Determination of aromaticity indices of thiophene and furan by nuclear magnetic resonance spectroscopic analysis of their phenyl esters
作者:Chang Kiu Lee、Ji Sook Yu、Hye-Jin Lee
DOI:10.1002/jhet.5570390615
日期:2002.11
series of m- and p-substituted phenyl benzoates, 2-thienoates, and 2-furoates were prepared and their 1H and 13C nmr spectroscopic characteristics were examined. In general, good correlations were observed between the chemical shift values of protons and carbons of the acyl aromatic rings and the Hammett σ. Plots of the chemical shift values of the carbonyl carbons of the benzoates against those of
presence of a copper catalyst using PhMe2Si-B(pin) and esters as the silyl and acyl sources, respectively. β-Silyl-β,γ-unsaturated ketones are obtained regioselectively in good to high yields. The sila-imination of allenes is also achieved using nitriles as electrophiles. Exposure of the reaction mixture to air results in the production of cyclic silyl peroxides.
tertiary benzylic coppercomplexes from Cu–B(pin) (pin = pinacolato) additions to 1,1-disubstituted alkenes followed by in situ reactions with ketones and carboxylic acid phenol esters to construct multifunctional alkylboron compounds that contain quaternary stereogenic centers is presented. The method is distinguished by the unprecedented reaction mode of tertiary benzylic Cu complexes, allowing reaction
(a(1–4)), anilines and amine derivatives (a(5–9)), picolinic-2-carboxamide derivatives of benzophenones and acetophenone (a(10–12)) and furan-2-carboxylate esters of benzophenones and acetophenones, substituted phenols and alcohols (b(1–7)). All the necessary steps were taken to synthesize, purify, and characterize these compounds. They were synthesized by reacting acyl chlorides of the heterocycles with