1: 86 percent / N-bromosuccinimide / H2O; acetone / 1.) 0 deg C, 2.) from 0 deg C to room temp., 1 h 2: 94 percent / BBr3 / CH2Cl2 / 7 h / -50 °C 3: 96 percent / 10percent NaOH / tetrahydrofuran / 0.5 h View Scheme