α-Vinylation of 1,3-Dicarbonyl Compounds with Alkenyl(aryl)iodonium Tetrafluoroborates: Effects of Substituents on the Aromatic Ring and of Radical Inhibitors
1,3-dicarbonyl compounds with 4-tert-butyl-1-cyclohexenyl(aryl)iodonium 2 and 1-cyclopentenyl(aryl)iodonium tetrafluoroborates 3 are reported. Frequently, alpha-phenylations compete with the vinylations in the reaction of 1,3-dicarbonyl compounds with alkenyl(phenyl)iodoniumsalts 2a and 3a. Use of alkenyl(p-methoxyphenyl)iodoniumsalts 2b and 3b, however, leads to selective alpha-vinylation at the
mainly from the halo-λ3-iodane intermediate; the substitution occurs as a bimolecular reaction with the external halideion while the elimination is a unimolecular (intramolecular) reaction. The intermediacy of the hypervalent λ3-iodane as well as of the iodate are also confirmed by UV spectroscopy. The secondary kinetic isotope effects, leaving group substituenteffects, and pressure effects on the
Improving alkynyl(aryl)iodonium salts: 2-anisyl as a superior aryl group
作者:David J. Hamnett、Wesley J. Moran
DOI:10.1039/c4ob00556b
日期:——
majority of alkynyl(aryl)iodoniumsalts reported in the literature are derived from iodobenzene. This article describes the effects of varying this iodoarene building block on the synthesis, reactivity and stability of these salts. Two procedures to synthesize a variety of known and novel alkynyl(aryl)iodoniumtosylates directly from the iodoarene are reported. In the reactions of these salts, those derived
Structure of and electronic interactions in aromatic polyvalent iodine compounds: A
<sup>13</sup>
C NMR study
作者:Alan R. Katritzky、John K. Gallos、H. Dupont Durst
DOI:10.1002/mrc.1260270902
日期:1989.9
Available data on the structures, electronic substituent effects and 13C NMR spectra of aromatic polyvalent iodine compounds, particularly iodoso and iodoxy derivatives, are summarized and discussed. A series of aromatic tri‐ and penta‐valent iodine compounds were synthesized, their 13C NMR spectra were measured and the substituent chemical shifts (SCS) for several polyvalent iodine functional groups
总结和讨论了有关芳香族多价碘化合物,特别是碘代和碘氧基衍生物的结构、电子取代基效应和 13 C NMR 光谱的可用数据。合成了一系列芳香族三价和五价碘化合物,测量了它们的 13C NMR 光谱并计算了几个多价碘官能团的取代基化学位移 (SCS)。随着碘氧化态的增加(I→II→V),芳基碘化物中碘对ipso-碳原子的强屏蔽(30 ppm)显着降低,这种降低显然是一般用于稳定的高价碘化合物。讨论了可能的解释,并提出了化学位移、结构和/或电子效应之间的相关性。