Nickel-Catalyzed Desymmetric Hydrogenation of Cyclohexadienones: An Efficient Approach to All-Carbon Quaternary Stereocenters

Nickel-catalyzed desymmetric hydrogenation has been achieved. With the Ni(OTf)(2)/(S,S)-Ph-BPE system, a series of gamma,gamma-disubstituted cyclohexadienones were transformed to the corresponding cyclohexenones with a chiral all-carbon quaternary center at the gamma position in high yields (92-98%) and excellent enantioselectivities (92%-99% ee). This catalytic system can also tolerate the desymmetric reaction of spirocarbocyclic cyclohexadienones to produce the corresponding cyclohexenones bearing a chiral spiro quaternary carbon with high yields (94%-98%) and ee values (96%-99% ee). Furthermore, this methodology provides an efficient and concise synthetic route to the intermediate of natural products cannabispirenones A and B.