Palladium-catalyzed intramolecular reductive cross-coupling of Csp2-Csp3 bond formation.

A Pd-catalyzed efficient reductive cross-coupling reaction without metallic reductant to construct a Csp(2) -Csp(3) bond has been reported. A Pd(IV) complex was proposed to be a key intermediate, which subsequently went through double oxidative addition and double reductive elimination to produce the cross-coupling products by involving Pd(0/II/IV) in one transformation. The oxidative addition from Pd(II) to Pd(IV) was partially demonstrated to be a radical process by self-oxidation of substrate without additional oxidants. Furthermore, the solvent was proved to be the reductant for this transformation through XPS analysis.