tetrabutyl ammonium fluoride in tetrahydrofuran T=20°C;

Au(Ph3P)+NTf2-; toluene-4-sulfonic acid in toluene T=100°C; Hydrohydrazination / Fisher indolization; 2 h; Inert atmosphere; regioselective reaction;

1: 2,6-di-tert-butyl-4-methylphenol; Ti(NEt2)4 / toluene / 24 h / 100 °C 2: ZnCl2 / toluene / 24 h / 100 °C 3: 80 percent / TBAF*3H2O / tetrahydrofuran / 20 °C View Scheme

1.1: diethyl ether / 6 h / 0 - 20 °C 2.1: diethyl ether / 0 °C 3.1: lithium aluminium tetrahydride / tetrahydrofuran / 4 h / 20 °C 4.1: 1H-imidazole / N,N-dimethyl-formamide / 3 h / 0 - 20 °C 5.1: sodium hydride / tetrahydrofuran; mineral oil / 1.25 h / 0 - 20 °C 5.2: 20 °C 6.1: tetrabutyl ammonium fluoride / 24 h View Scheme

1.1: diethyl ether / 0 °C 2.1: lithium aluminium tetrahydride / tetrahydrofuran / 4 h / 20 °C 3.1: 1H-imidazole / N,N-dimethyl-formamide / 3 h / 0 - 20 °C 4.1: sodium hydride / tetrahydrofuran; mineral oil / 1.25 h / 0 - 20 °C 4.2: 20 °C 5.1: tetrabutyl ammonium fluoride / 24 h View Scheme

1.1: lithium aluminium tetrahydride / tetrahydrofuran / 4 h / 20 °C 2.1: 1H-imidazole / N,N-dimethyl-formamide / 3 h / 0 - 20 °C 3.1: sodium hydride / tetrahydrofuran; mineral oil / 1.25 h / 0 - 20 °C 3.2: 20 °C 4.1: tetrabutyl ammonium fluoride / 24 h View Scheme

1.1: 1H-imidazole / N,N-dimethyl-formamide / 3 h / 0 - 20 °C 2.1: sodium hydride / tetrahydrofuran; mineral oil / 1.25 h / 0 - 20 °C 2.2: 20 °C 3.1: tetrabutyl ammonium fluoride / 24 h View Scheme