Enantioselective Nickel-Catalyzed Reductive Aryl/Alkenyl–Cyano Cyclization Coupling to All-Carbon Quaternary Stereocenters

An enantioselective nickel-catalyzed intramolecular reductive cross-coupling of C(sp2) electrophiles and cyano groups is reported. Enantioenriched CN-containing all-carbon quaternary stereocenters are assembled by desymmetrizing cyclization of aryl/alkenyl halide-tethered malononitriles. The use of an organic reductant, (EtO)2MeSiH, is crucial to the enantioselectivity and reactivity. Applications of the method are demonstrated through the synthesis of bioactive molecules and their cyanated analogues and the total synthesis of the natural product diomuscinone. This study exhibits the potential of desymmetrizing reductive coupling strategies to access structurally rigid and synthetically versatile molecules from readily available starting materials.