acetic anhydride; triethylamine; zinc 1.) CH2Cl2, 40 deg C, 2 h, 2.) DMF, 50 deg C, 0.5 h; Multistep reaction;

1: 1.) Ac2O, Et3N, 2.) Zn / 1.) CH2Cl2, 40 deg C, 2 h, 2.) DMF, 50 deg C, 0.5 h 2: NaNH2, t-BuOH / toluene; benzene / 1 h / Ambient temperature View Scheme