1: 91 percent / triethylamine, H2 / Pd/C / acetone / 760 Torr / Ambient temperature 2: 1) toluene-p-sulfonic acid hydrate, 2) HBr gas / 1) CH2Cl2, methanol, 40 min, 2) CH2Cl2 3: 1)trifluoroacetic acid 2) HBr/acetic acid / 1) 5 min 2) 1h 4: 1) copper(II) acetate 2) trifluoroacetic acid, conc. sulfuric acid / 1) dimethylformamide, 160deg C, 4 min 2) 45 min View Scheme

sulfuric acid; copper diacetate; trifluoroacetic acid 1) dimethylformamide, 160deg C, 4 min 2) 45 min; Yield given. Multistep reaction;

1: 1)trifluoroacetic acid 2) HBr/acetic acid / 1) 5 min 2) 1h 2: 1) copper(II) acetate 2) trifluoroacetic acid, conc. sulfuric acid / 1) dimethylformamide, 160deg C, 4 min 2) 45 min View Scheme

1: 1) toluene-p-sulfonic acid hydrate, 2) HBr gas / 1) CH2Cl2, methanol, 40 min, 2) CH2Cl2 2: 1)trifluoroacetic acid 2) HBr/acetic acid / 1) 5 min 2) 1h 3: 1) copper(II) acetate 2) trifluoroacetic acid, conc. sulfuric acid / 1) dimethylformamide, 160deg C, 4 min 2) 45 min View Scheme

1: 1) toluene-p-sulfonic acid hydrate, 2) HBr gas / 1) CH2Cl2, methanol, 40 min, 2) CH2Cl2 2: 1)trifluoroacetic acid 2) HBr/acetic acid / 1) 5 min 2) 1h 3: 1) copper(II) acetate 2) trifluoroacetic acid, conc. sulfuric acid / 1) dimethylformamide, 160deg C, 4 min 2) 45 min View Scheme