Synthetic Application Research On Intramolecular Cycloaddition Of DA-Cyclopropane With ?-Diazo Ketone

In this thesis,the intramolecular cycloaddition reaction of DA-cyclopropane with ?-diazo ketone was used as a key reaction in the synthesis of key intermediates in formal synthesis of(±)-platensimycin and polygalolide B(DA-cyclopropane refers to cyclopropane containing a push-pull electron system).Under the catalysis of Lewis acid,intramolecular cycloaddition of DA-cyclopropane and ?-diazo ketone constructed the derivatives of a bridged ring and a lactone ring skeleton.Some complex natural products contain such a core skeleton,so the method applied to synthesis is very meaningful.This thesis is divided into two chapters:The first chapter mainly reviewed the various cycloaddition reactions of cyclopropane,The cyclization,insertion as well as other reactions of diazo compounds.The [3 + 2] cycloaddition reaction of DA-cyclopropane with unsaturated bond-containing compounds was described.Rearrangement reaction,cyclization reaction,X-H bond insertion and formation of various ylides of diazo compounds were also introduced.In the second chapter,the important intermediates in the synthesis of(±)-Platensimycin and Polygalolide B were prepared by cycloaddition of DA-cyclopropane with ?-diazo ketone.First,the synthetic background of these two natural products was introduced,followed by a elaboration of the reverse synthesis analysis of formal synthesis of(±)-platensimycin.Based on the previous research foundation.The preparation of important intermediates and its synthesis conditions in the formal synthesis of(±)-platensimycin were studied in detail.Finally,the reverse synthesis analysis of formal synthesis of Polygalolide B was introduced,the preparation of important intermediates was also tried.In this paper,the Lewis acid-catalyzed intramolecular cycloaddition of DA-cyclopropane with ?-diazo ketone was applied to prepare the important intermediates in the foamal synthesis of(±)-platensimycin and polygalolide B,which had reference significance on synthesis of natural products with complex bridged rings.