956-89-8Relevant articles and documents
Decarbonylation of phenylacetic acids by high valent transition metal halides
Bartalucci, Niccolò,Marchetti, Fabio,Zacchini, Stefano,Pampaloni, Guido
, p. 5725 - 5734 (2019/05/10)
Triphenylacetic acid underwent unusual decarbonylation when allowed to react with a series of halides of group 4-6 metals in their highest oxidation state, in dichloromethane at ambient temperature. Thus, the reaction of CPh3COOH with MoCl5, in 1:1 molar ratio, afforded the trityl salt [CPh3][MoOCl4], 1, in 79% yield, while the 1:2 reaction of CPh3COOH with NbF5 afforded [CPh3][NbF6], 2, in 70% yield, NbOF3 being the metal co-product. CPh3COOH reacted with NbCl5, TiF4 and WOCl4 to give mixtures of compounds, however the cation [CPh3]+ was NMR identified in each case. [CPh3][NbCl6], 3, was isolated from NbCl5 and CPh3COCl, prior to being generated from CPh3COOH and PCl5. The reaction of CPh3COOH with TiCl4 was non-selective, and the salt [CPh3][Ti2Cl8(μ-κ2-O2CCPh3)], 4, was obtained in 18% yield. The decarbonylation reactions of CMePh2COCl and CMe2PhCOCl by means of NbCl5 led to the indanes 5a-b, which were isolated in 79-97% yields after hydrolysis of the mixtures and subsequent alumina filtration of the organic phases. The reactions of CH(Ph)2COOH with NbCl5 and WCl6 afforded NbCl4(OOCCHPh2), 6, and CHPh2COCl, respectively, as the prevalent species. CPh2(CH2CH2Br)COOH did not undergo CO release when allowed to interact with WCl6, instead selective intramolecular condensation to C(Ph)2C(O)OCH2CH2, 7, occurred. MeCCCOOH underwent hydrochlorination by WCl6 to give MeC(Cl)CHCOOH, 8, in 72% yield. All the products were fully characterized by elemental analysis, IR and multinuclear NMR spectroscopy. In addition, the solid state structures of 1, 2, 4, 7, and 8 were elucidated by X-ray diffraction.
Thermal rearrangement of phenyl-substituted ketene ethylene acetals
Oda, Mitsunori,Morimoto, Kazuo,Thanh, Nguyen Chung,Ohta, Reina,Kuroda, Shigeyasu
, p. 1673 - 1680 (2007/10/03)
Thermal rearrangement of mono-, di-, and triphenyl-substituted ketene ethylene acetals was studied. Pyrolysis of all of these acetals provided phenyl-substituted tetrahydro-2-furanones as a major product. The more phenyl groups substitute on the ketene acetal skeleton, the lower reaction temperature was required for the rearrangement. In the cases of the diphenylketene acetals at high temperatures, fragmentation products, such as fluorene and benzophenone, probably derived from dipheylcarbene via diphenylketene, were observed.
Regioselectivity in Nickel(II)-Mediated Oxidations of Diols
Doyle, Michael P.,Dow, Robert L.,Bagheri, Vahid,Patrie, William, J.
, p. 476 - 480 (2007/10/02)
Oxidations of 2- and 4-substituted 1,4-butanediols to their corresponding γ-butyrolactones by the combination of molecular bromine and nickel(II) alkanoate occur with a high degree of regioselectivity.The influence of the alkanoate ligand, of substituents at the 2-position of 1,4-butanediols, and of solvent on oxidation regiocontrol is examined, and comparison of regioselectivity in diol oxidations is made with representative conventional oxidative methods.Regiocontrol in nickel(II)-mediated reactions is proposed to be derived from steric constraints for oxidativehydrogen transfer to the alkanoate ligand of nickel(II) in the diol-associated complex.Alternate use of cobalt(II) alkanoates provides regiocontrol in diol oxidations that is comparable or superior to that obtained with nickel(II) alkanoates in bromine oxidations.
