- The Barbier-Grignard-Type Arylation of Ketones and Unexpected Cross-Coupling of Phenolic Ketones using Unactivated Aryl Bromides
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A novel, highly versatile and efficient method has been developed for the Barbier-Grignard-type arylation of ketones and an unexpected cross-coupling of phenolic ketones was observed using unactivated bromides and magnesium in tetrahydrofuran/toluene at 96°C promoted by multicatalysts of cupric bromide (15 mol%), bismuth chloride (5 mol%) and silver bromide (10 mol%). The substituent and electronic effects on the reaction have been discussed. High yields of arylation and cross-coupling have been attained under mild conditions. A novel reasonable mechanism involving a quinone intermediate is proposed. The high chemical selectivity in the cross-coupling to the hydroxy group of phenolic ketones should help ketones find new applications.
- Wen, Yunming,Chen, Guifang,Huang, Shiqiang,Tang, Yu,Yang, Jun,Zhang, Yuanming
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p. 947 - 957
(2016/04/05)
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- A convenient synthesis of 2-naphthylcyclopentanones and 2-naphthylcyclohexanones from 1-naphthylcycloalkenes
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The oxidation of naphthylcycloalkenes with hydrogen peroxide or MCPBA followed by acid catalyzed rearrangement of diol (epoxide), afforded a series of naphthylcycloalkanones in a very simple manner. The conditions allow preparation of naphthylcycloalkanones on a multigram scale. Georg Thieme Verlag Stuttgart.
- Gora, Maciej,Luczynski, Michal K.,Sepiol, Janusz J.
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p. 1625 - 1630
(2007/10/03)
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- Oxidative fragmentation of 1-aryl-1-cycloalkenes using cerium(IV) ammonium nitrate (CAN): Some novel observations
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1-Phenyl-1-cycloalkenes undergo oxidative fragmentation in presence of CAN in methanol, affording 1,n-dicarbonyl compounds as the major products along with 1,2-dimethoxycycloalkanes. The reaction under deoxygenated conditions afforded the latter in good yields. In the presence of azide ion, fragmentation leading to the corresponding cyanoketones was observed whereas with sulfinate only the 1-methoxy-2-sulfonyl cycloalkanes were formed.
- Nair, Vijay,Panicker, Sreeletha B,Thomas, Siji,Santhi,Mathai, Sindhu
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p. 3229 - 3234
(2007/10/03)
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- Enantioselective protonation of samarium enolates derived from α- heterosubstituted ketones and lactone by SmI2-mediated reduction
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SmI2-mediated reductive cleavage of α-heterosubstituents of α-alkyl or α-aryl ketones and lactone gave the corresponding 'thermodynamic samarium enolates'. Enantioselective protonation of the samarium enolates with C2- symmetric chiral diols afforded the corresponding ketones and lactone in moderate to high enantioselectivities.
- Nakamura, Yutaka,Takeuchi, Seiji,Ohgo, Yoshiaki,Yamaoka, Makoto,Yoshida, Akihiro,Mikami, Koichi
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p. 4595 - 4620
(2007/10/03)
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- THE SYNTHESIS OF SOME 1-NAPHTHYLCYCLOALKANOLS AND 1-NAPHTHYLCYCLOALKENES
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1-Naphthylcycloalkanols having 3, 4, 5, 6, 7, 12 and 15 ring carbons were synthesized from corresponding cyclic ketones and 1-naphthylbromide using Grignard reaction. The dehydration products of these naphthylcycloalkanols were obtained. All the products were identified by means of IR- and 1H-NMR spectra.
- Guenaydin, Keriman
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p. 925 - 930
(2007/10/03)
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- Triplet State of α-Naphthylethylene Derivatives. Structural Effects on the Equilibrium between Planar and Perpendicular Triplet Conformations
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The properties of the triplet state of a series of 1-(α-naphthyl)ethylene derivatives have been studied by laser flash photolysis.The geometry of the triplet state has been determined from the T-T absorption spectra, the lifetime values, and the quenching rate constants by oxygen, stilbene, and ferrocene.The triplet state can be either planar (nontwisted double bond), when the ethylenic moiety is inserted into a small ring, or perpendicular (double bond twisted by 90 deg), when the planar geometry is disfavored by a strong steric hinderance.However, in most cases, there is a fast equilibrium between the planar and perpendicular triplets.These two geometries are very close in energy and therefore the equilibrium can be greatly modified by small changes in the molecular structure such as an alkyl substitution.By comparison of the triplet state of 1-(α-naphthyl)-1-phenylethylene with that of other 1-aryl-1-phenylethylenes, an experimental correlation is found between the percentage of planar triplet and the triplet energy of the aryl group.
- Lazare, Sylvain,Bonneau, Roland,Lapouyade, Rene
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