from NaIO 4 and either I 2 or KI in concentrated H 2 SO 4 (minimum 95% by weight). In general a small excess of the dark brown iodinating solution was used (1.1/1.5 equivalents, for nitrobenzene two equivalents was required). The iodinations were conducted at 25-30 °C with a reaction time of 1-2 hours using either a 'direct' or an 'inverse' method of aromatic iodination to give mono- or diiodinated pure
用强亲电 I + 试剂对失活的芳烃进行单碘化或二碘化,这些试剂由 NaIO 4 和 I 2 或 KI 在浓 H 2 SO 4 中制备(至少 95% 重量)。通常使用稍微过量的深棕色碘化溶液(1.1/1.5 当量,对于硝基苯需要两个当量)。碘化在 25-30 °C 下进行,反应时间为 1-2 小时,使用芳香族碘化的“直接”或“反向”方法以 31-91% 的优化产率得到单碘化或二碘化纯产物。
Tetraalkylammonium Dichloroiodates as Iodinating Agents: Absence of Activity in Solid Phases and Superelectrophilic Activity in Sulfuric Acid
In contrast to published results, tetraalkylammonium dichloroiodates (Alk4N+ICl2 -) cannot be iodinating reagents for arenes in solvent-free conditions. Nevertheless, tetraalkylammonium dichloroiodates in sulfuric acid solutions or in the presence of Ag2SO4 in H2SO4 possess superelectrophilic properties and act as very convenient and efficient iodinating agents for deactivated arenes.
Superactive Iodination Reagent on a Base of Iodine Chloride and Silver Sulfate
作者:Vitold K. Chaikovski、Tatjana S. Kharlova、Victor D. Filimonov、Tamara A. Saryucheva
DOI:10.1055/s-1999-3475
日期:1999.5
After reaction of ICl and Ag2SO4 in sulfuric acid and separation of resulting AgCl a stable solution is formed, containing very active forms of electrophilic iodine. This solution has a powerful iodination ability with respect to aromatic compounds. Deactivated arenes are iodinated easily and in mild conditions by action of this new reagent in generally good yields of the iodoarenes.
The Direct Iodination of Arenes with Chromium(VI) Oxide as the Oxidant
作者:Piotr Lulinski、Lech Skulski
DOI:10.1246/bcsj.70.1665
日期:1997.7
An easy and cheap laboratory method is presented for the direct mono- and diiodination of a number of activated and deactivated arenes. The main iodination reactions occurred at the temperatures not exceeding 65 °C for 0.5—12 h in the anhydrous, strongly acidic liquid system, I2/AcOH/Ac2O/H2SO4, in the presence of prior dissolved CrO3 used as the oxidant. The yields of the pure iodinated products varied from 31% (for 3,5-diiodobenzoic acid) up to 90% (for 4-iodoanisole). So far, benzonitrile and some oxidizable aromatics, e.g. naphthalene, fluorene, xanthene, and thiophene, have been found to be unsuitable for the effective iodination. Nevertheless, this novel, simple method of direct iodination is worthy to be extended to other appropriate aromatics.
reductive coupling reaction was established for the synthesis of diaryl 1,2-dicarbonyl compounds from arylmethyl ketones in good yields. The mechanisticstudy showed the reaction undergoes C(CO)–C(sp3) bond cleavage, with the reductive coupling reaction occurring through an electron transfer process. Notably, the reaction not only is simple to operate but also has mild reaction conditions and a wide