Zinc‐Mediated Carbamoyl Amination of Alkylidenecyclopropane‐Tethered Carbamoyl Chlorides: Synthesis of Functionalized 2‐Quinolones

Abstract

The transition metal catalyzed cyclization of alkene‐tethered carbamoyl chloride has now emerged as a vital tool to construct oxindoles bearing all carbon quaternary centers. However, most of these reactions proceed via carbometalation‐initiated 5‐exo‐trig cyclization followed by nucleophilic trapping of the resulting σ alkyl‐metal species to achieve diverse functionalized oxindoles. The 6‐endo‐trig type cyclization of alkene‐tethered carbamoyl chloride has been rarely reported. Herein, a zinc‐mediated carbamoyl amination of alkylidenecyclopropane‐tethered carbamoyl chlorides with anilines for the synthesis of functionalized 2‐quinolones was developed. A range of different substituted 2‐quinolones were prepared in 65‐89% yields from alkylidenecyclopropane‐tethered carbamoyl chlorides and aniline derivatives using Zn/TMSCl system.