trifluoroacetic acid in dichloromethane 1 h; Ambient temperature;

1: 35 percent / aq. NaOH, Bu4NHSO4 / toluene / 1.) 0 deg C, 10 min, 2.) room temp., 30 min 2: 100 percent / CF3COOH / CH2Cl2 / 1 h / Ambient temperature View Scheme

oxalyl dichloride; N,N-dimethyl-formamide in dichloromethane 1 h; Ambient temperature;