Study On Cascade Functionalization Cyclization Reaction Of Ynones

Ynones and its derivatives are an important starting material,widely used in new drug research and development,natural products synthesis and other fields.The molecules of these compounds all contain two adjacent and mutually activated functional groups,carbonyl group and carbon-carbon triple bond,so they have different chemical properties from a single functional group and can show a variety of reactive activities.The conversion of ynones as a synthon is mainly nucleophilic addition reaction,including 1,2-addition on carbonyl group and more complex1,4-conjugate addition.The products of 1,4-addition reaction,α,β-conjugated keenones still have multiple reaction sites,which can initiate further intramolecular tandem cyclization.The cascade cyclization reaction involving ynones has attracted extensive attention of synthetic chemists because of its outstanding atom economy and step economy,excellent functional group compatibility and ideal chemoselectivity,and has become one of the most simple and effective methods to build a cyclic skeleton.Currently,many important carbon/heterocyclic compounds have been successfully constructed through this synthesis strategy.In this thesis,the cascade cyclization reaction of ynones was systematically summarized,the cascade cycloisomerization reaction involving ynones was studied in depth,and developed the reaction of acid catalyzed cascade cyclization of ynones to synthesize multisubstituted 3(2H)-furanone,dienone,and diphosphorylpyran,so this thesis mainly consists of the following three parts:Chapter 1 The cascade cyclization reactions of ynones and carbon,oxygen,nitrogen,sulfur,phosphorus and other nucleophiles are summarized comprehensively.The research status of furanone compounds is briefly introduced,and the basis of this thesis is further elaborated.Chapter 2 3(2H)-furanone is an important class of organic heterocyclic compounds.Based on the tandem cyclization reaction involving ynones,we developed a series of highly substituted 3(2H)-furanone and dienone derivatives catalyzed by two kinds of acids through the regulation of very small amount of Br?nsted acid.The reaction conditions are mild,metal-free and have wide range of substrate applicability.Chapter 3 On the basis of the above cascade cyclization research,we further developed acid-catalyzed tandem phosphorylation and cycloisomerization reactions of1,4-enynones with diphenylphosphine oxides to synthesize a series of multisubstituted phosphorylated pyran derivatives in moderate to good yields.In this reaction,the new C(sp~3)-P,C(sp~2)-P and C(sp~3)-O bonds were successfully constructed in a single step reaction without the involvement of oxidants and bases,and good functional group compatibility was shown.