1: CsF/2-bromopyridiniumtetrafluoroborate / CH2Cl2 2: Bu4NF / tetrahydrofuran / 0.5 h / 0 °C 3: 50 percent / 1.) 2,4,6-trichlorobenzoyl chloride (TCBACl), NEt3; 2.) 4-(dimethylamino)pyridine (DMAP) / 1.) THF; 2.) PhCH3, 110 deg C 4: pyridinium p-toluenesulfonate (PPTS) / methanol / 50 °C View Scheme

PMDBD in dichloromethane

in dichloromethane

1: 80 percent / dicyclohexylcarbodiimide (DCC), 4-(dimethylamino)pyridine (DMAP) / CH2Cl2; dimethylformamide 2: 75 percent / 3,3,6,9,9-pentamethyl-2,10-diazabicyclo<4.4.0>-1-decene / CH2Cl2 View Scheme

1: 87 percent / Dimethylaminopyridine / tetrahydrofuran / 18 h / Ambient temperature 2: 17 percent / CCl4 / 23 h / Heating View Scheme

1: 80 percent / dicyclohexylcarbodiimide (DCC), 4-(dimethylamino)pyridine (DMAP) / CH2Cl2; dimethylformamide 2: 75 percent / 3,3,6,9,9-pentamethyl-2,10-diazabicyclo<4.4.0>-1-decene / CH2Cl2 View Scheme

in tetrachloromethane 23 h; Heating; Title compound not separated from byproducts;

1: 2M NaOH / 2 h / Ambient temperature 2: 4-(dimethylamino)-pyridine, dicyclohexylcarbodiimide / dimethylformamide; CH2Cl2 / 1.) 0 deg C, 5 min, RT, 3 h 3: 73 percent / Eschenmoser's base / CH2Cl2 / 3 h / 0 °C View Scheme