A new method for the synthesis of macrocyclic ketones

Summary We have described the synthesis of macrocyclic diacetylene ketones by oxidative condensation of aliphatic ,-diacetyiene ketones.     

A new method for the catalytic aldol reaction to ketones

A new method for the catalytic aldol reaction to ketones, using CuF.3PPh3.2EtOH complex as the catalyst and (EtO)3SiF as the additive, is described. The reaction can be applied to a wide range of ketones and trimethylsilyl enolates. On the basis of mechanistic studies, a working hypothesis for the catalytic cycle is proposed, in which the dynamic ligand exchange mediated by copper silicates produces the active copper enolate. Moreover, the present reaction can be extended to the catalytic enantioselective reaction using tol-BINAP as a chiral ligand.     

The reaction of α-methoxyvinyllithium with trialkylboranes

Several alkenyltrialkylborate salts derived from the reaction of α-methoxyvinyllithium (MVL) with trialkylboranes have been prepared. At ?80°C, the initial complex is stable as indicated by its iodination to give moderate yields of enol ethers. Warming the complex to room temperature leads via an alkyl group migration to a new alkenyldialkylmethoxyborate salt. Oxidation of this complex leads to methyl ketones. Alternatively, treatment of this salt with various electrophiles, such as acid, iodine, or alkylating agents prior to oxidation leads to methyldialkylcarbinols, 1,1-dialkylethylenes and hindered tertiary alcohols, respectively. The products can be rationalized by electrophilic attack at the β carbon of an alkenylborate salt. The remarkable nucleophilicity of these salts appears to be comparable to that of enamines.     

A simple and convenient method for synthesis of new aminonaphthoquinones derived from lawsone by catalytic multicomponent Mannich reaction

A clean, efficient and facile one-pot protocol was developed for the synthesis of a series of new aminonaphthoquinones derived from 2-hydroxy-1,4-naphthoquinone (lawsone) by three-component Mannich reaction using catalytic amount of p-TsOH in CH₃CN, at room temperature. At the present work, we improved the yield and significantly reduced the reaction time for several Mannich reactions with different amine and aromatic aldehydes using a non-expensive, mild catalyst and suitable solvent.     

Iodine-mediated new strategy for the synthesis of 2,5-disubstituted oxazoles from methyl ketones and TosMIC

A new strategy has been developed for the construction of oxazoles from methyl ketones and TosMIC via self-sorting oxidative domino reaction strategy. In contrast to its usual reactivity as C–N≡C synthon in the synthesis of oxazoles, TosMIC was utilized as ammonium surrogate in the present method. The protocol is attractive in terms of readily available starting materials, metal and base free conditions, operational simplicity, C–N and C–O bond formation. A variety of 2,5-disubstituted oxazoles were prepared in moderate-to-good yields.     

酰基过氧化物的化学IV.全氟酰基过氧化物与硝基烷烃阴离子间的单电子转移反应-一种合成醛,酮的新反应

标题反应于室温在F113(CC1F2CCl2F)溶液中瞬间完成。产物经分析确定,该反应由硝基烷烃阴离子(R[1]R[2]CNO2)向全氟酰基过氧化物(RfCO2)2的单电子转移的决速步骤,生成全氟羧酸盐,全氟酰氧基自由基之脱羧偶合产物RF-RF(1)及硝基烷烃自由基偶合产物DN(2);但主要的产物是自由基笼内结合所生成的中间体立即发生1,2-消除得到的醛或酮,本文提供了一个由硝基烷烃合成相应醛和酮的新反应。     

Imino-bridged heterocycles. IV . A facile synthesis of sulfenimines derived from diaryl ketones

Efficient, high-yield syntheses of N-diarylmethylene sulfenamides (sulfenimines) have been developed under mild laboratory conditions. Diaryl ketones have been shown to form ketimines readily by condensation with ammonia in the presence of titanium tetrachloride.     

A new method for the synthesis of CF3-containing aminovinyl ketones

A new method for the synthesis of aminovinyl trifluoromethyl ketones was developed. The method is based on the reactions of 4-sulfonyl-1,1,1-trifluorobut-3-ene-2,2-diols with various alkyl-, aryl-, dialkyl-, and alkylarylamines. The stereochemistry of the compounds obtained was studied.     

Phenyl selenium trichloride in synthesis. Reaction with ketones. A new variation of the selenoxide elimination reaction

Phenyl selenium trichloride was used for the introduction of a PhSeCl₂-group into the α-position of ketones. These products were converted to enones (hydrolysis/selenoxide elimination) or α-phenylselenoketones (thiourea-reduction).     

A new regiospecific synthesis of aryl ketones from palladocycles

Aromatic palladocycles undergo facile reaction with acid halides to reglospecifically provide aryl ketones In high yield.     

A novel pyrrole synthesis via reaction of ketones with N-aminoimides

A new, mild synthesis of pyrroles using N-aminoimides and a ketone is described. The reaction has been utilized in the synthesis of dimeric morphinans containing a connecting pyrrole ring. The reaction appears to proceed through a diacylhydrazone intermediate, and it is suggested that the driving force behind the reaction is the facility with which a protonated imide moiety operates as a leaving group.