1.1: tetrakis(triphenylphosphine) palladium(0) / tetrahydrofuran; water / 3.33 h / 20 °C / Inert atmosphere 2.1: diethyl ether / 0.25 h / 0 °C / Inert atmosphere 3.1: toluene / 6 h / Inert atmosphere; Reflux 4.1: tetrabutyl ammonium fluoride / tetrahydrofuran / Inert atmosphere 5.1: lithium hydroxide hydrate / tetrahydrofuran / 1.5 h / Inert atmosphere 6.1: pyridine / toluene / 2.5 h / Inert atmosphere; Reflux 7.1: diethyl ether / 0.33 h / 0 °C / Inert atmosphere 8.1: 1,8-diazabicyclo[5.4.0]undec-7-ene / dichloromethane / 4 h / 20 °C / Inert atmosphere 9.1: Cu(I)CN / tetrahydrofuran / 0.5 h / -78 °C / Inert atmosphere 9.2: 0.75 h / -78 °C / Inert atmosphere 10.1: dimethylsulfide; oxygen; ozone / methanol; dichloromethane / 2 h / -116 - 20 °C / Inert atmosphere 11.1: diethyl ether / 0 °C / Inert atmosphere 12.1: potassium hexamethylsilazane / tetrahydrofuran / 0.25 h / -78 °C / Inert atmosphere 12.2: 1.5 h / -78 - 0 °C / Inert atmosphere 13.1: triethylsilane; tetrakis(triphenylphosphine) palladium(0); lithium chloride / N,N-dimethyl-formamide / 2 h / 55 °C / Inert atmosphere 14.1: lithium hydroxide hydrate / tetrahydrofuran / 10 h / 0 - 20 °C / Inert atmosphere 15.1: trifluoroacetic acid / tetrahydrofuran; dichloromethane / 10 h / Inert atmosphere View Scheme

triethylsilane; tetrakis(triphenylphosphine) palladium(0)

1: N-Boc-4-oxo-L-proline methyl ester With sodium hexamethyldisilazane in tetrahydrofuran T=-78°C; 0.333333 h; 2: N,N-bis(trifluoromethanesulfonyl)aniline in tetrahydrofuran T=-78°C; 3 h;

1: N-Boc-4-oxo-L-proline methyl ester With sodium hexamethyldisilazane in tetrahydrofuran T=-78°C; 0.5 h; 2: N,N-diphenyltrifluoromethanesulfonamide in tetrahydrofuran T=-78°C; 4 h;

lithium hexamethyldisilazane in tetrahydrofuran T=-78 - -20°C;

1: 99 percent / Et3N / CH2Cl2 / 4 h / 0 °C 2: 91 percent / (COCl)2; Et3N; DMSO / CH2Cl2 / -40 - 20 °C 3: 89 percent / lithium bis(trimethylsilyl)amide / tetrahydrofuran / -78 - -20 °C View Scheme

1: 91 percent / (COCl)2; Et3N; DMSO / CH2Cl2 / -40 - 20 °C 2: 89 percent / lithium bis(trimethylsilyl)amide / tetrahydrofuran / -78 - -20 °C View Scheme

1: 99 percent / Et3N / CH2Cl2 / 4 h / 0 °C 2: 91 percent / (COCl)2; Et3N; DMSO / CH2Cl2 / -40 - 20 °C 3: 89 percent / lithium bis(trimethylsilyl)amide / tetrahydrofuran / -78 - -20 °C View Scheme

1.1: thionyl chloride / Inert atmosphere 2.1: Inert atmosphere 3.1: triethylamine / Inert atmosphere 4.1: pyridinium chlorochromate / Inert atmosphere 5.1: sodium hexamethyldisilazane / tetrahydrofuran / 0.5 h / -78 °C / Inert atmosphere 5.2: 1.5 h / -78 - 0 °C / Inert atmosphere View Scheme

1.1: Inert atmosphere 2.1: triethylamine / Inert atmosphere 3.1: pyridinium chlorochromate / Inert atmosphere 4.1: sodium hexamethyldisilazane / tetrahydrofuran / 0.5 h / -78 °C / Inert atmosphere 4.2: 1.5 h / -78 - 0 °C / Inert atmosphere View Scheme