在这里,我们将苯并[ b ]吩噻嗪的阴离子描述为可见光激发下的超级还原剂物种。与 N-取代的吩噻嗪或苯并吩噻嗪相反,该分子具有极高的还原能力,可在 -3.51 V vs SCE 的电位下促进基于单电子转移的还原裂解。作为证据,大量的芳基氯底物已被还原裂解以制造异吲哚酮和羟吲哚类分子。此外,芳基-氯键已均裂,生成芳基自由基,可用于 C-C 交叉偶联或 C-P 键形成反应。为了证明其极端的还原能力,一些芳基氟化物键被裂解以产生芳基自由基。包括稳态和时间分辨光谱技术在内的详细光物理研究解释了分子在光激发下的行为,以及与其反应模式相关的行为。理论计算表明,苯并吩噻嗪阴离子在基态时会稍微起皱,因为该分子本质上是反芳香族的。相反,激发态几何形状是平面的,这也接近一次电子转移后的中间体的几何形状。阴离子物质的反芳香性的减弱是其高度还原行为的部分原因。
Nickel or Phenanthroline Mediated Intramolecular Arylation of sp<sup>3</sup> C–H Bonds Using Aryl Halides
作者:William C. Wertjes、Lydia C. Wolfe、Peter J. Waller、Dipannita Kalyani
DOI:10.1021/ol402869h
日期:2013.12.6
the intramolecular arylation of sp3 C–Hbonds adjacent to nitrogen using aryl halides is described. Arylation was accomplished using either Ni(COD)2 or 1,10-phenanthroline in substoichiometric amounts, and the reaction conditions were applied to a variety of electronically differentiated benzamide substrates. Preliminary studies suggest a mechanism involving aryl and alkyl radical intermediates.
We report a uniquely high-yielding, general, and practical ortho bromination and iodination reaction of different classes of aromatic compounds. This reaction occurs by Rh(III)-catalyzed C-H bond activation methodology and is therefore the first example of the application of this cationic catalyst for C-Br and C-I bond formation.
Nickel-Mediated Synthesis of Isoindolinones at Room Temperature
This communication describes a method for the Ni(cod)(2)-mediated intramolecular arylation of alkyl C-H bonds adjacent to the nitrogen atom in benzamide substrates. The transformation proceeds at room temperature and exhibits selectivity for functionalization of more substituted C-H bonds. The yields of the desired isoindolinone products are higher with benzamide substrates containing tertiary alkyl groups on the nitrogen atom than with those bearing primary or secondary alkyls. The results described herein suggest a mechanism involving radical intermediates for these reactions.