1: 3-bromo-pyridine With boron trifluoride diethyl etherate in tetrahydrofuran T=0°C; 0.25 h; Inert atmosphere; 2: isopropylmagnesium chloride lithium chloride complex in tetrahydrofuran T=-50°C; 0.5 h; Inert atmosphere; 3: With chloranil in tetrahydrofuran T=20°C; 2 h; Inert atmosphere; regioselective reaction;

1: 1.) CuI, (CH3)2S / 1.) THF, -20 deg C, 5 min, 2.) THF, a) -20 deg C, 15 min, b) RT, 15 min 2: o-chloranil / acetic acid / 8 h / Ambient temperature View Scheme