Diazotization of sulfanilamide (I), followed by treatment of the resultant diazonium salt with potassium cyanide/copper sulfate under Sandmeyer conditions, leads to nitrile (II). Stephen reduction of (II) with Raney nickel alloy in 75% aqueous formic acid gives the benzaldehyde (III), which is further reduced to the benzyl alcohol (IV) using NaBH4 in ethanol. Treatment of alcohol (IV) with PBr3 provides the benzyl bromide (V). This is then subjected to Arbuzov reaction with triethyl phosphite to produce phosphonate (VI). Finally, Wittig-Horner condensation of (VI) with 4-fluorobenzaldehyde (VII) furnishes the target stilbene derivative.