perchloric acid in diethyl ether 1 h; Ambient temperature;

1.1: LHMDS / tetrahydrofuran / 0.5 h / -78 °C 1.2: tetrahydrofuran / 0.5 h / -78 °C 2.1: NaHCO3; N-bromosuccinimide / tetrahydrofuran / 5 h / -78 - 20 °C 3.1: 5.2 g / aq. NH4Cl / tetrahydrofuran / 16 h / 20 °C View Scheme

1: 1.) n-BuLi / 1.) THF, hexane, room temperature, 1 h, 2.) room temperature, overnight 2: perbenzoic acid / CH2Cl2 / 24 h / 0 - 5 °C View Scheme