Alkylation of uracil (I) with propargyl bromide (II) in the presence of DBU affords the N1-alkylated product (III). Palladium-catalyzed coupling of the terminal alkyne (III) with cis-1,2-dichloroethene (IV) furnishes the chlorovinyl adduct (V). Subsequent alkylation at the N3-position of (V) with propargyl bromide (II) and DBU leads to the open-chain enediyne (VI). This is finally cyclized to the target bicyclic compound in the presence of Pd(PPh3)4, CuI and butylamine.