Newradical annulation reactions are described involving addition of cyano-substituted alkyl and sulfanyl radicals to aromatic isonitriles. The tandemcyclisation of the resulting imidoyl radicals onto the cyano group affords cyclopenta- and thienoquinoxalines, respectively. The intervention of the isonitriles in the aromatisation process of the cyclohexadienyl radicals is discussed, as well as the
An umpolung strategy for rapid access to thermally activated delayed fluorescence (TADF) materials based on phenazine
作者:Huaxing Zhang、Qiang Guo、Hu Cheng、Chunhao Ran、Di Wu、Jingbo Lan
DOI:10.1039/d1cc06705b
日期:——
radical nucleophilic addition/rearrangement of 2-aryl diazaboroles has been accomplished for the first time to construct phenazine structures. This protocol is an umpolung strategy based on the classical electrophilic mechanism, and therefore, a reversed regioselectivity was observed, which provides an opportunity to prepare sterically hindered phenazines. The resulting thermally activated delayed fluorescence
A novel cascade radicalreaction is described involving aryl isothiocyanates and 2-cyanoaryl radicals. The mechanism entails the formation of an alpha-(arylthio)imidoyl radical, a 5-exo-dig cyclization onto a cyano group, and a final 6-membered ring closure of an iminyl radical. The competitive 5-membered spiro-cyclization of the iminyl, leading to an isomeric product, was only observed in the case
DABCO-Catalyzed DMSO-Promoted Sulfurative 1,2-Diamination of Phenylacetylenes with Elemental Sulfur and <i>o</i>-Phenylenediamines: Access to Quinoxaline-2-thiones
The oxidative amination of alkynes typically requires transition metal catalysts and strong oxidants. Herein, we alternatively utilize DABCO as a sulfur-activating catalyst to achieve the sulfurative 1,2-diamination of phenylacetylenes with elemental sulfur and o-phenylenediamines. DMSO was found to be particularly suitable for use as a terminaloxidant for this three-component process. A mechanistic