1031683-94-9Relevant academic research and scientific papers
SYNTHESIS OF DEUTERATED ALDEHYDES
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Paragraph 0008; 00116, (2021/03/13)
Described are methods for preparing a deuterated aldehyde using N-heterocyclic carbene catalysts in a solvent comprising D2O. The methods may be used to convert a wide variety of aldehydes (e.g., aryl, alkyl, or alkenyl aldehydes) to C-1 deuterated aldehydes under mild reaction conditions without functionality manipulation.
Differences in the Mechanisms of MnO2Oxidation between Lignin Model Compounds with the p-Hydroxyphenyl, Guaiacyl, and Syringyl Nuclei
Sun, Shirong,Akiyama, Takuya,Yokoyama, Tomoya,Matsumoto, Yuji
, p. 6819 - 6825 (2020/07/02)
The purpose of this study was to examine how the rate and mechanism of MnO2 oxidation differ between the p-hydroxyphenyl (H), guaiacyl (G), and syringyl (S) types of simple nonphenolic lignin model compounds as well as the p-ethylphenyl (E) type compounds. The oxidation was conducted using an excess amount of MnO2 in a sulfate buffer solution at a pH value of 1.5 at room temperature. MnO2 oxidized at least the G and S nuclei, although it commonly oxidizes alcohols present at the benzyl position. The oxidation rates of the benzyl alcohol derivatives were in the order of G- > S- ? H- > E-type, which suggests that the rates are determined by the electronic effects of their methoxy and ethyl functional groups on not only their benzyl positions but also their aromatic π-electron systems. The kinetic isotope effect was observed in the MnO2 oxidations of the same derivatives deuterated at their benzyl hydroxymethyl groups. The observed magnitudes were in the order of E- ? H- > G- ? S-type, suggesting that the contribution of oxidation of their aromatic nuclei, which is another reaction mode of the oxidation of their benzyl positions, increases in the reverse order.
Experimental and theoretical mechanistic investigation of the iridium-catalyzed dehydrogenative decarbonylation of primary alcohols
Olsen, Esben P. K.,Singh, Thishana,Harris, Pernille,Andersson, Pher G.,Madsen, Robert
supporting information, p. 834 - 842 (2015/01/30)
The mechanism for the iridium-BINAP catalyzed dehydrogenative decarbonylation of primary alcohols with the liberation of molecular hydrogen and carbon monoxide was studied experimentally and computationally. The reaction takes place by tandem catalysis through two catalytic cycles involving dehydrogenation of the alcohol and decarbonylation of the resulting aldehyde. The square planar complex IrCl(CO)(rac-BINAP) was isolated from the reaction between [Ir(cod)Cl]2, rac-BINAP, and benzyl alcohol. The complex was catalytically active and applied in the study of the individual steps in the catalytic cycles. One carbon monoxide ligand was shown to remain coordinated to iridium throughout the reaction, and release of carbon monoxide was suggested to occur from a dicarbonyl complex. IrH2Cl(CO)(rac-BINAP) was also synthesized and detected in the dehydrogenation of benzyl alcohol. In the same experiment, IrHCl2(CO)(rac-BINAP) was detected from the release of HCl in the dehydrogenation and subsequent reaction with IrCl(CO)(rac-BINAP). This indicated a substitution of chloride with the alcohol to form a square planar iridium alkoxo complex that could undergo a β-hydride elimination. A KIE of 1.0 was determined for the decarbonylation and 1.42 for the overall reaction. Electron rich benzyl alcohols were converted faster than electron poor alcohols, but no electronic effect was found when comparing aldehydes of different electronic character. The lack of electronic and kinetic isotope effects implies a rate-determining phosphine dissociation for the decarbonylation of aldehydes.
