Ring Expansion via Palladium‐Catalyzed Aryne Insertion into C−C Bonds of Benzocyclobutenones

Abstract Insertion of arynes into cyclic C−C bonds provides a straightforward approach for ring expansion with an ortho ‐phenylene moiety; however, the current scope of substrates has been restricted to enolizable ketones. Here we report the first example of aryne‐insertion into non‐enolizable ketones through Pd‐catalyzed C−C bond activation of benzocyclobutenones. 2‐Haloaryl boronates were employed as an unconventional aryne precursor. The reaction shows a wide substrate scope and high functional group tolerance. The mechanistic studies reveal an interesting dual role of the Pd catalyst for both aryne generation and C−C bond activation.