Coupling Reaction Of α-Cyanoketene Dithioacetal With Baylis-Hillman Adducts And Applications

The carbon-carbon bond formation and the functional group transformations are most fundamental reactions for the construction of a molecular framework and hence represent a forefront of research in organic chemistry. The Baylis-Hillman reaction, the coupling of activated alkenes with carbon electrophiles under relatively mild conditions, is emerging as a valuable carbon-carbon bond forming reaction due to its atom economical and producing useful functionalized molecules. As an essential component of the Baylis-Hillman reaction, activated alkenes are a kind of very important building blocks in organic synthesis, and have been applied in various fields.α-Οxoketene dithioacetals are a kind of versatile intermediates used in organic synthesis during the past decades. It is a type of activated alkenes, which bear double donating alkylthio groups atβ?position. Our recent work focused on the property and synthetic application of this kind of activated alkene. During the passed two years, the strong nucleophilic ability ofα?cyano ketenedithioacetals is recognized from our reported works. Deeply study of the applications of this type of activated alkene in the synthitic organic chemistry is very important.Based on our early work, we will discuss the coupling the reaction ofα?cyano ketenedithioacetals with Baylis-Hillman adducts. A series of 1,4-pentanedienes were be synthesized, which are a kind of potential 1, 5- dielectrophile. Then the [5C + 1X] annulation strategies are developed to construct poly-substituted biphenyl and pyridine derivatives. The following statements are the brief of my work.First, a series of Baylis-Hillman adducts were preparated based on the reported literatures: high yields of BH adducts can be obtained by the reaction of acrylonitrile with different arylaldehydes in neat conditon.Second, a type of 1,4-pentanedienes were readily available under very mild condition, the coupling reaction ofα?cyano ketenedithioacetals with BH adducts in the presence of one mole equivalent of BF3.Et2O under room temperature.In the end, five poly-substituted biphenyls and thirteen mutisubstituted pyridines were preparated via the [5C + 1X] annulation strategies under different conditions.Twenty-seven new compounds were synthesized and characterlized by IR, Mass and NMR (1H, 13C) spectrum in this thesis.