Study On The Reaction Of Phenyne With Enone Derivatives

Polysubstituted naphthalenes are a class of compounds that are widely used and their structures are very important.Practice shows that molecules containing naphthalene ring structure not only exist in large quantities in natural products,but also have good application prospects in the fields of biology,medicine and some organic functional materials.In addition,new research has found that compounds with a naphthalene ring structure also exhibit their unique properties in terms of fluorescence sensing and induced fluorescence enhancement.Therefore,how to develop a method for efficiently synthesizing polysubstituted naphthalenes has attracted wide attention from organic synthesists.Phenyne is an important active intermediate in organic synthetic chemistry.Due to its special structural characteristics,it can be used as a nucleophilic and electrophilic reagent to participate in important organic reactions such as cyclic reaction and multi-component reaction,thereby achieving carbocyclic and efficient preparation of cyclic compounds.This paper mainly studies the transition metal-free cyclization reaction of phenylyne.The main content of the experiment is divided into the following two parts: 1.Synthesis of naphthalenenitrile derivativesFirstly,the reaction of phenylyne precursor and benzoyl enone was used as the model reaction,and the optimal conditions of the reaction were determined by optimizing the reaction conditions.Then,under optimal conditions,Kobayashi phenylyne precursors generate phenylyne in situ under the action of fluoride ions.Next,phenylyne and the synthesized 23 kinds of α-cyano-β-methenone compounds were subjected to [4 + 2 ]cycloaddition reactions,and the resulting cycloaddition products were dehydrated by further protonation and aromatization.Finally,28 kinds of naphthalenenitriles and their derivatives were obtained with a yield of 50%-94%.In addition,through the research and summary of the experimental results and related phenylene cyclization reactions,a possible mechanism is proposed,and the final structure of the product is determined by means of single crystal diffraction.2.Synthesis of benzofluorenone derivativesIn this experiment,11 kinds of phenylethyleneindanes were first synthesized,and then subjected to [4 + 2 ]cycloaddition reaction with phenylyne.Through further protonation and aromatization dehydration,15 kinds of benzofluorenone and its derivatives were produced,with yields ranging from 37% to 75%.Finally,based on the comprehensive experimental results and similar reaction studies,a possible mechanism is proposed,and the final structure of the product is determined by single crystal diffraction.In summary,through the study of the reaction between p-phenylyne and ketene derivatives,a method for preparing polysubstituted naphthalenes using a transition metal-free cycloaddition reaction has been developed,which further extends the application of phenylyne,and also promotes the research on the synthesis and application of polysubstituted naphthalene.