Expedient synthesis of indoles from N-Boc arylhydrazines

Intramolecular Fischer Indole Synthesis and its Combination with an Aromatic [3,3]‐Sigmatropic Rearrangement for the Preparation of Tricyclic Benzo[cd]indoles

“…Our continuing interest in exploring the synthetic application of aryl hydrazides led us to envisage that an intramolecular Fischer indole synthesis could provide expedient access to tricyclic benzo[ cd ]indole systems. As depicted in Scheme , aryl hydrazide 9 with the carbonyl group attached to the meta position may cyclize into tricyclic benzo[ cd ]indole 11 after the hydrazone intermediate 10 is formed 4a. 5, 14…”

SBA‐15‐Pr‐SO3H catalyzed one‐pot synthesis of indole derivatives via Fischer indole pathway

“…Also, indole alkaloid marine natural products have attracted lots of attention in the development of new drug leads for the control of cancer, parasitic, and neurological diseases. Among various methods for the preparation of indoles, Fischer indole method has been one of the most powerful approaches [7][8][9][10][11] and a wide spectrum of methodologies based on the efficient catalysts including Brønsted acids (H 2 SO 4 , HCl, PPA, AcOH, and TsOH), Lewis acids (ZnCl 2 , TiCl 4 ), solid acids (zeolite and montmorillonite clay), [12][13][14][15][16][17] heteropolyacids, [18] ionic liquids, [19,20] and ceric ammonium nitrate (CAN) [21] have been reported. Among various methods for the preparation of indoles, Fischer indole method has been one of the most powerful approaches [7][8][9][10][11] and a wide spectrum of methodologies based on the efficient catalysts including Brønsted acids (H 2 SO 4 , HCl, PPA, AcOH, and TsOH), Lewis acids (ZnCl 2 , TiCl 4 ), solid acids (zeolite and montmorillonite clay), [12][13][14][15][16][17] heteropolyacids, [18] ionic liquids, [19,20] and ceric ammonium nitrate (CAN) [21] have been reported.…”

“…[6] In this regard, numerous methods have been developed for the synthesis of indoles and more efficient and straightforward synthetic strategies are still in high demand due to their importance in material sciences and versatile therapeutic applications. Among various methods for the preparation of indoles, Fischer indole method has been one of the most powerful approaches [7][8][9][10][11] and a wide spectrum of methodologies based on the efficient catalysts including Brønsted acids (H 2 SO 4 , HCl, PPA, AcOH, and TsOH), Lewis acids (ZnCl 2 , TiCl 4 ), solid acids (zeolite and montmorillonite clay), [12][13][14][15][16][17] heteropolyacids, [18] ionic liquids, [19,20] and ceric ammonium nitrate (CAN) [21] have been reported.…”

Palladium- and Copper-Catalyzed Aryl Halide Amination, Etherification and Thioetherification Reactions in the Synthesis of Aromatic Heterocycles

“…Cho and Lim reported a related procedure, in which N-Boc arylhydrazines were employed in Fischer cyclizations. 26 The required N-Boc arylhydrazines were prepared using palladium-catalyzed amination chemistry, but in these cases were isolated before indole formation.…”