Study On Mukaiyama-Mannich Addition Of α-diazo Silyl Enol Ether Catalyzed By Mg(Ⅱ)

This thesis mainly focused on investigating Mukaiyama-Mannich addition reaction ofα-diazo silyl enol ethers with imine or nitrone catalyzed by Lewis acidic Mg（Ⅱ）,which is divided into the following three parts.The first chapter reviews the Mukaiyama-Mannich reaction of imine or nitrones catalyzed by different catalysts as well as its application in the synthesis of heterocyclic compounds.Results and mechanistic discussions on the systematic studies of Mukaiyama-Mannich reaction ofα-diazo silyl enol ethers with various imine substrates catalyzed by MgI₂·（OEt₂）n are documented in chapter 2.The effects of solvents and various catalysts on the reaction yield were investigated in detail,and the optimum reaction conditions were determined.The results demonstrated that MgI₂·（OEt₂）n showed good catalytic effeciancy on various aromatic imines,heteroaromatic imines and unsaturated imines.However,ketoimines derived from aliphatic ketones or aromatic ketones are unreactive towardα-diazo silyl enol ethers.Furthermore,we have revealed in this chapter the unique catalytic reactivity of MgI₂·（OEt₂）n in the chemoselective Mukaiyama-Mannich coupling of aromatic aldehyde and its parent imine withα-diazo silyl enol ethers.The crossover experiments showed that imines are more reactive than the parent aldehydes.One-pot Mukaiyama-Mannich reaction of aldehydes,amines withα-diazo silyl enol ethers catalyzed by MgI₂·（OEt₂）n was developed.This magnesium-catalyzed reaction featured mild conditions,simple operation,good regional selectivity and high yield.The third chapter discussed Mukaiyama-Mannich reaction ofα-diazo silyl enol ethers with nitrones catalyzed by MgI₂·（OEt₂）n.The results suggested that aromatic nitrones,unsaturated nitrones,aliphatic nitrones and heteroaromatic nitrones are reactive substrates towardα-diazo silyl enol ethers..Meanwhile,the catalytic reactivity of magnesium halides was evaluated,respectively.This catalytic reaction mechanism was proposed in this chapter.We have provided a novelmethod for the synthesis of oxazine derivatives and pyrrole derivatives.