18321-24-9Relevant academic research and scientific papers
α-alkylation of ketones by addition of zinc enamides to unactivated olefins
Nakamura, Masaharu,Hatakeyama, Takuji,Nakamura, Eiichi
, p. 11820 - 11825 (2007/10/03)
A zinc enamide generated from the corresponding N-aryl imine undergoes addition to an unactivated olefin, such as ethylene, 1-octene, and isobutylene, to generate an α-alkylated γ-zincioimine intermediate in good to excellent yield. Terminal and gem-disubstituted olefins react with >99% regioselectivity, allowing the C-C bond formation to take place at the more hindered carbon of the double bond. The organozinc intermediate undergoes further C-C bond formation with a carbon electrophile to give, upon hydrolysis of the imine, an α-alkylated ketone bearing a variety of functionalized primary, secondary, and tertiary alkyl groups.
Synthetic utility of stannyl enolates as radical alkylating agents
Miura, Katsukiyo,Fujisawa, Naoki,Saito, Hiroshi,Wang, Di,Hosomi, Akira
, p. 2591 - 2594 (2007/10/03)
(Equation presented) The radical-initiated β-ketoalkylation of haloalkanes with tributylstannyl enolates is described. Stannyl enolates derived from aromatic ketones are reactive toward the homolytic β-ketoalkylation of simple haloalkanes as well as those activated by an electron-withdrawing group. The reactivity of stannyl enolates as radical alkylating agents can be utilized for an efficient three-component coupling reaction among stannyl enolates, haloalkanes, and electron-deficient alkenes.
Carba-methylephedrine and carba-pseudo-methylephedrine as tools for probing the role of the nitrogen atom of chiral amino alcohols in asymmetric synthesis
Cahard, Dominique,Ferron, Laurent,Plaquevent, Jean-Christophe
, p. 960 - 962 (2007/10/03)
As part of our on-going program on the use of chiral alkoxides as chiral bases in asymmetric synthesis, we report that carba-ephedrine analogues of N- methylephedrines, with a simple change of bridging nitrogen for CH, served to probe the role of the nitrogen atom in the discrimination of enantiotopic protons by means of the derived alkoxides. We suggest reasons why in the pseudo ephedrine series the asymmetric induction is retained while in the ephedrine series the enantioselectivity is strongly affected.
A Novel Synthesis of Highly Branched-Alkyl Aryl Ketones Using the Conjugate Addition of the Gilman Lithio Cuprate to β-Methylthio-α,β-unsaturated Ketones: Abnormal Reactivity of the Intermediary Enolates toward Molecular Oxygen
Arai, Takayuki,Akazome, Motohiro,Ogura, Katsuyuki
, p. 107 - 108 (2007/10/03)
In order to synthesize highly branched-alkyl aryl ketones, 1-(methylthio)-1-alken-2-yl phenyl ketones were subjected to the reaction with lithium dialkylcuprate. The high reactivity of an intermediary enolate toward molecular oxygen was found to give α-hy
Selective homologation of ketones and aldehydes with diazoalkanes promoted by organoaluminum reagents
Maruoka,Concepcion,Yamamoto
, p. 1283 - 1290 (2007/10/02)
Organoaluminum-promoted single homologation or ring expansion of ketones and aldehydes with diazoalkanes has been described, and among various organoaluminium reagents, exceptionally bulky methylaluminum bis(2,6-di-tert-butyl-4-methylphenoxide) (MAD) is found to be highly effective for the selective homologation of various ketones and aldehydes.
Organoaluminum-Promoted Homologation of Ketones with Diazoalkanes
Maruoka, Keiji,Concepcion, Arnel B.,Yamamoto, Hisashi
, p. 4725 - 4726 (2007/10/02)
Organoaluminum-promoted single homologation of aliphatic and aromatic ketones with diazoalkanes has been described, and among various organoaluminum reagents, especially bulky methylaluminum bis(2,6-di-tert-butyl-4-methylphenoxide) (MAD) is found to be highly effective for the selective homologation of various ketones.
The Allopolarization Principle and its Applications, IV. Substituent Effects in the Methylation of Enolate Anions
Gompper, Rudolf,Vogt, Hans-Hubert
, p. 2866 - 2883 (2007/10/02)
The ratio of O- and C-methylated products in the reaction of the sodium salts of acetophenones 1, propiophenones 3, phenylacetones 5, β-dicarbonyl compounds 12, α-cyanocarbonyl compounds 13, acetaldehyde, propionaldehyde, and diethylketone with dimethyl sulfate, methyl iodide, and trimethyl phosphate in HMPTA has been determined with regard to the effect of substituents.In some cases the influence of solvents, concentration and temperature has also been studied.
