N-ethyl-N,N-diisopropylamine in acetonitrile T=-15 - -10°C; 5 - 8 h;

N-ethyl-N,N-diisopropylamine in dichloromethane T=-35 - -30°C;

in methanol

1: 4-Nitrobenzyl (2S,4S)-4-(acetylthio)-2-[(dimethylamino)carbonyl]pyrrolidine-1-carboxylate With pyrrolidine in N,N-dimethyl-formamide T=-5 - 0°C; 0.5 h; 2: MAP With N-ethyl-N,N-diisopropylamine in N,N-dimethyl-formamide T=-40 - -35°C; 1 h;

1: 4-nitrobenzyl (4R,5R,6S)-6-[(1R)-1-hydroxyethyl]-4-methyl-3,7-dioxo-1-azabicyclo[3.2.0]-heptane-2-carboxylate With N-ethyl-N,N-diisopropylamine; phosphorochloridic acid diphenyl ester in acetonitrile T=10 - 15°C; 5 h; 2: (2S,4S)-2-dimethylaminocarbonyl-4-mercapto-1-(4-nitrobenzyloxycarbonyl)pyrrolidine With N-ethyl-N,N-diisopropylamine in acetonitrile T=10 - 15°C; 5 - 8 h;

3-chloro-benzenecarboperoxoic acid

1: 90 percent / K2CO3 / acetone / 4 h / Heating 2: 100 percent / NaH / tetrahydrofuran / 2 h / 0 °C 3: 100 percent / H2 / 10percent Pd/C / ethanol / 760 Torr / Ambient temperature 4: Et3N / CH2Cl2 / 1 h 5: CH2Cl2 / 1 h 6: 86 percent / anisole, TiCl4 / CH2Cl2 / 1 h / 0 °C 7: 93 percent / γ-collidine / dimethylformamide / 1.5 h / 65 °C 8: 98 percent / Et3N / toluene / 5 h / Ambient temperature 9: 1.) NaH, 2.) benzyl bromide / 1.) THF, toluene, -20 deg C, 1 h, 2.) THF, toluene, -20 deg C, 2 h 10: DBU / toluene; tetrahydrofuran / 2 h 11: 89 percent / phosphate buffer pH 3 / 2.5 h / Ambient temperature View Scheme

1: 100 percent / NaH / tetrahydrofuran / 2 h / 0 °C 2: 100 percent / H2 / 10percent Pd/C / ethanol / 760 Torr / Ambient temperature 3: Et3N / CH2Cl2 / 1 h 4: CH2Cl2 / 1 h 5: 86 percent / anisole, TiCl4 / CH2Cl2 / 1 h / 0 °C 6: 93 percent / γ-collidine / dimethylformamide / 1.5 h / 65 °C 7: 98 percent / Et3N / toluene / 5 h / Ambient temperature 8: 1.) NaH, 2.) benzyl bromide / 1.) THF, toluene, -20 deg C, 1 h, 2.) THF, toluene, -20 deg C, 2 h 9: DBU / toluene; tetrahydrofuran / 2 h 10: 89 percent / phosphate buffer pH 3 / 2.5 h / Ambient temperature View Scheme

1: 100 percent / H2 / 10percent Pd/C / ethanol / 760 Torr / Ambient temperature 2: Et3N / CH2Cl2 / 1 h 3: CH2Cl2 / 1 h 4: 86 percent / anisole, TiCl4 / CH2Cl2 / 1 h / 0 °C 5: 93 percent / γ-collidine / dimethylformamide / 1.5 h / 65 °C 6: 98 percent / Et3N / toluene / 5 h / Ambient temperature 7: 1.) NaH, 2.) benzyl bromide / 1.) THF, toluene, -20 deg C, 1 h, 2.) THF, toluene, -20 deg C, 2 h 8: DBU / toluene; tetrahydrofuran / 2 h 9: 89 percent / phosphate buffer pH 3 / 2.5 h / Ambient temperature View Scheme

1: dirhodium(II) tetraoctanoate / dichloromethane / 7 h / Reflux 2: N-ethyl-N,N-diisopropylamine / 4-(N,N-dimethlyamino)pyridine / dichloromethane / -35 °C 3: N-ethyl-N,N-diisopropylamine / dichloromethane / -35 - -30 °C View Scheme