A New Route To Multifunctionalized P-terphenyls And Heteroaryl Analogues Via [5C+1C(N)]Annulation Strategy

p-Terphenyls and heteroaryl analogues including bipyridines are a kind of versatile intermediates in organic synthesis. Chemical investigation of p-terphenyls is one class of the pigments of mushrooms. In recent years, it has been reported that some terphenyls exhibit significant biological activities and low toxicity. Due to their presence as a structural motif in natural products, and their utility in biological, material sciences, agriculture and medicine, p-terphenyls have generated increasing research interest.On the other hand, the utility ofα-oxo ketene-(S,S)-acetals as versatile intermediates in organic synthesis has been recognized. Many compounds with special structures can be constructed from these intermediates. Due to their special synthesis and the construction of natural products,α-oxo ketene-(S,S)-acetals contain two enone fragments. So they should have the potential to be attacked two times by binucleophilic species. Therefore, the combination ofα-oxo ketene dithioacetals and the synthesis of p-terphenyls and heteroaryl analogues deserve investigation.In this thesis, p-terphenyls and heteroaryl analogues including bipyridines were prepared via [5C+1C(N)] annulation ofα-aryl-α-alkenoyl ketene-(S,S)-acetal (five carbon 1,5-bielectrophilic species) with nitroalkanes or ammonium acetate. The reaction features high versatility, mild conditions, multi-substitution, functional group tolerance and metal-catalyst-free. The present protocol provides a new alternative to the conventional methodologies for the preparation of teraryls.