Divergent Synthesis of Quinoline Derivatives via [5+1] Annulation of 2‐Isocyanochalcones with Nitroalkanes

Abstract

An unprecedented substrate‐dependent [5+1] annulation of 2‐isocyanochalcones with nitroalkanes was developed for the efficient synthesis of functionalized quinolines and 3‐nitrodihydroquinolines. This transformation delivers both the aromatic and dihydroquinolines by selectively elimination or retention of the nitro group. Moreover, 3‐nitroquinolines and tricyclic pyrrolo[2,3‐c]quinolines were conveniently constructed from the resulting 3‐nitrodihydroquinolines through a single operation, respectively.magnified image

The Chemistry and Biological Applications of 3H‐Pyrrolo[2,3‐c]quinolines and Marinoquinolines

“…In 2018, Bao and co‐workers showed that their work on [5+1] annulation of 2‐isocyanochalcones with nitroalkanes, used for the synthesis of quinolines and 3‐nitrodihydroquinolines, could also be applied for the synthesis of substituted MQ [44] . The authors then reacted 2‐isocyanochalcones 104 with nitromethane in a DBN‐catalyzed [5+1] annulation to obtain the 3‐nitro‐1,4‐dihydroquinolines 107 in yields varying from 40% to 77%.…”

“…[39] MQ. [44] The authors then reacted 2-isocyanochalcones 104 with nitromethane in a DBN-catalyzed [5 + 1] annulation to obtain the 3-nitro-1,4-dihydroquinolines 107 in yields varying from 40% to 77%.…”

Organocatalyzed Synthesis of Functionalized Quinolines

“…Xu et al . developed a new [5+1] annulation of 2‐isocyanochalcones with nitroalkanes to synthesize functionalized quinolines and 3‐nitrodihydroquinolines in 2018 (Scheme ).…”

“…Xu et al [55] developed an ew [5+ +1] annulation of 2-isocyanochalcones with nitroalkanest os ynthesize functionalized quinolines and 3-nitrodihydroquinolines in 2018 (Scheme 37). This transformation was catalyzed by 2,3,4,6,7,8-hexahydropyrrolo[1,2-a]pyrimidine (DBN) and delivered both the aromatic and dihydroquinolines by selectively elimination or retention of the nitro group.…”

Silver-Catalyzed Nucleophilic Addition of β-Dicarbonyls to Isocyano Group: Facile Access to Indolin-3-ol Derivatives

“…3−8 In 2003, Liu and McWhorter reported an elegant work for the synthesis of 3-substituted 2-aryl-3H-indol-3-ols by the nucleophilic addition of Grignard reagents to 2-aryl-3Hindol-3-ones. 3 Later, copper-catalyzed arylation of indolin-2,3-ones with arylboronic acids 4 and oxidation of 2-aryltryptamine derivatives 5 were well developed for the preparation of indolin-3-ol derivatives. Recently, transition-metal Pd-, 6 Au-, 7 or Ag-catalyzed 8 cyclization of 1-(2-(sulfonylamino)phenyl)prop-2-yn-1-ols has been proven to be an efficient protocol for the assembly of indolin-3-ol derivatives.…”