Copper-Catalyzed Oxidative Dearomatization/Spirocyclization of Indole-2-Carboxamides: Synthesis of 2‑Spiro-pseudoindoxyls

A copper-catalyzed oxidative dearomatization/spirocyclization of indole-2-carboxamides using <i>tert</i>-butyl hydroperoxide (TBHP) as the oxidant has been developed that provides rapid and efficient access to C2-spiro-pseudoindoxyls. Two of the sp² C–H bonds are functionalized during the reaction process, and the reaction likely proceeds via the formation of a highly reactive 3<i>H</i>-indol-3-one intermediate followed by aromatic electrophilic substitution with the <i>N</i>-aryl ring of the amide moiety

Transition-Metal-Free Aminoacylation of Ynones with Amides: Synthesis of 3‑Carbonyl-4-quinolinones or Functionalized Enaminones

A transition-metal-free tandem process for the synthesis of substituted quinolin-4­(1<i>H</i>)-ones or enaminones is presented. A base-promoted insertion of ynones into the C–N σ-bond of amides is the key step in this process, which provides the corresponding aminoacylation products in good to high yields. Quinolin-4­(1<i>H</i>)-ones are selectively formed via the subsequent N-cyclization pathway in the cases of ynones bearing an <i>ortho</i>-bromo-substituted aryl ring. Easily accessible starting materials and high atom economy make this procedure attractive

PBr₃‑Mediated Cyclization of 1,7-Diyn-3,6-bis(propargyl carbonate)s: Synthesis of 5‑Bromotetracenes

A new and straightforward method for the synthesis of 5-bromotetracenes through PBr₃-mediated cyclization of 1,7-diyn-3,6-bis­(propargyl carbonate)­s has been developed. This method offers several advantages such as easily accessible starting materials, high efficiency, and wide functional group compatibility. In addition, chloro- and iodo-substituted tetracenes were also synthesized using appropriate halogenating reagents. The utility of the 5-bromotetracene products has been illustrated by their efficient transformations through various palladium-catalyzed cross-coupling reactions

PBr₃‑Mediated Cyclization of 1,7-Diyn-3,6-bis(propargyl carbonate)s: Synthesis of 5‑Bromotetracenes

A new and straightforward method for the synthesis of 5-bromotetracenes through PBr₃-mediated cyclization of 1,7-diyn-3,6-bis­(propargyl carbonate)­s has been developed. This method offers several advantages such as easily accessible starting materials, high efficiency, and wide functional group compatibility. In addition, chloro- and iodo-substituted tetracenes were also synthesized using appropriate halogenating reagents. The utility of the 5-bromotetracene products has been illustrated by their efficient transformations through various palladium-catalyzed cross-coupling reactions