One-pot synthesis of quaternary carbon centered cyclobutanes via Pd(II)-catalyzed cascade C(sp3)–H activations

A novel approach toward quaternary carbon centered cyclobutanes through Pd(II)-catalyzed sequential intramolecular methylene C–H alkylation and intermolecular methine C–H bond arylation, alkenylation, alkylation, alkynylation, allylation, benzylation or alkoxylation is described. These quaternary carbon centered cyclobutanes could be further diversified through Pd(II)-catalyzed γ-C(sp3)–H bond activations. The synthetic utility of this novel approach was exemplified by its application to the synthesis of a bioactive small molecule.