Palladium-Catalyzed C-C Bond Activation/Suzuki Reaction Of Methylenecyclobutanes

Main observation and conclusionTransition-metal catalyzed C-C bond activation is a formidable challenge owing to the high bond energy. We report here a novel palladium-catalyzed C-C bond activation manner of methylenecyclobutanes followed by subsequent Suzuki cross-coupling reaction affording multisubstituted indanes. The tandem reaction process involves intramolecular carbopalladation of double bond, beta-carbon elimination and intermolecular trapping of the transient sigma-alkylpalladium complex with boronic acids. A new TADDOL-derived phosphoramidite ligand bearing fluorine and silicon-based bulky groups is found to be efficient for C-C bond activation of methylenecyclobutanes.