Cross-dehydrogenative coupling involving benzylic and allylic C–H bonds

In recent years, the cross-dehydrogenative coupling (CDC) has demonstrated to be a powerful synthetic tool to form C–C bonds from two C–H bonds. This high atom-economic transformation is an attractive alternative to the classical substitution and coupling approaches for the benzylation and allylation of carbon centers, which rely on the reaction of adequately functionalized starting materials. This review emphasizes the utility of the CDC through the coupling of benzylic and allylic C–H bonds with C(sp)–H, C(sp2)–H and C(sp3)–H bonds.This work was generously supported by the Spanish Ministerio de Ciencia, Innovación y Universidades (MICIU; grant no. CTQ2017-88171-P), the Generalitat Valenciana (GV; grant no. AICO/2017/007) and the Universidad de Alicante (grant no. VIGROB-285/19). I. B. is also grateful to the Spanish MICIU for a Juan de la Cierva-incorporación grant (no. IJCI-2017-33706)