Merging Aldehydic C–H Activation with Strain Release C–C Bond Cleavage of Bicyclo[1.1.0]butanes under Rh(III) Catalysis

Herein, we report a Rh(III)-catalyzed aldehydic C-H activation followed by strain release C-C cleavage of bicyclobutanes (BCBs) to access α-methylene-1,5-dicarbonyl motifs under mild conditions with excellent yields employing equimolar amounts of both reactants. This protocol is highly chemoselective and accommodates a wide variety of substrates. Synthetic utility of the developed protocol was demonstrated by carrying out gram scale synthesis and further functionalization of the final products. Additionally, α-methylene-1,5-dicarbonyl motifs obtained from amide BCBs undergo alkenyl C-H annulation with alkynes to afford substituted α-pyrones.