1: (2α,3aβ,7aβ)-octahydro-1H-indole-2-carboxylic acid With chloro-trimethyl-silane; 1,1,1,3,3,3-hexamethyl-disilazane in acetonitrile T=25 - 30°C; 3 - 3.5 h; Heating / reflux; 2: With triethylamine in dichloromethane; acetonitrile T=0 - 5°C; 0.0833333 - 0.166667 h; 3: N-[1(S)-ethoxycarbonylbutyl]-(S)-alanine-2'-benzothiazolylthio ester in dichloromethane; acetonitrile T=-20 - 30°C; 16 - 17 h; Product distribution / selectivity;

1: (2α,3aβ,7aβ)-octahydro-1H-indole-2-carboxylic acid With chloro-trimethyl-silane; triethylamine in dichloromethane T=20 - 25°C; 3 h; 2: (S)-N-[(S)-1-(ethoxycarbonyl)butyl]alanine With 1H-imidazole; thionyl chloride in dichloromethane T=-10 - 25°C; 23 h; 3: With sodium hydroxide in dichloromethane; water pH=5 - 6; Product distribution / selectivity;

1: (2α,3aβ,7aβ)-octahydro-1H-indole-2-carboxylic acid With chloro-trimethyl-silane; triethylamine in dichloromethane T=20 - 25°C; 2 h; 2: N-[1(S)-ethoxycarbonyl-1-butyl]-(S)-alanyl chloride hydrochloride in dichloromethane T=-15 - 0°C; 2 h; 3: With sodium hydroxide in dichloromethane; water pH=4.2; Product distribution / selectivity;

1: (2α,3aβ,7aβ)-octahydro-1H-indole-2-carboxylic acid With chloro-trimethyl-silane; triethylamine in dichloromethane T=20 - 25°C; 2 h; 2: N-((S)-1-carbethoxybutyl)-L-alanyl chloride hydrochloride With triethylamine in dichloromethane T=-15°C; 2 h; 3: tert-butylamine in isopropanol acetate Product distribution / selectivity;

1: N-[1(S)-ethoxycarbonyl-1-butyl]-(S)-alanyl chloride hydrochloride With 1H-imidazole in dichloromethane T=-5 - 0°C; 1 h; 2: (2α,3aβ,7aβ)-octahydro-1H-indole-2-carboxylic acid in dichloromethane T=-5 - 25°C; 4.75 h; 3: tert-butylamine in dichloromethane T=10 - 40°C; 1 h; Product distribution / selectivity;

triethylamine in tetrahydrofuran; water T=20°C;