1: 5-(benzyloxy)-4-[(Boc)amino]-5-oxopentanoic acid; diazomethyl-trimethyl-silane in methanol; hexane; dichloromethane T=0°C; 1 h; 2: di-tert-butyl dicarbonate With 4-(N,N-dimethlyamino)pyridine in acetonitrile 24 h;

1: BOC-D-glutamine benzyl ester; diazomethyl-trimethyl-silane in methanol; hexane; dichloromethane T=0°C; 1 h; 2: di-tert-butyl dicarbonate With 4-(N,N-dimethlyamino)pyridine in acetonitrile 24 h;

4-(N,N-dimethlyamino)pyridine in acetonitrile 24 h;

1.1: diisobutylaluminium hydride / toluene; diethyl ether / 0.58 h / -78 - -65 °C 1.2: 0.5 h / -65 - 20 °C 2.1: N,N,N',N'-tetramethylguanidine / toluene / 0.5 h / 0 °C 2.2: 1.5 h / 0 - 20 °C 3.1: 1,4-dioxane; water / 0.25 h / Inert atmosphere 3.2: 6 h / 20 - 35 °C 4.1: hydrogen / palladium 10 on activated carbon / ethanol / 36 h / 2844.39 Torr 5.1: 1-hydroxy-7-aza-benzotriazole; triethylamine; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride / dichloromethane / 1 h View Scheme

1.1: diisobutylaluminium hydride / toluene; diethyl ether / 0.58 h / -78 - -65 °C 1.2: 0.5 h / -65 - 20 °C 2.1: N,N,N',N'-tetramethylguanidine / toluene / 0.5 h / 0 °C 2.2: 1.5 h / 0 - 20 °C 3.1: 1,4-dioxane; water / 0.25 h / Inert atmosphere 3.2: 6 h / 20 - 35 °C 4.1: hydrogen / palladium 10 on activated carbon / ethanol / 36 h / 2844.39 Torr 5.1: 1-hydroxy-7-aza-benzotriazole; triethylamine; 1-ethyl-(3-(3-dimethylamino)propyl)-carbodiimide hydrochloride / dichloromethane / 1 h 6.1: sodium hydride / N,N-dimethyl-formamide; mineral oil / 0.25 h / -35 °C 6.2: 2.5 h / -35 °C 7.1: trifluoroacetic acid / dichloromethane / 0.5 h View Scheme

1.1: diisobutylaluminium hydride / toluene; diethyl ether / 0.58 h / -78 - -65 °C 1.2: 0.5 h / -65 - 20 °C 2.1: N,N,N',N'-tetramethylguanidine / toluene / 0.5 h / 0 °C 2.2: 1.5 h / 0 - 20 °C View Scheme

1: With diisobutylaluminium hydride in diethyl ether T=-78 - -65°C; 0.583333 h; 2: With water in diethyl ether

1.1: diisobutylaluminium hydride / toluene; diethyl ether / 0.58 h / -78 - -65 °C 1.2: 0.5 h / -65 - 20 °C 2.1: N,N,N',N'-tetramethylguanidine / toluene / 0.5 h / 0 °C 2.2: 1.5 h / 0 - 20 °C 3.1: 1,4-dioxane; water / 0.25 h / Inert atmosphere 3.2: 6 h / 20 - 35 °C 4.1: hydrogen / palladium 10 on activated carbon / ethanol / 36 h / 2844.39 Torr View Scheme

1.1: diisobutylaluminium hydride / toluene; diethyl ether / 0.58 h / -78 - -65 °C 1.2: 0.5 h / -65 - 20 °C 2.1: N,N,N',N'-tetramethylguanidine / toluene / 0.5 h / 0 °C 2.2: 1.5 h / 0 - 20 °C 3.1: 1,4-dioxane; water / 0.25 h / Inert atmosphere 3.2: 6 h / 20 - 35 °C View Scheme