1: 30percent aq.H2O2, LiOH*H2O / tetrahydrofuran / 3 h / Ambient temperature 2: BH3*THF / 4 h / Ambient temperature 3: TFA / CH2Cl2 / 3 h / Ambient temperature View Scheme

1: 30percent aq.H2O2, LiOH*H2O / tetrahydrofuran / 3 h / Ambient temperature 2: BH3*THF / 4 h / Ambient temperature 3: TFA / CH2Cl2 / 3 h / Ambient temperature 4: 1.) NaHMDS, 3.) Et3N, DMAP 5: DBU / toluene / 1.5 h / 80 °C View Scheme