Asymmetric Catalysis Reactions Combining Of Transition Metal And Chiral Phosphoric Acid

Transition metal catalysis combined with organocatalysis has been shown to be an efficient asymmetric synthetic methodology. Various limitations of the traditional single catalyst system for asymmetric catalytic reactions were completely broken through by this robust catalytic method. A wide range of structurally diverse optically active products could be directly synthesized by employing simple and available substrates under the catalysis of transition metal/organocatalyst dual catalyst system in only one step. Chiral Br(?)nsted acids, especially chiral phosphoric acids derived from BINOL, have been demonstrated to be privileged catalysts enabling a diverse range of enantioselective transformations. More recently, the combination of Bronsted acids and transition metal complexes has emerged as a powerful tool in organic chemistry today.An asymmetric relay catalytic multicomponent reaction by using gold(Ⅰ) complex/chiral phosphoric acid was disclosed, which is able to assemble the readily available and easily accessible substrates into enantioenriched aromatic spiroacetals. The method provided an important alternative of known methods to directly access highly enantioenriched spiroacetals and would be potentially applied to the synthesis of spiroacetal motifs presented in natural products.Moreover, we have demonstrated a combination of the relay and cooperative catalysis with palladium/gold/phosphoric acid ternary system providing an unprecedented entry to pyrrolidine derivatives in high yields. In this cascade reaction, the gold complex serves a catalyst responsible for the hydroamination while palladium and Br(?)nsted acid cooperatively catalyze the allylic alkylation.Additionally, during the investigation of Pd(Ⅱ)/chiral phosphoric acid dual catalysts system, an asymmetric organocatalytic direct C-H/C-H oxidative coupling reaction of N1,N3-diphenylmalonamides was well established by using chiral organoiodine compounds as catalysts, wherein four C-H bonds were stereoselectively functionalized to give structurally diverse spirooxindoles with high levels of enantioselectivity.