| The transition-metal-and organic-molecular-catalyzed coupling reactions are versatile methods for the generation of new carbon-carbon and carbon-heteratom bonds in organic synthesis,and it has become a hot topic in current organic chemistry.Transition-metal salts and their complexes and organic moleculars have been used as catalyst directly in the classic methods.However,the toxicity,high cost of the transition metals and chiral organic moleculars,and the metal contamination of the products remained to be considered.In order to overcome these drawbacks,devetoping green synthetic methods and efficient,reusable catalytic systems have become an important research field for organic chemists.In this dissertation,a few SiO2@Fe3O4-or polymer-supported catalysts have been prepared,and good results have been achieved when they were used as the catalysts for carbon-carbon and carbon-heteratom bond-formation reactions.-The main works are summarized as follows:1.A highly efficient,air-and moisture-stable and easily recoverable magnetic nanoparticle-supported palladium catalyst has been developed for the Suzuki,Sonogashira and Heck reactions.A wide range of substrates could be employed successfully under aerobic conditions.In particular,the performance of the magnetic separation of the catalyst was very efficient,and it was possible to be recovered and reused at least eight times without significant loss of its catalytic activity.2.A highly efficient visible-light-mediated C-C and C-P coupling reactions of sp3 C-H bonds adjacent to the nitrogen atom in tetrahydroisoquinoline derivatives with pronucleophiles such as nitroalkanes,malononitrile,dimethyl malonate and H-phosphonate diesters were achieved by using a magrnetic nanoparticle-supported eosin Y bis-benzyltriethylammonium salt(MNPs-Eosin Y)as the catalyst and air as the sole oxidant,affording the corresponding products in good to excellent yields under mild reaction conditions.Notably,the supported eosin Y catalyst could easily be separated from the reaction mixture by an external permanent magnet and could be recycled at least eight times without a significant loss of activity.3.A visible-light-induced decarboxylative sulfonylation of cinnamic acids with sodium sulfinates for the synthesis of vinyl sulfones were developed.The reaction underwent smoothly in the presence of magnetic nanoparticle-or Merrifield resin-supported Rose Bengal ammonium salt as a photocatalyst,tert-butyl hydroperoxide(70%in water)as an oxidant in aqueous DMSO solution at room temperature under green LED(530-535 nm)irradiation in air atmosphere,generating the desired products in good yields.Notably,the supported catalyst could easily be separated from the reaction mixture by an external permanent magnet or filtration and could be recycled at least six times without a significant loss of activity. |
