1: 2,2-difluoro-1,3-benzodioxole With sec.-butyllithium in tetrahydrofuran; cyclohexane T=-75°C; 2 h; 2: carbon dioxide in tetrahydrofuran; cyclohexane T=-78°C; Further stages.;

1.1: 68 percent / diethyl ether / 3 h / 25 °C 2.1: 84 percent / hydroxylamine hydrochloride; sodium acetate trihydrate / methanol / 0.5 h / Heating 3.1: phosphorus pentachloride / benzene / 0.25 h / Heating 3.2: 82 percent / hydrochloric acid / H2O; ethanol / 6 h / Heating View Scheme

thionyl chloride in 1,2-dichloro-ethane; N,N-dimethyl-formamide; toluene

thionyl chloride 2 h; Heating;

in diethyl ether T=25°C; 3 h;

1: 90 percent / boron trifluoride-diethyl etherate / 48 h / 25 °C 2: 56 percent / formamide; sodium methoxide / dimethylformamide / 6 h / 100 °C 3: 91 percent / thionyl chloride / 6 h / Heating View Scheme

boron trifluoride diethyl etherate T=25°C; 48 h;