Studies On The Biomimetic Synthesis Of (+)-Monocerin And Its Analogues、 Mitchellenes And Synthesis Of The Tetracyclic Core Of Daphenylline

This thesis is mainly focused on the biomimetic total synthesis of (+)-monocerin and its analogues:7-O-demethylmonocerin and 12-hydroxymonocerin. Meanwhile, biomimetic syntheses of mitchellene B, D and E were also studied. And construction of the tetracyclic core (ABCE rings) of daphenylline was studied. This thesis consists of the following four chapters:Chapter 1. Biomimetic total synthesis of terpene-type natural products (Review)In this review, we listed some biomimetic total syntheses of the terpene-type natural products which have important physiological activities. This chapter has illustrated how complex terpenoid compounds can be obtained using Nature’s biosynthetic strategy. Striking examples were discussed, showing the efficiency of this strategy.Chapter 2. Asymmetric total synthesis of fusarentin ether and studies on the biomimetic synthesis of (+)-monocerin and its analoguesWe have achieved a concise asymmetric total synthesis of fusarentin 6-methyl ether with an overall yield of 20.5% over 9 steps. Utilizing this compound as key intermediate, biomimetic transformation to its analogues, fusarentin 6,7-dimethyl ether,7-O-demethylmonocerin and (+)-monocerin, have been accomplished. Moreover, we have achieved total synthesis of 12-hydroxymonocerin in light of biomimetic strategies.Chapter 3. Studies on the synthesis of the tetracyclic core of daphenyllineWe have achieved a concise synthesis of the tetracyclic core (ABCE rings) of daphenylline with an overall yield of 7.5% over 13 steps. The key feature of the synthesis involves a Br(?)nsted acid promoted intramolecular Friedel-Crafts type Michael addition reaction of a δ-benzyl α,β-unsaturated lactam, which efficiently constructed the benzomorphan (benzobicyclo[3.3.1] lactam) backbone.Chapter 4. Studies on the biomimetic synthesis of sesquiterpene natural products mitchelleneStudies on the biomimetic synthesis of mitchellene E were demonstrated. The key steps involved Hajos-Parrish reaction and Ene reaction. These synthetic efforts will pave the way for the total synthesis of mitchellene B, D and E.