Transition Metal-Catalyzed Selective Carbon-Hydrogen Bond Activations And [3+2]Cyclization Reaction

In this thesis,simple and efficient synthetic routes to planar chiral ferrocene derivatives and ferrocenyl heterocycles are mainly studied.Moreover,the amidation of acetophenone hydrazones are also explored.The detailed results are as follows:1.Palladium(II)-catalyzed enantioselective C-H alkenylation of ferrocenecarboxylic acidPlanar chiral ferrocene derivatives are widely used in asymmetric catalysis,biomedicine,functional materials and other fields.Simple and effective palladium-catalyzed ferrocenecarboxylic acid enantioselective C-H alkenylation has been developed,using chiral amino acids as ligands.Ferrocene derivatives with planar chirality were obtained with moderate to good yields and good enantioselectivity.This reaction system features:1)no additional metal oxidant,using oxygen as a green oxidant;2)tolerance of broad substrates;3)cheap and easily avaiable chiral amino acids as ligands;4)the mild reaction conditions.Ferrocene was oxidized into ferrocenium by molecular oxygen,which works as terminal oxidant to regenerate palladium(II)from palladium(0)for the next catalytic cycle(Scheme 1).(?)2.Synthesis of 2,4,5-trisubstituted oxazoles via Co-catalyzed[3+2]cyclization of ferrocenyl enamine with dioxazolonesA simple and efficient cobalt-catalyzed[3+2]cyclization reaction was developed to construct ferrocenly oxazoles starting from ferrocenyl enamine and dioxazolones.This reaction tolerates a wide range of substrates,not only suitable for 3-aryl dioxazolidinones,but also has good applicability to 3-vinyl dioxazolidinones and 3-alkyl dioxazolidinones(Scheme 2).In addition,a series of novel 4-ferroceneformyl-polysubstituted oxazolones were synthesized.(?)3.Cobalt-catalyzed ortho-amidation of diaryl hydrazones with dioxazolonesThe diaryl hydrazones has a sub-structure”-C=N-N=C-”and widely present in various agricultural chemicals,medicines and materials.Herein,Cobalt-catalyzed orrho-amidation of acetophenone hydrazones with dioxazolones has been developed under air conditions(Scheme 3).In addition,the ortho-amidated acetophenones can be easily converted into pharmacologically active 2-aryl-4-quinolones.(?)...