2325-27-1Relevant articles and documents
Reactivity of N phenyl iminophosphoranes towards ozone: Evidence of trioxo azaphospholane intermediates
El Khatib, Fayez,Bellan, Jacques,Koenig, Max
, p. 391 - 398 (1998)
The ozonation of N-phenyl-iminophosphoranes R3P=NPh 1a-b leads, after the P-N bond breakage, to the corresponding phosphorus oxides 2a-b with the formation of complex adducts 3a-b which precipitate at room temperature. The stoichiometry and the reaction mechanism depend on the nature of substituents R linked to the phosphorus atom. For R=Ph we detected the phosphonium intermediate 5a, whereas for R=OEt the trioxoazaphospholanes 7b-9b were characterized by 31P NMR.
A new synthetic utility of iminophosphoranes. Synthesis of trifluoromethylated enamino and imino esters
Shen, Yanchang,Gao, Shu
, p. 37 - 39 (1996)
A new synthetic utility of iminophosphoranes, including the reaction of iminophosphoranes with trifluoroacetic anhydride and organozinc compounds, to afford trifluoromethylated amino and imino esters is described.
Metal-free deoxygenation and reductive disilylation of nitroarenes by organosilicon reducing reagents
Bhattacharjee, Argha,Hosoya, Hiromu,Ikeda, Hideaki,Nishi, Kohei,Tsurugi, Hayato,Mashima, Kazushi
, p. 11278 - 11282 (2018/10/20)
A metal-free deoxygenation and reductive disilylation of nitroarenes was achieved using N,N’-bis(trime-thylsilyl)-4,4’-bipyridinylidene (1) under mild and neutral reaction conditions, and a broad functional group tolerance was possible in this reaction. Mono-deoxygenation, giving a synthetically valuable N,O-bis(trimethylsilyl)phe-nylhydroxylamine (7a) as a readily available and safe phenylnitrene source from nitrobenzene, and double-deoxy-genation, giving N,N-bis(trimethylsilyl)anilines 8, were easily controlled by varying the amounts of 1 and reaction temperature as well as adding dibenzothiophene (DBTP). Reaction of 2-arylnitrobenzenes with 1 resulted in the formation of the corresponding carbazoles 14 via in situ-gen-erated phenylnitrene species derived by thermolysis of N,O-bis(trimethylsilyl)phenylhydroxylamines 7, followed by their subsequent intramolecular C H insertion. In addition, the intramolecular N N coupling reaction proceeded in the reduction of 2,2’-dinitrobiphenyl derivatives by 1, giving the corresponding benzo[c]cinnolines.
Preparation of 1,2,5-Trisubstituted 1H-Imidazoles from Ketenimines and Propargylic Amines by Silver-Catalyzed or Iodine-Promoted Electrophilic Cyclization Reaction of Alkynes
Zhou, Xiaorong,Jiang, Zheng,Xue, Lexing,Lu, Ping,Wang, Yanguang
, p. 5789 - 5797 (2015/09/15)
From readily available propargylic amines, 1,2,5-trisubstituted imidazoles are efficiently obtained through a cascade reaction catalyzed by AgOTf or promoted by molecular iodine. The AgOTf-catalyzed reaction involves nucleophilic addition of propargylic amine to ketenimine, a silver-catalyzed electrophilic cyclization reaction of alkyne, and a tautomerism/isomerism/metal-H exchange cascade. The iodine-mediated counterpart yields 5-formyl-1,2-disubtituted imidazoles, which presumably includes a cascade hydrolysis/oxidation reaction. Furthermore, the presented protocol can be scaled up and the resultant 1,2,5-trisubstituted imidazole can be converted into fused indeno[1,2-d]imidazole. 1,2,5-Trisubstituted imidazoles are efficiently prepared from readily available propargylic amines through a AgOTf-catalyzed or molecular iodine-promoted cascade reaction. The presented protocol can be scaled up and the resultant 1,2,5-trisubstituted imidazoles can be converted into fused indeno[1,2-d]imidazoles.
Kinetics and mechanism of the nitrosobenzene deoxygenation by trivalent phosphorous compounds
Khursan,Shamukaev,Chainikova,Khursan,Safiullin
, p. 2477 - 2486 (2014/11/08)
The reaction of aryl nitroso compounds with organic phosphines and phosphites in aerated media is a convenient non-photolytic procedure to generate aromatic nitroso oxides. The reaction rate constants and activation parameters of the key (for the proposed method of nitroso oxide generation) reaction of nitrosobenzene with tripenyl phosphite or para-substituted phosphines (4-RC 6H4)3P (R = MeO, Me, H, F), as well as that of para-methoxynitrosobenzene with triphenylphosphine in acetonitrile were determined by kinetic spectrophotometry and chemiluminescence. A significant transfer of the electron density to the nitroso compound occurs in the transition state of the reaction as was revealed using the Hammett correlation analysis and DFT calculations in the M06L/6-311+G(d,p) approximation. The introduction of the electron-donor substituent MeO into the para-position of PhNO decreases the reactivity of the nitroso compound by two orders of magnitude. The reactivity of triphenyl phosphite in the oxygen atom transfer reaction is lower by two orders of magnitude compared to that of triphenylphosphine. In the case of the reactions of PhNO with phosphines, the apparent rate constant depends on the oxygen content in the reaction medium.
Synthesis of 4-fluoromethylsydnones and their participation in alkyne cycloaddition reactions
Foster, Robert S.,Adams, Harry,Jakobi, Harald,Harrity, Joseph P. A.
, p. 4049 - 4064 (2013/06/05)
We report the synthesis and some structural studies of 4-trifluoromethyl, 4-difluoromethyl-, and 4-monofluoromethylsydnones. All but the latter compounds are stable and represent effective precursors to a range of pyrazoles after cycloaddition reactions with alkynes. The cycloadditions are generally highly regioselective and provide 5-fluoromethylpyrazole products, although we have observed that Bn-substituted sydnones can provide an unexpected alkyne insertion mode that generates the 3-fluoromethyl isomer.
Phosphinimine-borane combinations in frustrated Lewis pair chemistry
Jiang, Chunfang,Stephan, Douglas W.
, p. 630 - 637 (2013/02/23)
The phosphinimines Ph3PNR (R = Ph 1, C6F 52, tBu 3) are combined with B(C6F5) 3 in an effort to explore the frustrated Lewis pair (FLP) chemistry. While compound 1 is shown to form an adduc
A general and regioselective synthesis of 5-trifluoromethyl-pyrazoles
Foster, Robert S.,Harrity, Joseph P. A.,Jakobi, Harald
supporting information, p. 4858 - 4861,4 (2012/12/12)
Two synthetic approaches to 4-trifluoromethylsydnones, a novel class of these mesoionic reagents, are reported. These compounds undergo regioselective alkyne cycloaddition reactions, thereby providing a general approach to 5-trifluoromethylpyrazoles. This method has been employed in a short formal synthesis of the herbicide fluazolate.
Reaction between triphenylphosphine and aromatic amines in the presence of diethyl azodicarboxylate: An efficient synthesis of aryliminophosphoranes under neutral and mild conditions
Adib, Mehdi,Sheikhi, Ehsan,Deljoush, Azadeh
experimental part, p. 4137 - 4140 (2011/06/24)
An efficient synthesis of aryliminophosphoranes is described. A mixture of an aromatic amine, diethyl azodicarboxylate and triphenylphosphine undergo a Mitsonobu type reaction at ambient temperature in dry dichloromethane to afford aryliminophosphoranes in excellent yields.
Copper(II) acetate/oxygen-mediated nucleophilic addition and intramolecular C-H activation/C-N or C-C bond formation: One-pot synthesis of benzimidazoles or quinazolines
He, Hua-Feng,Wang, Zhi-Jing,Bao, Weiliang
supporting information; experimental part, p. 2905 - 2912 (2010/12/29)
Diarylcarbodiimides or benzylphenylcarbodiimides are converted to 1,2-disubstituted benzimidazoles or 1,2-disustituted quinazolines via addition/intramolecular C-H bond activation/C-N or C-C bond forming reaction using copper(II) acetate/oxygen [Cu(OAc)2/O2] as the oxidant at 100°C in one-pot cascade procedure. Copyright
