Research On The Palladium-and Rhodium-Catalyzed Selective

C-C bonds are present in the skeleton of almost all organic molecules. Thus, the development of new reactions for construction of C-C bonds is a hot research area for organic chemists all the time. In the past several decades, the transition-metal catalyzed C-C bond formation reaction has become the most efficient strategy for construction of C-C bond because of good functional group tolerance, high selectivity, high conversion, mild conditions etc. In this doctoral thesis, palladium-catalyzed three-component coupling reaction of benzyl halides, allyltributylstannane, and activated olefins is described; the rhodium-catalyzed oxidative annulation of N-arylamides with internal alkynes is also described.In the first part, the three-component coupling reactions of benzyl halides, allyltributylstannane, and activated olefins were achieved by using palladium nanoparticle catalyst generated in situ. Under the optimized conditions, the three-component coupling reactions proceed smoothly, and the corresponding benzylallylation products were obtained in70%-87%yields. This protocol shows good functional group tolerance, such as halide (F, Cl, Br), methyl, methoxyl, and nitro groups. TEM (Transmission electron microscopy) analysis of the reaction mixture reveals that the palladium nanoparticles were generated in situ, which was considered as the active species. This methodology provides a new route for bis-functinalization of activated olefins under mild conditions.In the second part, regioselective control by a catalyst switch in palladium-catalyzed benzylallylation of activated olefins (α-benzyl-β-allylation versus α-allyl-β-benzylation) is described. The three-component coupling reactions of2-(bromomethyl)naphthalenes, activated olefins, and allyltributylstannane proceed smoothly in the presence of palladium nanoparticle catalyst to provide α-benzyl-β-allylation products in65%-86%yields. The regioselectivity of the benzylallylation reaction was completely overturned with Pd(PPh3)4as the catalyst to give α-allyl-β-benzylation products in13%-87%yields. These reactions show good functional group tolerance, such as halide (F, Cl, Br), methyl, and methoxyl groups.In the last part, rhodium-catalyzed oxidative annulation of N-arylamides with two equivalents of internal alkynes is developed. Highly-substituted naphthalenes were obtained in24%-88%yields by this method. The reaction showed good regioselectivity and afforded sole regioisomer when unsymmetrical alkynes were used. This protocol shows broad substrate scope and good functional group tolerance. On the other hand, this strategy also provides opportunities for further application of N-arylamides in organic synthesis due to their easy deprotection and modification.