1: 92 percent / pyridine / CH2Cl2 / 12 h / Ambient temperature 2: 1 M BBr3 / 1.) CH2Cl2, -78 deg C, 1 h 2.) CH2Cl2, -78 deg C to RT, 1 h View Scheme

With  lithium diisopropyl amide  1.) THF, -78 deg C, 1 h, 2.) THF, from -78 deg C to RT, 1 h;  Yield given. Multistep reaction;