Nickel-Catalyzed Asymmetric[3+2] Annulation Of Cyclopropenones And ?,?-Unsaturated Compounds

Transition-metal catalyzed carbon-carbon bond cleavage reaction has attracted great attention in recent years.This process has not only emerged as a useful strategy for synthesis of complex molecular skeletons,but also satisfied atom economy.However,transition-metal catalyzed asymmetric carbon-carbon bond activation reaction was relatively lagging behind.This thesis mainly focused on nickel-catalyzed enantioselective [3+2] annulation of cyclopropenones and ?,?-unsaturated Ketones/Imines through C-C bond activation.This atom-economic reaction is both highly chemo-and enantioselective(88–99% ee),with the C=O or C=N bond exclusively participating in the cycloaddition,affording ?-alkenyl butenolides or ?-lactams,respectively,bearing a tetra-substituted carbon.The influence of reaction parameters,including the structure of chiral ligands,temperature and solvent on the reaction was investigated.This coupling system was efficient with broad substrate scopes.Derivatization revealed that the coupling system turned out to be synthetically useful.On the basis of our studies and DFT studies,a plausible reaction mechanism was given.