Synthesis Of Pyrans And Chiral Amines Via Nucleophilic Addition Reaction Of Alkylidenecyclopropanes

Pyrans and chiral amines are important chemical skeletons in organic chemistry,which are found in many natural products and medical drugs.At the same time,pyran and chiral amine derivatives have high biological activity and are widely used in many fields such as chemistry,pharmacy and medicine.Therefore,it is very important to develop new and efficient catalytic systems to prepare pyrans and chiral amines.Alkylenecyclopropanes(ACPs)are a kind of small ring compounds with high reactivity and stability at room temperature.These compounds have high ring tension and are prone to various reactions such as addition,ring opening and rearrangement.In different catalytic systems,ACPs react with different substrates,which provide a simpler and more efficient synthetic route for some compounds with complex structures.Therefore,in this thesis,pyrans and chiral amines were synthesized by nucleophilic addition reaction of ACPs catalyzed by transition metals.The thesis is divided into three parts:In the first part,the biological activities of dihydropyrans and chiral amines are briefly introduced,and the research progress of transition metal-catalyzed ACPs addition reaction in recent ten years is reviewed,mainly from two different ring-opening modes.The second part is the selective 1,4-addition and cycloaddition reactions regulated by palladium-catalyzed ligands.A series of γ-dienyl-α-ketoesters and 2H-pyran derivatives can be selectively prepared in moderate to excellent yields by using ACPs and β,γ-unsaturatedα-ketoesters as starting materials,and the reaction has good regioselectivity.The third part is the enantioselective addition reaction catalyzed by palladium and Bronsted acid.In this reaction,ACPs and imine were used as starting materials.By screening chiral ligands and Bronsted acid,various chiral dienamines were obtained with a yield as high as 96% and an ee value of 98%.