Synthesis of Malonate-Substituted Benzocyclobutenes via Palladium-Catalyzed Alkene Difunctionalization

The Pd-catalyzed coupling of 2-vinylphenyl triflates with malonate esters provides malonate-substituted benzocyclobutenes in moderate yield. The reactions proceed via an unprecedented intermolecular <i>anti</i>-nucleopalladation of the 2-vinylphenyl triflate, followed by C-C bond-forming reductive elimination to generate the strained ring. This method provides a concise, three-step route to substituted benzocyclobutenes from commercially available salicylaldehyde derivatives.