1: Li / liquid ammonia / -60 °C / reduction by alkali metal 2: liquid ammonia / -40 °C View Scheme

in ammonia T=-40°C;

ethyl bromide; chloranil; magnesium 1) THF, 50 deg C, 30 min, 2) benzene, 10 deg C, 3 h; RT, 15 h; Yield given. Multistep reaction. Further byproducts given. Yields of byproduct given;