Synthesis Of Chiral Chromans Via Asymmetrical Dinucleophilic Reaction

There are three chapters in this thesis, in which organocatalysis as well as photoredox catalysis is included.The first part made an introduction to multistep organocatalytic nucleophilic addition cascade reaction and electron-deficient conjugated enynes with which there are two nucleophilic sites. Nucleophilic addition reaction is a common reaction type in organocatalysis. However most of dinucleophilic reactions are multistep nucleophilic addition cascade reactions with participation of mononucleophilic reagents. Those dinucleophilic reactions involved dinucleophilic reagents were either two-step reactions or with poor enantioselectivity. The application of electron-deficient conjugated enynes in organic synthesis provided a new strategy to asymmetrical dinucleophilic reactions with dinucleophilic reagents participated.In the second part, both the application of electron-rich phenol in chiral organic catalysis and a new strategy of synthesis of asymmetric chroman with dinucleophilic reactions are presented. In asymmetric organic catalysis, Friedel–Crafts reaction is common, in which electron-rich phenol is not frequently-used. Serials of chiral chromans were synthesized out of dinucleophilic reagents electron-rich phenol and two nucleophilic sites reagents electron-deficient conjugated enynes.Finally, visible light catalysis and further aerobic visible light catalysis were introduced in mechanism level. Then some efforts made in the area of aerobic photoredox catalysis were presented. Visible light catalysis was a burgeoning method in organic synthesis in the past decade. Differed from most traditional organic reactions, photoredox catalysis is radical reaction with transformation of single electron in mechanism. In this chapter some conclusions were made in view of functional groups those were able to generate radicals in visible light catalysis. Then a brief presentation of aerobic visible light catalysis was made and some reaction design and exploration was tried in this direction.