The Friedel-Crafts reaction of 2-fluorobiphenyl (I) with acetyl chloride (II) by means of AlCl3 in refluxing CS2 gives 4-(2-fluorophenyl)acetophenone (III) (1,2), which by reaction with PCl5 in POCl3 at 60 C is converted into 4-(2-fluorophenyl)-alpha-chlorostyrene (IV). Finally this compound is treadted with NaNH2 in liquid NH3.