The discovery of novel reactivities with carbon–carbon double bonds (C=C) is not only useful for chemical synthesis and theoretical studies, but is also important for applications in biology, because C=C bonds are abundant in nature. As we all know, C=C bonds are fundamental structures of alkenes, where the C=C π bond is localized above and below the C–C σ bond wherein π electrons are relatively far away from the nuclei and are loosely bound, so that they can be easily attacked to construct a new bond.1,2 Indeed, addition reactions are one of the common reactions of C=C bonds, such as reactions with HX (X = Cl, Br, I, OH, SH, RS, etc.) as described in Scheme 1a.3 Additionally, C=C bonds can also be cleaved by oxidation as in the typical ozonolysis of alkenes (Scheme 1b).4 However, because of their unique structure, reductive cleavage of alkenes (Csp2–Csp2) has rarely been reported so far.