Synthesis of the ortho/meta/para Isomers of Relevant Pharmaceutical Compounds by Coupling a Sonogashira Reaction with a Regioselective Hydration

Aryl ketones substituted in ortho, meta, and para position are prepared by a palladium-catalyzed Sonogashira reaction followed by a regioselective hydration of the so-formed alkyne with triflimidic acid or a gold catalyst, under catalytic conditions. This methodology opens a way to obtain substituted aryl alkyl ketones from readily available starting materials, haloarenes, and terminal alkynes. The syntheses of the different regioisomers of haloperidol, melperone, pipamperone, and ibuprofen are presented. Structure–activity relationships for these compounds are studied with dopaminergic and cyclooxigenase binding assays.