Activation Of Asymmetric C-H Bonds Catalyzed By Transition Metals Palladium And Ruthenium

Transition-metal-catalyzed asymmetric C-H activation is a direct and efficient pathway for the construction of complex compounds,and its application in drug synthesis was widely explored by chemists.However,directed and efficient catalytic activation of C-H bonds is a long-standing challenge,because C-H bonds are ubiquitous in organic molecules.In this dissertation,we firstly investigated the palladium-catalyzed and chiral-amide-controlled asymmetric C-H bond activation/cyclization to construct chiral compounds.Next.the synthesis and application of semi-sandwich Ru complexes was also studied.1.Palladium-catalyzed intramolecular C-H acti vati on/cyclization of o-bromotriarylphosphine oxides were successfully achieved by using chiral amide ligands with different substituents to control enantioselectivity.Under standard conditions,substrates with different substituents gave the corresponding cyclized products in up to 99%yield and ee value.2.A palladium-catalyzed asymmetric C-H bond functionalization reaction was developed here for the efficient construction of planar chiral ferrocene compounds.After intense screening.cyclohexyloxy substituted chiral amide was found the appropriate ligand for enantioselectivity control in the cyclization of o-bromobenzoyl ferrocenes.Up to 93%yield and 93%enantioselectivity could be obtained when the solvent switched to tert-butanol.With optimized conditions,a series of planar chiral ferrocene derivatives were synthesized.3.Novel semi-sandwiched Ruthenium complexes were synthesized by using different substituted cyclopentadienyl analogs.As initial attempt,these Ruthenium complexes were tested in remote C-H activation reaction of pyridylphosphoramides,allyl substitution reaction,propargyl substitution reaction,and cyclization of silyl ethers.