Study On The Formation Of C-N And C-O Induced By Lanthanide Lewis-acid

Lewis-acid (LA)-catalyzed reactions are of great interest because of their unique reactivities and selectivities and mild reaction conditions used. This thesis mainly focused on the formation of C-N and C-O induced by lanthanide Lewis acid. The main results obtained are as follows:1. Guanylating of Amines with carbodiimide Catalyzed by some different Lewis acids.In the second chapter guanylation of amine with carbodiimide catalyzed by Ln(OTf)3were studied. Lanthanide triflates are the efficient catalysts for the reaction. The catalytic activity depends on the lanthanide metals and follows the trend:La<Nd<Sm<Eu<Er<Yb. The guanylation of aromatic amine with carbodiimide carried out with0.5mol%Yb(OTf)3as catalyst at room temperature in the absence of solvent gave the corresponding products in high yields. It is compatible with a wide range of substituents at the phenyl ring, regardless of the electron-withdrawing or electron-donating groups. The guanylation of aliphatic amine with carbodiimide catalyzed by2.0mol%Yb(OTf)3at60℃temperature in the absence of solvent gave the target products in the yield of76%-94%. A possible mechanism is proposed.In the third chapter SmI2serve as the precatalyst for guanylation of aromatic amine with carbodiimide is described. The reaction can’t be taken smoothly when the solvent can coordinate with SmI2, Toluene is good for the reaction. When the guanylation catalyzed by3.0mol%SmI2in toluene at60℃, the yield of products was86%-97%. Compared to known lanthanide catalysts, samarium diiodide is cheap and easily prepared.In the sixth chapter it was found that the trend of some Lewis acids catalytic activity is ZnCl2<YbCl3≈FeCl3<SnCl2<AlC13.0.5mol%AlCl3can catalyze the guanylation of aromatic amine with carbodiimide efficiently at room temperature in the absence of solvent. The guanylation of aliphatic amine with carbodiimide catalyzed by 2.0mol%AlCl3at60℃temperature under solvent free condition gave the products in good to excellent yields. In situ IR spectroscopy gave some evidence of the proposed mechanism.2. In the fourth chapter intramolecular hydroalkoxylation of unactivated olefins catalyzed by [Ln(CH3CN)9]3+[(AlCl4)3]3-·CH3CN was studied. Trend of the intramolecular hydroalkoxylation of2-allylphenol is Nd≈Pr<La<Sm≈Gd<Y<Yb.2-allylphenol could be completely transformed to2,3-dihydro-2-methylbenzofuran, when [Yb(CH3CN)9]3+[(AlCl4)3]3-·CH3CN was catalyst at65℃temperature in CHC13after24hours. Trend of the intramolecular hydroalkoxylation of aliphatic enol is Yb≈Gd<Y≈Er<La<Pr≈Nd≈Sm. Intramolecular hydroalkoxylation of aliphatic enol catalyzed by2.5mol%[Nd(CH3CN)9]3+[(AlCl4)3]3-·CH3CN at85℃temperature in DCE after24hours, the yield of products was86%-97%.[AlCl(CH3CN)5]2+[(AlCl4)2]2-·H3CN and [Nd(CH3CN)9]3+[(FeCl4)3]3-were synthesized, the structures were determined by X-ray single crystal diffraction. The catalytic activity of [AlCl(CH3CN)5]2+[(AlCl4)2]2-·H3CN or [Nd(CH3CN)9]3+[(FeCl4)3]3-is lower than the catalytic activity of [Ln(CH3CN)9]3+[(AlCl4)3]3-·CH3CN.3. In the firth chapter2,3-dihydroquinazolin-4(1H)-ones and3,4-Dihydro-(2H)-1,2,4-benzothiadiazine-1,1-dioxides were separately synthesized by the reaction of aldehyde with2-aminobenzamide and the reaction of aldehyde with2-aminobenzensulfonamide catalyzed by [Ln(CH3CN)9]3+[(AlCl4)3]3-·CH3CN. When the reaction catalyzed by0.5mol%[Yb(CH3CN)9]3+[(AlCl4)3]3-·CH3CN at room temperature in CH3CN, the yield of2,3-dihydroquinazolin-4(1H)-ones was83%-96%and the yield of3,4-Dihydro-(2H)-1,2,4-benzothiadiazine-1,1-dioxides was88%-95%.