trifluoroacetic acid in dichloromethane T=20°C; 2 h;

1.1: 4-(N,N-dimethlyamino)pyridine; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride; (R)-N-(tert-butoxycarbonyl)proline / 1,2-dichloro-ethane / 0 - 20 °C 2.1: sodium hydride / tetrahydrofuran / 0.5 h / 0 °C 2.2: Reflux 3.1: 4-(N,N-dimethlyamino)pyridine / N,N-dimethyl-formamide / 20 °C 4.1: sodium acetate / dichloro(1,1'-bis(diphenylphosphanyl)ferrocene)palladium(II) dichloromethane adduct / N,N-dimethyl-formamide / 90 °C 5.1: water; lithium hydroxide hydrate / tetrahydrofuran / 20 °C 5.2: pH 5 6.1: N-ethyl-N,N-diisopropylamine; HATU / N,N-dimethyl-formamide / 0.5 h / 20 °C 6.2: 0.5 h / 20 °C 7.1: trifluoroacetic acid / dichloromethane / 2 h / 20 °C View Scheme

1.1: sodium hydride / tetrahydrofuran / 0.5 h / 0 °C 1.2: Reflux 2.1: 4-(N,N-dimethlyamino)pyridine / N,N-dimethyl-formamide / 20 °C 3.1: sodium acetate / dichloro(1,1'-bis(diphenylphosphanyl)ferrocene)palladium(II) dichloromethane adduct / N,N-dimethyl-formamide / 90 °C 4.1: water; lithium hydroxide hydrate / tetrahydrofuran / 20 °C 4.2: pH 5 5.1: N-ethyl-N,N-diisopropylamine; HATU / N,N-dimethyl-formamide / 0.5 h / 20 °C 5.2: 0.5 h / 20 °C 6.1: trifluoroacetic acid / dichloromethane / 2 h / 20 °C View Scheme

1.1: 4-(N,N-dimethlyamino)pyridine / N,N-dimethyl-formamide / 20 °C 2.1: sodium acetate / dichloro(1,1'-bis(diphenylphosphanyl)ferrocene)palladium(II) dichloromethane adduct / N,N-dimethyl-formamide / 90 °C 3.1: water; lithium hydroxide hydrate / tetrahydrofuran / 20 °C 3.2: pH 5 4.1: N-ethyl-N,N-diisopropylamine; HATU / N,N-dimethyl-formamide / 0.5 h / 20 °C 4.2: 0.5 h / 20 °C 5.1: trifluoroacetic acid / dichloromethane / 2 h / 20 °C View Scheme

1.1: sodium acetate / dichloro(1,1'-bis(diphenylphosphanyl)ferrocene)palladium(II) dichloromethane adduct / N,N-dimethyl-formamide / 90 °C 2.1: water; lithium hydroxide hydrate / tetrahydrofuran / 20 °C 2.2: pH 5 3.1: N-ethyl-N,N-diisopropylamine; HATU / N,N-dimethyl-formamide / 0.5 h / 20 °C 3.2: 0.5 h / 20 °C 4.1: trifluoroacetic acid / dichloromethane / 2 h / 20 °C View Scheme

1.1: water; lithium hydroxide hydrate / tetrahydrofuran / 20 °C 1.2: pH 5 2.1: N-ethyl-N,N-diisopropylamine; HATU / N,N-dimethyl-formamide / 0.5 h / 20 °C 2.2: 0.5 h / 20 °C 3.1: trifluoroacetic acid / dichloromethane / 2 h / 20 °C View Scheme

1.1: N-ethyl-N,N-diisopropylamine; HATU / N,N-dimethyl-formamide / 0.5 h / 20 °C 1.2: 0.5 h / 20 °C 2.1: trifluoroacetic acid / dichloromethane / 2 h / 20 °C View Scheme