Palladium-catalyzed reductive cyclization of ortho-vinyl benzoic acids to access 1-indanones

1-Indanones represent a significant class of organic compounds commonly found in many bioactive and functional materials. In this work, we reported an efficient method for their preparation. Mediated by a palladium catalyst, ortho-vinyl benzoic acids could undergo reductive cyclization in the presence of readily available formic acid, producing the corresponding 1-indanones in good to high yields. It is worth noting that high functional group tolerance was demonstrated. In addition, this reaction was easily scaled up. Mechanistic studies show that this reaction would be a tandem process involving cyclization, forming 1-indenones, and subsequent reduction with formic acid. We anticipate that this new reaction would find potential applications in organic synthesis.