Asymmetric Total Synthesis Of Gymnothelignan L And Total Synthetic Studies Toward Lycopodium Alkaloids Lycoplanine A And Lycopladine H

This dissertation is mainly focused on asymmetric total synthetic of gymnothelignan L and total synthetic studies toward lycoplanine A and lycopladine H.It consists of the following three chapters: Chapter 1.Construction of Axially Chiral Compounds via Asymmetric Methods(review)Axially chiral compounds have received much attention from chemists because of their widespread appearance in natural products,biologically active compounds,and useful chiral ligands in asymmetric catalysis.This review describes certain advances in the catalytic asymmetric synthesis of axially chiral compounds involving the following strategies: kinetic resolution,desymmetrization,cyclization,addition,aryl-aryl coupling,and so on.Chapter 2.Studies on Asymmetric Total Syntheses of Gymnothelignan L and Gymnothelignan MThis chapter introduction of background for the isolation,novel structures and biogenetic hypothesis of gymnothelignan A-O was provided.At last,the first asymmetric total synthesis of gymnothelignan L has been accomplished in 14 steps with 11.2% overall yield.The synthetic approach features an anti Evans aldol reaction,a diastereoselective methylation,a Suzuki–Miyaura coupling and a bioinspired desymmetric transannular Friedel–Crafts reaction.Notably,the synthesis further demonstrated the biogenetic pathway that dibenzocyclooctene-type lignans are generated from eupomatilone-type lignans.Chapter 3.Studties on the Total Syntheses of Lycopodium Alkaloids Lycoplanine A and Lycopladine HThis chapter introduces isolation,structures,biological transformation relationships and synthetic development of lycopladine H.Several approaches have been tried towards the total synthesis lycoplanine A and key intermediate has been prepared.This work is on going.