Cesium Ion Mediated[4+2]Cyclization Reaction For The Synthesis Of Poly-substituted Arenes

Arenes is a kind of important organic compounds,which is widely used in organic synthesis,pharmaceutical chemistry,polymer material science and so on.During the synthesis of aromatic hydrocarbon,copper,palladium and other transition metal catalysts are usually used,which is expensive and is harmful for the environment.Nowadays,we advocate environment protection and seek for cheaper and more environmental synthetic routes and reagents.It is an efficient strategy to construct arenes and heterocyclic compounds from the acyclic precursor with rich substitution.Distinguish from other alkali elements,cesium has an unique chemical properties in speeding up the reaction rate and improving the product yield,this phenomenon is often referred as “cesium ion effect”.Cesium ion effect can also improve the chemical selectivity of reaction and so on.Ketene dithioacetals is one of the most important intermediates of organic compounds,and there have been many reports ont the construction of polysubstituted arenes from acyclic ketene dithioacetals.Our research group has studied the ketene dithioacetal chemistry for a long time and accumulate some innovative achievements,while there are less methods in using ?-oxo ketene dithioacetal through [4C+2C] strategies for the synthesis of multi-substituted arenes.In this thesis,based on the previous works,with simple and accessible ketene dithioacetal as raw material,under the mediation of cesium salts,the three components reactions of ?-oxo ketene dithioacetals,ketones and alcohols were developed and a series of poly-substituted aromatic compounds was synthesized.