Nickel-Promoted Stereocontrolled Synthesis Of Spiroketals And Tetrahydronaphtho[2,3-b]furan-2-ones

This thesis aims at Ni(0)-promoted stereocontrolled synthesis of spiroketals and tetrahydronaphtho[2,3-b]furan-2-ones via cyclization-coupling reaction and its applications in natural products synthesis. It consists of the following three chapters.Chapter 1:The first chapter describes the research progress of spiroketal, including the brief introduction of spiroketal-containing natural products and the summary for synthesis methods of spiroketals. In particular, both traditional acid-promoted method and the current rapid development of transition-metal catalyzed reactions, are discussed in detail respectively.Chapter 2:A ketal-tethered approach for the stereoselective synthesis of medicinally useful [5,5], [5,6]-spiroketals and bis-spiroketal via tandem cyclization-cross-coupling catalyzed by readily available Ni(0) complex, is achieved. The stereospecific, either intermolecular or intramolecular, reactions has been also demonstrated.Chapter 3:This chapter describes stereocontrolled synthesis of tetrahydronaphtho[2,3-b]-furan-2-ones skeletons, through Ni(O)-mediated cyclization-intramolecular coupling of β-bromo acetals and subsequent oxidation. Notably, trans-fused furanone skeleton was obtained completely, which led to efficient synthesis of deoxyisopodophyllotoxin analogue.