Catalytic Synthesis And Application Of Chiral Diarylmethylamines And Gem-difluoroalkene Derivatives

C-X(C-N,C-F,etc.)bond is widely existed in some drug molecules and natural products.Therefore,it is of great significance to efficiently construct C-X bond containing molecules,especially those with C-X bond at stereogenic centers.In recent years,great progress has been made in the synthesis of chiral carbon-hetero bond containing molecules via transition metal-catalyzed methods.In this thesis,a new method for the synthesis of chiral diaryl methylamines(containing C-N bond molecules)catalyzed by a transition metal complex has been developed;In addition,a method of silylation of trifluoromethyl substituted olefins for the preparation of gem-difluoroalkenes(containing C-F and C-Si bonds)has also been explored.The main contents are as follows:1.An enantioselective synthesis of chiral diarylmethylamines by asymmetric addition of arylboric acids to N-protected aldimines catalyzed by a transition metal complex is described.The use of a chiral palladacycle complex as a catalyst enables the asymmetric addition of aryl boric acids to imines to proceed smoothly providing the optical activitive diaryl methylamines.The method has the advantages of wide range of reaction substrates,mild reaction conditions,high yields and high enantioselectivity.Furthermore,a catalytic cycle and a stereochemical pathway were proposed and discussed.2.Silylation of trifluoromethyl substituted olefins has also been explored for the preparation of gem-difluoroalkenes(containing C-F and C-Si bonds).The method employs trifluoromethyl substituted alkenes as acceptors and Ph Me2 Si Bpin as a silylating reagent in the presence of copper catalyst.The reaction is assumed to proceed via an addition/?-F elimination process.The catalysts were screened and reaction conditions including base,solvent,reaction temperature and time were optimized.Under the best conditions,high yields(99%)of the product was obtained with a copper catalyst.