1232-40-2Relevant academic research and scientific papers
A simple, user-friendly process for the homologation of aldehydes using tosylhydrazone salts
Aggarwal, Varinder K.,De Vicente, Javier,Pelotier, Beatrice,Holmes, Ian P.,Bonnert, Roger V.
, p. 10327 - 10331 (2007/10/03)
Aldehydes can be homologated to ketones in moderate to good yields using aryldiazomethanes generated in situ from tosylhydrazones. Chiral aldehydes can be employed with almost complete retention of configuration. The tosylhydrazones can also be generated in situ from the corresponding aldehyde leading to a one-pot process for coupling two different carbonyl compounds to give ketones. (C) 2000 Elsevier Science Ltd.
A simple method for the synthesis of substituted benzylic ketones: Homologation of aldehydes via the in situ generation of aryldiazomethanes from aromatic aldehydes
Angle, Steven R.,Neitzel, Martin L.
, p. 6458 - 6461 (2007/10/03)
A general method for the homologation of aldehydes to benzylic ketones has been developed. Aryldiazomethanes were generated in situ in the presence of an aldehyde by simply heating the tosylhydrazones of aromatic aldehydes in the presence of a stoichiometric amount of base in polar protic solvents. The resulting polar protic solvent promoted homologation afforded benzylic ketones in moderate to excellent yields with a variety of aldehydes. Isolation of the tosylhydrazones was not necessary; they could be prepared in ethanol and carried through the sequence without isolation. This methodology allows easy access to a wide variety of substituted aryldiazomethanes that would be difficult, or even impossible, to prepare via conventional methods and circumvents the toxicity and stability problems associated with the isolation and/or handling solutions of aryldiazomethanes.
Intermolecular and intramolecular ketone-nitrile reductive coupling reactions promoted by TiCl4-Sm system
Zhou, Longhu,Zhang, Yongmin
, p. 2953 - 2960 (2007/10/03)
The intermolecular and intramolecular reductive coupling reactions of ketones with nitriles have been successfully promoted by low-valent titanium prepared by the TiCL4-Sm system. Substituted ketones, monocyclic α-amino alcohols and monocyclic amines composed of a number of substitution patterns have been prepared in good yields at room or THF reflux temperature under neutral conditions. The procedure can avoid over reduction of the resulting of ketones, α-amino alcohols or amines. The crystal structures of two monocyclic α-amino alcohols are reported. (C) 2000 Elsevier Science Ltd.
Supramolecular Steric Effects as the Means of Making Reactive Carbon Radicals Persistent. Quantitative Characterization of the External Surface of MFI Zeolites through a Persistent Radical Probe and a Langmuir Adsorption Isothez
Hirano, Takashi,Li, Wei,Abrams, Lloyd,Krusic, Paul J.,Ottaviani, M. Francesca,Turro, Nicholas J.
, p. 1319 - 1330 (2007/10/03)
The photochemistry of tetraphenylacetone (1) adsorbed on the external surface of a MFI zeolite (the sodium form of LZ-105) has been investigated in combination with computational chemistry, surface area measurements, EPR analysis, and classical adsorption isotherms. All of the methods are consistent with a supramolecular structural model in which 1 is first adsorbed strongly through intercalation of a single benzene ring into a hole on the LZ-105 external surface (site I) followed by a weaker binding to the external framework between the holes (site II) until a monolayer of 1 is formed. From both computational and surface area measurements, it is estimated that the site I holes on the external surface will be filled at ca. 0.3-0.5 wt %/wt loading of 1/LZ-105, which corresponds to 6.5 × 1018 (ca. 10-5 mol) of holes or molecules of 1 adsorbed in holes per gram of zeolite. The supramolecular composition of ca. 0.3-0.5% of 1 on LZ-105 characterizes a "break point" for the photochemistry and the EPR measurements, since it represents the value for saturation of the site I holes with 1. These conclusions are supported quantitatively by experimental isotherms of the adsorption of 1 on LZ-105. Photolysis of 1 intercalated in the site I holes causes fragmentation into two isomeric supramolecular diphenylmethyl (DPM) radicals, one (DMP)in which is adsorbed into the internal surface and becomes strongly persistent (half-life of many weeks) and the other (DMP)ex which diffuses on the external surface and rapidly dimerizes (less than a few minutes) to produce the radical-radical combination product tetraphenylethane (2). Photolysis of 1 adsorbed on the solid external surface produces two supramolecularly equivalent DPM radicals (DMP)ex that diffuse on the external surface and rapidly dimerize to produce 2, and do not produce persistent DPM radicals. * To whom correspondence should be addressed.
Regioselective Allylation of Ketenes Promoted by SmI2
Miyoshi, Norikazu,Takeuchi, Seiji,Ohgo, Yoshiaki
, p. 445 - 451 (2007/10/02)
Ketenes react with various allylic halides mediated by 2 equiv. samarium(II) diiodide (SmI2) to the ketenes to afford allylated ketones in good yields.In the reaction with γ-substituted allylic halides, the regioselectivity is influenced by the olefinic geometry of allylic halides.By using γ-substituted (E)-allylic halides, the allylation proceeds on the less hindered site (α-position) of allylic groups predominantly and the tendency was enhanced by the addition of HMPA.
Low-valent titanium induced reductive coupling reaction of carboxylic derivatives with aromatic ketones
Shi, Da-Qing,Chen, Jian-Xie,Chai, Wen-Ying,Chen, Wei-Xing,Kao, Tsi-Yu
, p. 2963 - 2964 (2007/10/02)
The intermolecular and intramolecular coupling reaction of carboxylic derivaties with aromatic ketones induced by titanium tetrachloride and zinc powder was studied.
Nucleophilic Addition of Lanthanoid Metal Umpoled Diaryl Ketones to Electrophiles
Hou, Zhaomin,Takamine, Kan,Aoki, Osamu,Shiraishi, Hiroyuki,Fujiwara, Yuzo,Taniguchi, Hiroshi
, p. 6077 - 6084 (2007/10/02)
Ytterbium metal promoted cross-coupling reactions of diaryl ketones with a variety of electrophiles are described.Diaryl ketones treated with 1-2 equiv of Yb metal react smoothly with other ketones, nitriles, epoxides, CO2, etc., to give the corresponding unsymmetrical pinacols, α-hydroxy ketones, 1,3-diols, α-hydroxy carboxylic acids, etc., in good yields respectively.These reactions occur via nucleophilic addition of the intermediates 4a-c to electrophiles.Reaction of benzophenone (1a) with Yb metal is discussed in detail and some information on the composition of the intermediates of the reaction of diaryl ketones with Yb metal are also given.
