pyridinium tribromide; triethylamine in dichloromethane T=0°C; 2 h;

in chloroform

1: 1.) NaH / 1.) THF, 0 deg C, 45 min, 2.) THF, RT, 2 h 2: 1.) n-BuLi / 1.) hexane, THF, -78 deg C, 15 min, 2.) hexane, THF, from -78 deg C to RT 3: 1.) boron trifluoride etherate, 2.) Triton B / 1.) CH2Cl2, RT, 2 h, 2.) acetonitrile, methanol View Scheme