Friedel–Crafts reactions of n-alkenoic acids and ω-chloroalkanoic acids

The Friedel–Crafts reactions between benzene and pent-2-enoic, pent-3-enoic, pent-4-enoic, 5-chloropentanoic, non-2-enoic, non-8-enoic, and 9-chlorononanoic acid are reported. The nature of the products obtained in the reactions of the alkenoic acids were shown to be dependent on the initial position of the double bond. A rationalisation of these observations is presented. New syntheses of non-8-enoic and 9-chlorononanoic acid are reported together with syntheses of the phenylnonanoic acids, 3-hexylindan-1-one, and 4-pentyl-1-tetralone.