Direct Synthesis of 3‐Aryl Substituted Isocoumarins and Phthalides through Palladium Acetate Catalyzed C(sp2)−H Activation in Ionic Liquids. Issue 65 (19th September 2022)

• Record Type: Journal Article
• Authors: Aloia, Andrea; Casiello, Michele; D'Accolti, Lucia; Fusco, Caterina; Nacci, Angelo; Monopoli, Antonio
• Is Part Of: Chemistry. Volume 28:Issue 65(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-09-19
• Subjects: benzylidenephthalide -- C−H activation -- isocoumarin -- ionic liquid -- palladium catalysis; Chemistry -- Periodicals; 540
• DOI: 10.1002/chem.202202350
• Languages: English
• ISSNs: 0947-6539

Abstract

Abstract: A novel Pd‐catalysed oxidative coupling between benzoic acids and vinylarenes or acrylates to furnish isocoumarins and phthalides is reported. The reaction proceeds smoothly in molten tetrabutylammonium acetate via a selective C−H bond activation, with very low percentage of ligand‐free palladium acetate as the catalyst, under atmospheric pressure of oxygen. Sub‐stoichiometric amount of copper acetate is also required as a reoxidant for the palladium. Abstract : A simple, high‐throughput synthesis of isocoumarins and phthalides is presented. The reaction is carried out in molten tetrabutylammonium acetate (ionic liquid) which allows the use of an amount of palladium acetate from ten to twenty times lower than that of similar protocols in molecular solvents (0.5 % mol). Oxygen is used as a reoxidant for the metal, mediated by copper acetate.