Study On Fluorocyclization Of Unsaturated Carbamate

Because of its unique physical,chemical,and physiological properties,fluorine-containing organic compounds have attracted attention in various fields such as pharmaceuticals,agrochemicals,and materials science in recent years.As a result,more and more researchers are committed to exploring fturther applications of fluorochemicals and are beginning to try new methods for the efficient synthesis of organofluorine compounds.Because heterocyclic compounds are widely found in some natural product structures and synthetic molecular structures,efficient preparation of fluorine-containing heterocyclic organic compounds is an important component of the study of fluorochemical synthesis.At present,there are many methods for preparing fluorinated heterocyclic compounds,which are generally divided into nucleophilic fluorination reactions and electrophilic fluorination reactions.Different fluorine source reagents have great differences due to their price,toxicity and applicability in different chemical environments.Therefore,this has led to a certain tendency for the selection of fluorine source reagents during the fluorination reaction.Electrophilic fluorination reagents(such as Selectfluor,NFSI)have high safety and easy handling properties,so electrophilic fluorination has become one of the important methods for synthesizing fluorine-containing organic compounds.In this paper,the electrophilic fluorinated reagent Selectfluor was used as the electrophilic fluorine source,and the unsaturated carbamate was used as the substrate to achieve the selective intramolecular fluorination and cyclization under different conditions.The first part of the work is to achieve the direct intramolecular unsaturated urethane oxyfluorination reaction under the condition of no metal participation and to obtain the fluorinated oxazolidinone compounds.The second part changes the reaction conditions,using Pd as a catalyst,to achieve cyclization,aryl migration and fluorination tandem reaction,and ultimately highly selective to obtain fluorinated oxazolidinone compounds.In this paper,the substrate ranges and reaction mechanisms of these two reactions were studied in detail.