Metal‐Free Arylation‐Lactonization Sequence of γ‐Alkenoic Acids Using Anilines as Aryl Radical Precursors

Abstract

The presence of salicylic acid (10 mol‐%) and H2O (10 equiv.) significantly improves the arylation‐lactonization sequence of γ‐alkenoic acids with in situ formed diazonium salts (from bench stable anilines). The reaction is finished in less than 5 h without thermal or photochemical activation, giving access to a variety of γ,γ‐disubstituted butyrolactones. The protocol is user‐friendly and can be used at gram‐scale or adapted to transform alkenols into phthalanes. Control experiments revealed that aryl radicals participate in the reaction and a plausible mechanism is proposed to include this and other mechanistic investigations, for the catalyzed and the background reaction.