1: 47 percent / Et3N / tetrahydrofuran / 1 h / 20 °C 2: 1.) N-chlorosuccinimide, triethylamine; 2.) DDQ, Et3N / 1.) methylene chloride, 20 deg C, 30 min; 2.) methylene chloride, 20 deg C, 90 min 3: 85 percent / trifluoroacetic acid / 1 h / 20 °C 4: 82 percent / chlorobenzene / 4 h / 131 °C 5: LiOH View Scheme

1: 47 percent / Et3N / tetrahydrofuran / 1 h / 20 °C 2: 1.) N-chlorosuccinimide, triethylamine; 2.) DDQ, Et3N / 1.) methylene chloride, 20 deg C, 30 min; 2.) methylene chloride, 20 deg C, 90 min 3: 85 percent / trifluoroacetic acid / 1 h / 20 °C 4: 82 percent / chlorobenzene / 4 h / 131 °C View Scheme