Metal-Ligand Bifunctional Iridium-catalyzed Hydrogen Transfer Reaction

With the development of green chemistry,exploring highly-atomic economy reactions has become a hot topic in synthetic chemistry.Developing new catalysts to increase the atomic economy of the reaction is a important method.For the high activity of transition metal iridium catalysts,the metal-ligand bifunctional iridium catalysts were used to select low-toxicity raw materials,reduce or avoid the formation of by-products,and explore more moderate reaction conditions in the thesis.The major works were listed below.The a-alkyl ketones were synthesized by dehydrogenation/a-alkylation reactions of secondary and primary alcohols in the presence of the metal-ligand bifunctional catalyst[Cp*Ir(2,2'-bpyO)(H2O)].In the reaction,low-toxic alcohols were used as the materials,and a catalytic amount of weak base Cs2CO3 was used.The method can effectively avoid the formation of ?-alkylation products of secondary alcohols,which was a method with mild reaction conditions and high atomic economy.The quinolines were synthesized from o-aminobenzyl alcohols and ketones in the presence of the water-soluble metal-ligand bifunctional catalyst[Cp*Ir(6,6'-(OH)2-2,2'-bpy)(H2O)][OTf]2.In the method,water was chosen as solvent and quinolines were synthesized by acceptorless dehydrogenation prosess.So,the method met the requirements of green chemistry and atomic economy.The 1,2,3,4-tetrahydroquinolines were synthesized by the cyclization/hydrogenation reactions of o-aminobenzyl alcohols and ketones in the presence of the metal-ligand bifunctional catalyst[Cp*Ir(2,2'-bpyO)(H2O)].The use of simple raw materials can avoid the limitations of hydrogenation reactions of quinolines.In addition,HCOOH/Et3N was used as the hydrogen source in the hydrogenation reaction.It was a safer and milder reaction condition,which met the requirements of green chemistry.Under neutral conditions,primary alcohols can be synthesized by the transfer hydrogenation of aldehydes in the presence of the metal-ligand bifunctional catalyst[Cp*Ir(2,2'-bpyO)(H2O)].And this method was also suitable for the transfer hydrogenation reactions of unsaturated aldehydes and ketones.The less toxic,less expensive and commercialized isopropanol was selected as the solvent and hydrogen source.This was a mild method that met the requirements of green chemistry.