Pd/C-Catalyzed Reductive Formylation of Indoles and Quinolines Using Formic Acid

Abstract

A two-step, one-pot domino reaction methodology was developed to synthesize a variety of N-formylindolines and Nformyltetrahydroquinolines from the corresponding indoles and quinolines. In the first step, the heterocyclic compounds are reduced to the corresponding dihydro or tetrahydro products by a Pd/C-catalyzed transfer hydrogenation using formic acid as a hydrogen donor. In the second step, nitrogen is formylated by formic acid to afford the final products in very good isolated yields.

Metal‐Free N‐Doped Carbon Catalyst Derived from Chitosan for Aqueous Formic Acid‐Mediated Selective Reductive Formylation of Quinoline and Nitroarenes

“…The selective reduction is widespread, [15][16][17] but one-pot reductive N-formylation remains challenging. [18,19] Heterogeneous catalysts, including monometallic and bimetallic catalysts, are extensively used to synthesize these scaffolds. [20][21][22] In recent times, efforts have been made to replace noble metals with cheap transition metals for the selective reductive N-formylation of quinoline and nitroarene.…”

“…The selective reduction and reductive N ‐formylation of nitroaromatics is a fascinating protocol as they constitute the fundamental and essential transformation of chemical and pharmaceutical industries. The selective reduction is widespread, [15–17] but one‐pot reductive N ‐formylation remains challenging [18,19] …”

Metal-Free N-Formylation of Amines Using Carbohydrates as C1 Synthon via C–C Bond Cleavage

“…51, 142.25, 129.71, 126.53, 122.48, 32.17. This is a known compound, and the spectroscopic data agree with the literature. 91 The crude product was purified by column chromatography on silica gel (EtOAc/hexane 1.5: 8.5) to give 3ac as a brown colored liquid; yield: 152 mg (94%).…”