22705-26-6Relevant academic research and scientific papers
Mechanism of the palladium-catalyzed arene C-H acetoxylation: A comparison of catalysts and ligand effects
Cook, Amanda K.,Sanford, Melanie S.
supporting information, p. 3109 - 3118 (2015/03/18)
This article describes detailed mechanistic studies focused on elucidating the impact of pyridine ligands on the Pd-catalyzed C-H acetoxylation of benzene. Three different catalysts, Pd(OAc)2, Pd(OAc)2/pyridine (1:1), and Pd(OAc)2/pyridine (1:2), are compared using a combination of mechanistic tools, including rate and order studies, Hammett analysis, detailed characterization of catalyst resting states, and isotope effects. The data from these experiments implicate C-H activation as the rate-limiting step in all cases. The major difference between the three catalysts is proposed to be the resting state of Pd. Under the reaction conditions, Pd(OAc)2 rests as an acetate bridged dimer, while the Pd(OAc)2/pyridine (1:2) catalyst rests as the monomer (pyridine)2Pd(OAc)2. In contrast, a variety of experiments suggest that the highly active catalyst generated from the 1:1 combination of Pd(OAc)2 and pyridine rests as the dimeric structure [(pyridine)Pd(OAc)2]2.
Silver-catalyzed functionalization of esters by carbene transfer: The role of ylide zwitterionic intermediates
Gava, Riccardo,Fuentes, M. Angeles,Besora, Maria,Belderrain, Tomas R.,Jacob, Kane,Maseras, Feliu,Etienne, Michel,Caballero, Ana,Perez, Pedro J.
, p. 2206 - 2210 (2014/08/18)
The reaction of esters with ethyl diazoacetate catalyzed by the complex [F27-Tp4Bo,3CF2CF3Ag(acetone)] generates α-(acyloxy)acetates in moderate to high yields. This is a novel transformation in the context of carbene-transfer reactions from diazo compounds that, according to experimental and theoretical data, is suggested to occur through zwitterionic intermediates.
Remarkably high reactivity of Pd(OAc)2/pyridine catalysts: Nondirected C-H oxygenation of arenes
Emmert, Marion H.,Cook, Amanda K.,Xie, Yushu J.,Sanford, Melanie S.
supporting information; experimental part, p. 9409 - 9412 (2011/11/07)
Less is more: The rational optimization and general applicability of the catalytic system Pd(OAc)2/pyridine is described (see scheme). The catalyst shows excellent reactivity in the C-H oxygenation of simple aromatic substrates. The Pd/pyridine ratio is critical as the use of one equivalent of pyridine per Pd center leads to dramatic enhancements in both reactivity and site selectivity in comparison to Pd(OAc)2 alone.
Semi-empirical and vibrational studies of flavone and some deuterated analogues
Vrielynck, L.,Cornard, J. P.,Merlin, J. C.,Lautie, M. F.
, p. 2177 - 2188 (2007/10/02)
The infrared solid state, Raman solid state and tetrachloride solution spectra of flavone have been obtained.Assignments of most of the vibrational data have been performed by comparison between the spectra of flavone and three isotopic species, deuterated on the A, B and C rings, respectively.The vibrational frequencies for all the investigated compounds have been calculated from the conformational analysis of flavone using the semi-empirical AM1 method and compared with experimental values.The correlation is more or less satisfactory; however, for some vibrational modes, the calculated isotopic shifts agree better with experiment than do the frequencies themselves.Specific vibrational modes which retain a benzene ring mono-substituted and ortho-distributed character have been recognized in the spectra, according to literature data, isotopic frequency shifts and graphic representation of the atomic displacements.
