Synthetic Studies Of Alkaloids Lycoposerramine S And Daphnilongeranin B And Methodological Studies Of Rhodium-iminocarbenes

This thesis mainly focuses on three parts: 1)studies on the synthesis of Lycopodium alkaloid lycoposerramine S;2)studies on the synthesis of Daphniphllum alkaloid daphnilongeranin B;3)diastereoselective synthesis of hydroindolones via rhodium-catalyzed transannulation of 1-sulfonyl-1,2,3-triazoles with cyclic silyl dienol ethers.In chapter 1,a brief introduction of the background for the isolation,bioactivity and synthesis of Lycopodium alkaloid lycoposerramine S is described.We established a 6/6/9 tricyclic framework aiming to synthesize lycoposerramine S via an intermolecular Diels-Alder reaction followed by subsequent transformations.In chapter 2,a brief introduction of the background for the isolation,bioactivity and recent synthetic progress of the Calyciphylline-A type Daphniphyllum alkaloids is provided.We sought to establish the pivotal quaternary carbon centers and subsequent C-H insertions to synthesize the core framework of daphnilongeranin B.In chapter 3,a brief introduction of the background for the recent synthetic advances using 1-sulfonyl-1,2,3-triazoles is given.We developed an efficient and diastereoselective synthesis of hydroindolones via rhodium-catalyzed transannulations of 1-sulfonyl-1,2,3-triazoles with cyclic silyl dienol ethers followed by subsequent acid hydrolysis in a one-pot manner.Based on our developed strategy,we made some breakthroughts to the synthesis of montanine-type Amaryllidaceae alkaloids.