25143-76-4Relevant academic research and scientific papers
Electroorganic Chemistry. 140. Electroreductively Intra- and Intermolecular Couplings of Ketones with Nitriles
Shono, Tatsuya,Kise, Naoki,Fujimoto, Taku,Tominaga, Naoto,Morita, Hiroshi
, p. 7175 - 7187 (2007/10/02)
Electroreduction of γ- and δ-cyano ketones in i-PrOH with Sn cathode gave α-hydroxy ketones and their dehydroxylated ketones as the intramolecularly coupled products.Guaiazulene, (-)-valeranone, polyquinanes, dihydrojasmone, methyl dihydrojasmonate, and rosaprostol have been synthesized by utilizing this electroreductive intramolecular coupling of γ- and δ-cyano ketones in one of the key steps.Similarly, electroreduction of a mixture of ketone and nitrile gave the corresponding intermolecularly coupled product.The product obtained by the electroreductive intermolecular coupling of (+)-dihydrocarvone with acetonitrile has been found to be the precursor of an effective chiral ligand for the enantioselective addition of diethylzinc to aldehydes.
Electroreductive intermolecular coupling of ketones with O-methyl oximes. A convenient route to synthesis of 2-amino alcohols
Shono, Tatsuya,Kise, Naoki,Fujimoto, Taku
, p. 525 - 528 (2007/10/02)
The electroreduction of ketones together with O-methyl oximes gave intermolecularly coupled products, 2-methoxyamino alcohols, which were easily reduced to 2-amino alcohols.
Amphiphilic Reactions by Means of Exceptionally Bulky Organoaluminum Reagents. Rational Approach for Obtaining Unusual Equatorial, Anti-Cram, and 1,4 Selectivity in Carbonyl Alkylation
Maruoka, Keiji,Itoh, Takayuki,Sakurai, Minoru,Nonoshita, Katsumasa,Yamamoto, Hisashi
, p. 3588 - 3597 (2007/10/02)
Exceptionally bulky, oxygenophilic organoaluminum reagents, methylaluminum bis(2,6-di-tert-4-alkylphenoxide) (MAD and MAT), have been successfully utilized for stereoselective activation of carbonyl moiety.Combination of MAD or MAT with carbon nucleophiles such as organolithiums or Grignard reagents generates a new amphiphilic reaction system in which the alkylation may be interpreted as the nucleophilic addition of a reactive organometallic compound to an electrophilically activated carbonyl substrate in order to account for the regio- and stereochemical consequences.In contrast to the ordinary alkylations, the amphilic alkylation disclosed herein would be categorized into the new, yet unexplored class of alkylation that exhibits high chemoselectivity to carbonyl compounds, and more significantly it allows excellent equatorial and anti-Cram selectivity in carbonyl alkylations, hitherto difficult by the existing methodologies.Further, unusual conjugate addition of organolithium reagents to α,β-unsaturated carbonyl compounds has been accomplished by using the amphiphilic reaction system.
STEREOCHEMICAL OUTCOME OF THE REACTION OF SOME α-SELENOALKYLLITHIUMS WITH 4-t-BUTYL CYCLOHEXANONE
Labar, D.,Krief, A.,Norberg, B.,Evrard, G.,Durant, F.
, p. 1083 - 1100 (2007/10/02)
α-selenoalkyllithiums were found to have a high propensity to add to 4-t-butyl cyclohexanone in an equatorial mode.Stereochemical assignments are discussed.
Synthesis of 2,2,-Disubstituted Oxetanes from Ketones with S-Methyl-S-(sodiomethyl)-N-(4-tolylsulfonyl)sulfoximine
Welch, Steven C.,Rao, A. S. C. Prakasa,Lyon, John T.,Assercq, Jean-Marie
, p. 252 - 257 (2007/10/02)
A covenient and facile one-step synthesis of 2,2-disubstituted oxetanes from ketones utilizing S-methyl-S-(sodiomethyl)-N-(4-tolylsulfonyl)sulfoxymine in dimethyl sulfoxide is presented.The stereochemistry and chemical reactivity of some 2,2-disubstituted
ORGANOMETALLIC REACTION MECHANISMS. XVIII. CONCERNING THE NATURE OF THE TRANSITION STATE IN THE REACTION OF TRIALKYLALUMINUM COMPOUNDS WITH KETONES
Ashby, E. C.,Smith, R. Scott
, p. 71 - 85 (2007/10/02)
Et2AlCH2AlEt2 (1) has been used as a mechanistic probe to determine the nature of the transition state in the reaction of two equivalents of a trialkylaluminum compound with a ketone in hydrocarbon solvent. 1 was prepared in benzene and the solution composition determined.Low temperature 1H NMR data of 1 as the mono(diethyl etherate) indicate that the ether oxygen is simultaneously coordinated to both aluminum atoms.The reactions of 1 with 4-t-butylcyclohexanone in hydrocarbon solvent were compared to the reactions of triethylaluminium with the same ketone.The results support the importance of a bridging alkyl group described by the formation of a six-centered transition state when two equivalents of a trialkylaluminum compound are allowed to react with a ketone in hydrocarbon solvent.The results also argue against a transition state described by two moles of trialkylaluminum compound complexed to the carbonyl oxygen atom.
THE ATE COMPLEXES OF ALUMINIUM. REACTIVITY AND STEREOSELECTIVITY WITH RESPECT TO EPOXIDES AND CARBONYL COMPOUNDS. CATALYTIC ACTIVATION BY SALTS OF TRANSITION METALS
Boireau, G.,Abenhaim, D.,Henry-Basch, E.
, p. 3061 - 3070 (2007/10/02)
When used in non-coordinating solvents (hydrocarbons) NaAlEt4 and LiAlnBu4 are good alkylation agents for epoxides.The presence of catalytic quantities of transition-metal salts, particularly NiCl2 or NiBr2, greatly accelerate the reactions, making them possible within a reasonable time in the case of disubstituted epoxides such as cyclohexene oxide, 2-3 epoxybutane, 1 phenyl-2,3-epoxybutane.In the case of aliphatic epoxides, dialkylmagnesium, NaAlEt4 and LiAlnBu4 lead mainly to alkylation of the least substituted carbon of the epoxide ring; while in the case of epoxides with C-O bond in the benzyl position, it is this carbon that is alkylated.The reaction always proceeds by total inversion of the configuration of the carbon in the epoxide ring, namely the site of the alkylation. NaAlEt4 is also good agent for alkylating carbonyl compounds when used in solvents of low basicity such as diethylether, or in totally non-coordinating solvents such as the hydrocarbons.The yields of the alcohol are greatly improved by using catalytic quantities of NiCl2.The behaviour of NaAlEt4 with 2-phenylpropanol is quite remarkable: in diethylether NaAl-Et4 gives predominantly the pair of enantiomers predicted by Cram's rule and with greater stereoselectivity than if EtMgBr was used, while in pentane the reaction is no longer stereoselective.Finally, with a cyclic ketone, 4-t-butylcyclohexanone, NaAlEt4 in diethylether and in hexane in the presence of NiCl2 gives predominantly the equatorial alcohol resulting from an axial attack, which is generally not favoured at all.
