trifluoroacetic acid in dichloromethane 0.5 h; Ambient temperature;

1: 69 percent / triphenylphosphine; diisopropyl azodicarboxylate / tetrahydrofuran / 72 h / 20 °C 2: trifluoroacetic acid View Scheme

1: 69 percent / triphenylphosphine; diisopropyl azodicarboxylate / tetrahydrofuran / 72 h / 20 °C 2: trifluoroacetic acid View Scheme

1: 96 percent / CH2Cl2 / 0.5 h 2: 92.9 percent / Et3N / CH2Cl2 / 1 h / 0 °C 3: 1.) NaH / 1.) DMF, RT, 10 min., 2.) DMF, 60 deg C, 16 h 4: 95 percent / TFA / CH2Cl2 / 0.5 h / Ambient temperature View Scheme

1: 1.) NaH / 1.) DMF, RT, 10 min., 2.) DMF, 60 deg C, 16 h 2: 95 percent / TFA / CH2Cl2 / 0.5 h / Ambient temperature View Scheme