1.1: Mg / tetrahydrofuran / 1.5 h / Heating 1.2: 78 percent / tetrahydrofuran; benzene / 0 - 22 °C 2.1: 98 percent / KOH / ethanol / 24 h / Heating 3.1: Et3N; ethyl chloroformate / acetone / 0.5 h / -15 °C 3.2: 96 percent / NaN3 / acetone; H2O / 1.5 h / -15 °C 4.1: 96 percent / BBr3 / CH2Cl2 / 0 - 22 °C View Scheme

1.1: Et3N; ethyl chloroformate / acetone / 0.5 h / -15 °C 1.2: 96 percent / NaN3 / acetone; H2O / 1.5 h / -15 °C 2.1: 96 percent / BBr3 / CH2Cl2 / 0 - 22 °C View Scheme

1.1: NaH / dimethylformamide 2.1: Mg / tetrahydrofuran / 1.5 h / Heating 2.2: 78 percent / tetrahydrofuran; benzene / 0 - 22 °C 3.1: 98 percent / KOH / ethanol / 24 h / Heating 4.1: Et3N; ethyl chloroformate / acetone / 0.5 h / -15 °C 4.2: 96 percent / NaN3 / acetone; H2O / 1.5 h / -15 °C 5.1: 96 percent / BBr3 / CH2Cl2 / 0 - 22 °C View Scheme

1.1: 98 percent / KOH / ethanol / 24 h / Heating 2.1: Et3N; ethyl chloroformate / acetone / 0.5 h / -15 °C 2.2: 96 percent / NaN3 / acetone; H2O / 1.5 h / -15 °C 3.1: 96 percent / BBr3 / CH2Cl2 / 0 - 22 °C View Scheme

1: n-BuLi / tetrahydrofuran; hexane / 0.17 h / 0 °C 2: 2.) TBAF / 1.) pyridine, 0 deg C, 30 min, RT, 1 h; 2.) pyridine, THF, RT, 7 h 3: K2CO3 / dimethylformamide / 6 h / Ambient temperature 4: 90 percent Spectr. / Pd(OAc)2, bis(2-(diphenylphosphino)phenyl) ether, 4 Angstroem molecular sieves, Et3N, Cs2CO3 / toluene / 18 h / 110 °C 5: aq. HCl / tetrahydrofuran; ethanol / 1 h 6: NH4HCO2 / 20 percent Pd(OH)2/C / tetrahydrofuran; propan-2-ol / 1 h / Heating View Scheme

(R)-1-phenyl-ethyl-amine in isopropyl alcohol 20 h; Ambient temperature;

Fmoc-L-Asn(Trt)-L-Asn(Trt)-NH(CH2)6CONH(CH2)3-silica gel in chloroform

benzylamine; copper dichloride in methanol 48 h; Ambient temperature; Yields of byproduct given;

1.1: N-ethyl-N,N-diisopropylamine / dichloromethane / 1 h / 0 - 20 °C / |Inert atmosphere 2.1: sodium hydride / tetrahydrofuran / 0.25 h / 0 °C / |Inert atmosphere 2.2: 2 h / 20 °C / |Inert atmosphere 3.1: palladium 10 on activated carbon; bis[2-(diphenylphosphino)phenyl] ether; caesium carbonate / toluene / 14 h / 110 °C / |Inert atmosphere 4.1: palladium 10 on activated carbon; hydrogen / ethyl acetate / 3 h / 45 °C / 760.05 Torr 5.1: sulfuric acid / dichloromethane; methanol / 5 h / |Reflux View Scheme

1.1: magnesium / benzene / 1.5 h 1.2: 12 h / 80 °C 2.1: ethanol; potassium hydroxide / 24 h / 80 °C 3.1: triethylamine; methyl chloroformate / acetone / 0.5 h / -15 °C 4.1: sodium azide; water / acetone / 1.5 h / -15 °C 5.1: boron tribromide / dichloromethane / -20 - 0 °C View Scheme