from unprotected 2-aminobiaryl compounds is reported. The free amino unit acts as both a directing group for ortho C-H activation and a functional group for construction of an N-heterocyclic ring (see scheme). Copyright
Kinesin spindle protein (KSP) inhibitors with 2,3-fused indole scaffolds
Oishi, Shinya,Watanabe, Toshiaki,Sawada, Jun-Ichi,Asai, Akira,Ohno, Hiroaki,Fujii, Nobutaka
experimental part, p. 5054 - 5058 (2010/09/05)
Mitotic kinesin spindle protein (KSP) is involved in the assembly of the bipolar spindle during cell division. On the basis of a common 2,3-fused indole substructure within the complex frameworks of terpendole E and other KSP inhibitors, the carbazoles with a bulky alkyl group were identified as a novel KSP inhibitory scaffold. Additionally, among several naturally occurring cell growth inhibitors with 2,3-fused indole structures,β-carboline alkaloids, harman and harmine, showed moderate inhibition of KSP.
Methods and compositions
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Page/Page column 14, (2009/07/17)
Compounds, compositions and methods relating to kinesin inhibition are described herein.
Rh2(II)-catalyzed synthesis of carbazoles from biaryl azides
Stokes, Benjamin J.,Jovanovic, Brankica,Dong, Huijun,Richert, Kathleen J.,Riell, Ryan D.,Driver, Tom G.
supporting information; experimental part, p. 3225 - 3228 (2009/08/07)
An array of carbazoles (23 examples) can be synthesized from substituted biaryl azides at 60 °C using substoichio-metric quantities of Rh 2(O2CC3F7)4 or Rh 2(O2CC7H15)4.
Intramolecular Ir(I)-catalyzed benzylic C-H bond amination of ortho-substituted aryl azides
Sun, Ke,Sachwani, Rachna,Richert, Kathleen J.,Driver, Tom G.
scheme or table, p. 3598 - 3601 (2011/02/23)
Image Persented Iridium(I) catalyzes the intramolecular benzylic C-H bond amination of ortho-homobenzyl-substituted aryl azides to produce indolines at 25 °C.
