1: 1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indole-3-acetic acid With oxalyl dichloride in dichloromethane T=20°C; 2 h; 2: ethanol With triethylamine in dichloromethane 0.5 h;

1: 5-methoxy-2-methyl-1H-indole-3-acetic acid ethyl ester With potassium tert-butylate in tetrahydrofuran T=-78°C; 1 h; 2: 4-chloro-benzoyl chloride in tetrahydrofuran 3 h;

triethylamine in dichloromethane T=0 - 5°C; Esterification; 0.5 h;

1.1: n-butyllithium / tetrahydrofuran; hexane / 0.5 h / 0 - 20 °C 1.2: 0.5 h 1.3: 24 h 2.1: potassium tert-butylate / tetrahydrofuran / 1 h / -78 °C 2.2: 3 h View Scheme

1.1: [{(η5-C5Me5)RhCl}2(μ-Cl)2]; silver hexafluoroantimonate; copper diacetate; silver carbonate / 1,4-dioxane / 24 h / 110 °C / |Schlenk technique; |Inert atmosphere 2.1: potassium hydroxide / tetrahydrofuran; ethanol / |Reflux 3.1: n-butyllithium / tetrahydrofuran; hexane / 0.5 h / 0 - 20 °C 3.2: 0.5 h 3.3: 24 h 4.1: potassium tert-butylate / tetrahydrofuran / 1 h / -78 °C 4.2: 3 h View Scheme

1.1: potassium hydroxide / tetrahydrofuran; ethanol / |Reflux 2.1: n-butyllithium / tetrahydrofuran; hexane / 0.5 h / 0 - 20 °C 2.2: 0.5 h 2.3: 24 h 3.1: potassium tert-butylate / tetrahydrofuran / 1 h / -78 °C 3.2: 3 h View Scheme

lithium hydroxide hydrate in water T=25°C; 6 h;