Studies On The Total Syntheses Of Tazettine,6a-epipretazettine,Lycojaponicumin D,Alopecuridine,12-deoxyhuperzine O And Lycopodine

This dissertation is mainly focused on total syntheses of Amaryllidaceae Alkaloids Tazettine and 6a-Epipretazettine,and Lycopodium alkaloids Lycojaponicumin D,Alopecuridine,12-Deoxyhuperzine O and Lycopodine.It consists of the following four chapters:Chapter 1 Synthetic Developments of Lycopodine-type Lycopodium Alkaloids(review)This review introduces the biosynthetic pathway and classification of Lycopodium alkaloids,and emphatically summarizes the total synthesis of Lycopodine-type Lycopodium alkaloids that are elaborated from early synthesis,synthetic strategies based on Stork's intermediates,synthetic strategies based on Heathcock's intermediates,strategies of Mannich cyclization and other synthetic strategies,respectively.Chapter 2 Formal Syntheses of the Amaryllidaceae Alkaloids(±)-Tazettine and (±)-6a-EpipretazettineThis chapter introduces isolation,structures,biological properties and synthetic developments of Amaryllidaceae alkaloids Tazettine and 6a-Epipretazettine.An efficient synthesis of(±)-(6a?)-5-demethyl-6a-deoxy-5-(methoxycarbonyl)tazettinone,the common core structure of Amaryllidaceae alkaloids(±)-Tazettine and(±)-6a-Epipretazettine,has been accomplished in 6 steps with 54%overall yield on a gram scale,starting from commercially available p-hydroxybenzaldehyde and piperonyl alcohol.And so the formal syntheses of Tazettine and 6a-Epipretazettine were completed.The requisite pentacyclic skeleton is constructed by a tandem intramolecular oxidative Friedel-Crafts/aza-Michael reaction as the key step,which builds up two chiral centers and two rings in one step.Chapter 3 Studties on the Total Syntheses of Lycopodium Alkaloids Lycojaponicumin D and AlopecuridineThis chapter introduces isolation,structures,biological properties,biological transformation relationships and synthetic developments of Lycopodium alkaloids Alopecuridine,Sieboldine A,Lycojaponicumins D and Lycojapodine A.And three key intermdiates including a-hydroxy-?,?-enone and two vicinal diols have been prepared using Rubottom Oxidation,Ring-Closing Metathesis,Dihydroxylation and Oxidation of Diol,staring from commercially available(R)-(+)-pulegone,3-aminopropanol and allylacetic acid,through the three synthetic route respectively.But Deprotection and following Mannich Cyclization of a-hydroxy-?,?-enone and Oxidation of two vicinal diols can't work smoothly in many conditions.To solve the problem,a new strategy has been proposed towards the triketone.The syntheses of Lycojaponicumin D and Alopecuridine are currently in progress.in our group.Chapter 4 Studties on the Total Syntheses of Lycopodium Alkaloids 12-Deoxyhuperzine O and LycopodineThis chapter introduces isolation,structures,biological properties,biological transformation relationships and synthetic developments of Lycopodium alkaloids 12-Deoxyhuperzine O and Lycopodine.And the key ketol has been prepared via a few simple reactions and the following Sakurai-type Michael Addition,staring from commercially available(R)-(+)-pulegone,3-aminopropanol and 1,3-propanediol.Preliminary unsuccessful explorations of the key Aza-Prins Cyclization have laid the foundation for the syntheses of 12-Deoxyhuperzine O and Lycopodine which are underway at present.