Copper-Free Palladium-Catalyzed Sonogashira Coupling Reaction Towards O-Alkynylaryl Cyclobutanones And Its Application

C(sp)-C(sp2)bonds are widely present in natural products,pharmaceutical molecules,agrochemicals,and molecular materials.The transition metal-catalyzed Sonogashira coupling of aryl halides with terminal alkynes is one of the effective methods to construct C(sp)-C(sp2)bonds.The traditional Sonogashira coupling is carried out in the presence of palladium-phosphine complexes with CuI co-catalyzed and the presence of excess amine.Although the use of CuI can promote the Sonogashira reaction,it will lead to the self-coupling reaction of terminal alkyne,which makes the post-reaction process more cumbersome.At present,a variety of improved methods for the traditional Sonogashira reaction have been developed,and the single palladium catalytic reaction without copper participation is an effective optimization strategy.Alkyne participated ring-expansion reactions of cyclobutanones have shown unique reactivities.Compared with ?-substituted alkynyl cyclobutanoens,?-substituted ones are difficult to prepare via traditional Sonogashira conditions,which limits the development of the research field.We disclose herein a simple and efficient single-palladium-catalyzed Sonogashira coupling reaction towards ?-(2-alkynylaryl)cyclobutanones.The reaction is featured by its high efficiency,simple and mild reaction conditions,stable and accessible catalyst and broad substrate scope.Initial exploration showed that Au-catalyzed ring-expansion reactions of the obtained cyclobutanone derivatives lead to naphthalenone products.In the above work,the phosphorus ligand plays a vital role in the reaction.Based on our research group's research interest in related fields,we continue to explore the synthesis of monophosphine compounds.This thesis focuses on the coupling reaction of phosphorus oxides with aldehydes/ketones,successfully prepares a series of phosphate esters,and studies the reaction mechanism in detail.