The Research Of Palladium Or Iron Catalyzed Synthesis Of Ketoesters And Aromatic Ketones

Ketoesters and aromatic ketones are compounds with high value,and are widely present in biologically active molecules such as pharmaceuticals,pesticides,and natural products.However,in the traditional synthesis methods of ketoesters and aromatic ketones,the reaction conditions have some drawbacks,such as harsh reaction,multi-step reaction,consumption of a large amount of Lewis acid,and the consumption of stoichiometric metal reagents,and production of a large number of by-products.Therefore,it is of great significance to develop a simple and environmentally friendly one-step synthesis method of ketoesters and aromatic ketone derivatives.Based on the above background,our research includes palladium-catalyzed direct?-ketoesterification of 8-methylquinoline derivatives with?-ketoacids via dehydrogenation coupling reaction and iron-catalyzed dual cleavage reaction of keto acid and aliphatic aldehyde to the synthesis of aromatic ketone/ketone ester.The details are as follows.?1?Study on the synthesis of ketoate derivatives.This method uses8-methylquinoline derivative and?-keto acid derivative as substrate,Pd₂?dba?₃ as catalyst,Ph I?OAc?₂ as oxidant,and CHCl₃ as solvent achieve the direct oxidation reaction of 8-methylquinoline at the benzyl position,and the?-ketoesters is prepared with high efficiency.This reaction is conducted at a mild temperature,regiospecific,compatible with air,and can be expanded to the gram scale.?2?Study on the iron-catalyzed synthesis of aromatic ketones/ketoesters.This method uses?-keto acid derivatives and aliphatic aldehyde as substrates,Fe?acac?₃ as catalyst,DTBP and K₂S₂O₈as oxidants,and Et OAc as solvents to achieve radical cross-coupling reactions between keto acids and aliphatic aldehydes,and aromatic ketones/ketoesters were prepared with high efficiency.Compared with these conventional methods,our strategy do not need to consume large amounts of Lewis acid,do not need to require pre-synthesis of stoichiometric metal reagents,the influence to the environment has been greatly reduced.In addition,when tertiary aldehydes were used as carbonyl sources,ketone esters were selectively achieved instead of ketones.