Total Syntheses Of Mupirocin H And The Lycopodium Alkaloids Palhinine A And Studies On Enyne Cyclization Of All-carbon Enynyl Esters

The thesis is mainly focused on studies of the enyne cyclization of all-carbon enynyl esters and total syntheses of mupirocin H and palhinine type Lycopodium alkaloids. It consists of the following four parts:Chapter 1. Synthetic Highlights and Recent Developments of Fawcettimine Type Lycopodium Alkaloids, (review)Since their discovery, the Lycopodium alkaloids have been of great interest to the scientific community as compounds that are both structurally interesting and biologically active. As an important class of Lycopodium alkaloids, the Fawcettimine-type Lycopodium alkaloids have garnered significant attention from synthetic organic chemists. This chapter will focuses on synthetic highlights and recent developments of Fawcettimine type Lycopodium alkaloidsChapter 2. Enyne Cyclization/1,2 Ester Migration Reaction of 1,6- all-carbon enynyl esters Controlled by Substituent Effects.A new PtCl2-catalyzed tandem enyne cyclization/1,2-ester migration reaction of all-carbon 1,6-enynyl esters, which was controlled by substituent, was developed. By using this reaction, cyclopentene enol esters with various alkyl substituents can be efficiently synthesized starting from the corresponding 1,6-enyne ester.Chapter 3. Total Synthesis of (+)-Mupirocin HA scalable and efficient approach for total synthesis of (+)-Mupirocin H has been achieved in 7 steps (longest linear sequence) with 39% overall yield involving a Suzuki-Miyaura coupling reaction and a Mukaiyama aldol reaction. Due to its high efficiency and overall yield, the developed pathway would enable large scale preparation of (+)-Mupirocin H, offering convenience for further studies.Chapter 4. Synthetic Studies toward The Lycopodium Alkaloid Palhinine AA concise approach for constructing the isotwistane ring system of Palhinine type Lycopodium alkaloids has been developed. The developed synthetic sequence featured a tandem oxidative dearomatization/Diels-Alder reaction and a 5-exo-trig intramolecular radical cyclization reaction. Based on this strategy, several approaches have been tried towards the total synthesis of Palhinine A. However, the nine member ring could not be constructed due to the wrong chiral center of the C3 hydroxy group.In order to solve the problem, a new strategy has been raised and this strategy is actively under investigation in our laboratory.