Pyridinium Chloride: a New Reagent for N-Demethylation of N-Methylazinium Derivatives.
摘要:
A new N-demethylation reaction of N-methylazinium derivatives by using boiling pyridinium chloride is described. The reaction is quite clean, fast and yields are almost quantitatives. (C) 1997 Elsevier Science Ltd.
Reactivity of Phosphorus-Centered Radicals Generated during the Photoreaction of Diphenylphosphinous Acid with 10-Methylacridinium Salt
摘要:
Diphenylphosphinous acid (1) reacts with 10-methylacridinium iodide (2a) in aqueous acetonitrile during irradiation by visible light under an argon atmosphere at 20 degrees C to afford diphenylphosphinic acid (3) and 10-methylacridan (4). The effects of the solvent and atmosphere and the effect of added iodide ion (I-) or iodine (I-2) on the product distribution show that the mechanism involves initial single-electron transfer (SET) from 1 to 2a in the photoexcited state, by which cation radical 1(+.) and dihydroacridinyl radical 2(.) are generated. Cation radical 1(+.) undergoes electrophilic reaction with water in the solvent, and the resulting phosphoranyl radical decomposes through SET to iodine atom (I-.) rather than undergoing beta-scission, eventually giving 3. Protonation to 2(.) followed by reduction by I- affords 4. These reaction sequences make up the catalytic I-./I- couple. The results are interpreted on the basis of reported redox potentials.
Manganese(v)–oxo corroles in hydride-transfer reactions
作者:Yejee Han、Yong-Min Lee、Mariappan Mariappan、Shunichi Fukuzumi、Wonwoo Nam
DOI:10.1039/c0cc03373a
日期:——
proceeds via proton-coupled electron transfer, followed by rapid electron transfer. The redox potentials (E(red)) of manganese(V)-oxo corroles exhibit a good correlation with their reactivity in hydride-transferreactions.
<i>N</i>-Methylacridinium Salts: Carbon Lewis Acids in Frustrated Lewis Pairs for σ-Bond Activation and Catalytic Reductions
作者:Ewan R. Clark、Michael J. Ingleson
DOI:10.1002/anie.201406122
日期:2014.10.13
N‐methylacridinium salts are Lewis acids with high hydride ion affinity but low oxophilicity. The cation forms a Lewis adduct with 4‐(N,N‐dimethylamino)pyridine but a frustrated Lewis pair (FLP) with the weaker base 2,6‐lutidine which activates H2, even in the presence of H2O. Anion effects dominate reactivity, with both solubility and rate of H2 cleavage showing marked anion dependency. With the optimal
Frustrated Lewis Pair Mediated 1,2-Hydrocarbation of Alkynes
作者:Valerio Fasano、Liam D. Curless、James E. Radcliffe、Michael J. Ingleson
DOI:10.1002/anie.201705100
日期:2017.7.24
FrustratedLewispair (FLP) chemistry enables a rare example of alkyne 1,2-hydrocarbation with N-methylacridinium salts as the carbon Lewis acid. This 1,2-hydrocarbation process does not proceed through a concerted mechanism as in alkyne syn-hydroboration, or through an intramolecular 1,3-hydride migration as operates in the only other reported alkyne 1,2-hydrocarbation reaction. Instead, in this study
cofactors with iron–sulfur heterocubane core structures, [Fe4S4], are often found in nature as electrontransfer reagents in fundamental catalytic transformations. An artificial heterocubane with a [Fe4N4] core is reported that can reversibly store up to four electrons at very negative potentials. The neutral [Fe4N4] and the singly reduced low‐valent [Fe4N4]− heterocubanes were isolated and fully characterized
具有铁-硫杂铜核心结构[Fe 4 S 4 ]的酶和辅助因子通常在自然界中作为基本催化转化中的电子转移试剂被发现。据报道,具有[Fe 4 N 4 ]核的人工杂化物可以在非常负的电势下可逆地存储多达四个电子。中性[Fe 4 N 4 ]和单个还原的低价[Fe 4 N 4 ] -分离并充分鉴定了杂合体。低价物质带有一个不成对的电子,该电子主要位于电子基态的一个铁中心,但随着温度的升高而波动。[Fe 4 N 4 ] / [Fe 4 N 4 ] -氧化还原对存储或释放的电子可用于还原性或氧化性CC耦合,甚至可进行催化一锅法反应,这表明该化合物的选择性显着提高。 [Fe 4 N 4 ]杂合子的存在。