10.1021/jo00334a035
The research focuses on the photochemical behavior of α,β-epoxy ketones, specifically those bearing a benzoyl group and preferentially excited in the triplet state. The purpose of the study was to determine the effect of the localization of excitation energy in the starting molecule on the course of rearrangement and fragmentation reactions. The researchers found that depending on the localization of energy, photolysis of these compounds leads to β-diketones, α-diketones, or fragmentation products. They observed that the phosphorescence spectra and the behavior in direct or sensitized experiments suggest that only triplet excited states are involved in the photo-rearrangement of α,β-epoxy ketones. The chemicals used in this process included α,β-epoxy ketones 1-5, which absorb UV light similarly to aromatic ketones, and various solvents such as benzene and acetonitrile that showed a strong effect on the composition of the reaction mixture. The study concluded that the formation of different types of products, such as β-diketones, α-diketones, and aldehydes, can be rationalized by different bond cleavages following the energy transfer and excitation state of the molecules.
10.1007/BF00953106
The research aimed to investigate the effect of Lewis acids on the decarboxylation of α-nitroalkanecarboxylic acid chlorides. The study found that aluminum chloride (AlCl?) and aluminum fluoride (AlF?) readily induce decarboxylation of these acid chlorides, with AlCl? being more effective than AlF?. The reaction, when conducted in the absence of a solvent, results in a complex mixture from which pure products cannot be isolated. However, a nitroso compound can be obtained in approximately 50% yield when the reaction is carried out in hexane. The researchers also noted that the acid chlorides do not decarboxylate in the presence of AlCl? in either absolute benzene or toluene, instead forming aromatic acids upon hydrolysis.
10.1021/jo00191a003
The study explores a direct method for the periodination of aromatic compounds using periodic acid (HIO?) and iodine in concentrated sulfuric acid. This method allows for the exhaustive iodination of unactivated aromatic substrates such as benzene, nitrobenzene, benzoic acid, chlorobenzene, phthalic anhydride, and toluene, converting them into their respective periodo derivatives. The study also reports the conversion of benzonitrile to pentaiodobenzamide. The direct periodination method is compared favorably to the existing mercuration/iododemercuration sequence in terms of reaction time and purity of products. The study highlights the versatility of the method, demonstrating that partially iodinated products can be obtained under less vigorous conditions. Additionally, the study discusses the limitations of the method, noting that certain activated aromatics and easily oxidized substrates do not fare well under these conditions. The research provides detailed experimental procedures and characterizations of the synthesized compounds, contributing to the field of organic chemistry by offering a more efficient route for the preparation of polyiodinated and periodinated aromatic compounds.
10.1021/jo00146a025
The research explores the use of charge-directed conjugate addition reactions to synthesize substituted methyl ketones. The study focuses on the reactions of tert-butyl esters of α,β-unsaturated acylphosphoranes, which are manipulated through various chemical transformations to produce the desired ketones. The researchers also utilized solvents like benzene, chloroform, and tetrahydrofuran (THF) in their experiments. The methodology involves generating reactive ylide anions by adding nucleophiles to the unsaturated acylphosphoranes, followed by alkylation and subsequent transformations under acidic conditions to yield substituted (acylmethylene)phosphoranes, which are then hydrolyzed to obtain the methyl ketones. The study demonstrates the versatility of these unsaturated acylphosphoranes as equivalents to methyl vinyl ketone in conjugate addition-alkylation reactions, providing a valuable synthetic route for highly functionalized ketones.
10.1016/S0020-1693(00)84378-9
The study investigates the kinetics of substitution reactions of the metal carbonyl cluster Ru3(CO)10(dppm) with various weak nucleophiles, such as PPh3, PCy3, AsPh3, PPh2Et, P(OMe)3, and P(OEt)3, to form Ru3(CO)9(dppm)(L) in benzene. The reactions were conducted over a temperature range of 30-60 °C, and the kinetics were monitored by observing changes in UV-Vis and IR spectra. The study found that at lower temperatures, the reaction rate constants were independent of the nature or concentration of the nucleophile and were consistent with a simple CO dissociative mechanism. However, at higher temperatures, an additional reaction path became significant for reactions with PPh3 and dppm. The study also compared the activation parameters for these reactions and discussed possible mechanisms, including isomerization of the cluster and CO dissociation from a substituted metal atom. The results suggest that the dppm substituent is more labilizing than two PPh3 substituents, likely due to greater strain in the cluster caused by the bridging dppm ligand.
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F:Flammable;
