最近,水性胶束介质中的光催化为激活强碳卤键开辟了广阔的途径。然而,到目前为止,它主要探索了强烈的还原条件,将可用的化学空间限制为自由基或阴离子反应性。在这里,我们展示了一种可控的光催化策略,该策略通过自由基或阳离子途径引导氯化苯甲酰胺的反应,从而实现化学发散的 C-H 芳基化或N-脱烷基化。该催化系统在温和的条件下运行,亚甲基蓝作为光催化剂,蓝色 LED 作为光源。介绍了决定底物反应性、选择性和初步机理研究的因素。
Photocatalysis in aqueous micellar media has recently opened wide avenues to activate strong carbon–halide bonds. So far, however, it has mainly explored strongly reducing conditions, restricting the available chemical space to radical or anionic reactivity. Here, we demonstrate a controllable, photocatalytic strategy that channels the reaction of chlorinated benzamides via either a radical or a cationic
最近,水性胶束介质中的光催化为激活强碳卤键开辟了广阔的途径。然而,到目前为止,它主要探索了强烈的还原条件,将可用的化学空间限制为自由基或阴离子反应性。在这里,我们展示了一种可控的光催化策略,该策略通过自由基或阳离子途径引导氯化苯甲酰胺的反应,从而实现化学发散的 C-H 芳基化或N-脱烷基化。该催化系统在温和的条件下运行,亚甲基蓝作为光催化剂,蓝色 LED 作为光源。介绍了决定底物反应性、选择性和初步机理研究的因素。
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.
radical-mediated intramolecular coupling of two C–H bonds of N,N-diisopropyl benzamides was developed. The reactions can proceed in moderate to high yield and with excellent chemoselectivity. A reaction sequence of the formation of an alkyl radical via oxidative cleavage of alkyl C–H bond and the formation of lactam ring via intramolecular homolytic aromatic substitution was proposed.
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.