1: 2.) HCl / 1.) CH2Cl2, room temp., 12 h; 2.) 12 h, ether 2: 1.) BBr3; 2.) MeOH, H2SO4 (96percent) / 1.) CH2Cl2, room temp., 140 h; 2.) reflux, 48 h 3: 93 percent / benzoyl t-butyl nitroxide / methanol; CHCl3 / 16 h / Ambient temperature View Scheme

1: CH2Cl2 2: 21 percent / BBr3 / CH2Cl2 3: 93 percent / tBuN(O)COPh / CH2Cl2; methanol View Scheme

Multi-step reaction with 3 steps 1: NaOMe / methanol / -10 °C2: xylene / Heating3: HCl / methanol / Heating