Studies On Synthesis Of The Cyclobutenones And Applications

α-Oxo ketenedithioacetals are emergimg as a kind of important intermediates in organic synthesis. Due to the push-pull interaction between the electron donating two alkylthio groups and the electron withdrawing group,α-Oxo ketenedithioacetals can react with various electrophilic reagents and nucleophilic reagent and have been widely applied in the synthesis of organic compounds as well as important natural product.In the fields ofα-oxo ketenedithioacetals chemistry, the properties and applications ofα-acetyl-ketene-S,S-acetals in organic synthesis have been deeply and extensively investigated. However, the research of synthetic applications ofα- ketene-S,S-acetals is very little. In recent years, our research group has devoted to the synthetic applications ofααoxo ketene-(S,S)-acetals. During the course of our studies on the chemistry of functionalized ketene-(S,S)-acetals, various six-membered carbon/heterocycles were produced on the basis of different annulation strategies.Recently,A series of highly substituted cyclopentadienes were obtained via a Vilsmeier reagent-mediated Nazarov cyclization–halovinylation reaction of divinyl ketones. On the basis of the above-mentioned experimental results as well as deeply analysizing the spatial structure ofα-propionyl ketene-S,S-acetals, under base conditions, a novel and efficient route to cyclobutenones has been developed via an intramolecular annulation reaction ofα-propionyl ketene-S,S-acetals.In this paper, my research mainly includes the following three aspects:1. A novel and efficient route to cyclobutenones has been developed via an intramolecular annulation reaction ofα-propionyl ketene-S,S-acetals under base conditions.2. A series of quinolin-4(1H)-ones were prepared by a thermal electrocyclic ring opening and successive electrocyclization reaction of cyclobutenones.3. In the presence of various acids, a series of polyfunctionalized 2H-pyran-2-ones were obtained via a ring-opening and ring-closing reaction of cyclobutenones in high yields. In this paper, 16 new compounds were synthesized and confirmed by 1HNMR and 13CNMR spectroscopies, etc.