Studies On The Construction Of Cyclohexenone By Dearomatization And Functionalization Of Phenols

Cyclohexenone and its derivatives are widely used in the fields of medicine,pesticides,perfumes,surfactants and polymer materials.It is of great significance to explore and enrich new synthetic methods of cyclohexenone compounds.Phenolic compounds widely existing in nature are a kind of cheap and easy-to-obtain chemical and chemical raw materials.Dearomatization of phenol derivatives is one of the most attractive methods for the synthesis of highly functionalized cyclohexenone.This thesis takes the derivatives of phenolic compounds as the research object,develops three high-valent iodine oxidation systems,realizes the dearomatization of phenolic compounds to construct cyclohexenone and functional grouping,and explores its asymmetric synthesis.The first part of work:PIDA oxidation dearomatization system.Using PIDA and nucleophile methanol to achieve the oxidative lactonization of phenolic compounds,further oxidation dearomatization and alkoxylation were used to synthesize a series of alkoxycyclohexenones.During the experiment,the reaction conditions such as the type of trivalent iodine oxidant,the amount of oxidant,the reaction temperature,the reaction time,and the additives were optimized,and the optimization reaction conditions were explored.Under the optimal reaction conditions,the universality of a series of phenolic substrates with different substituents was studied.At the same time,based on the in-situ synthesis strategy of high-valent iodine,using chiral iodobenzene as chiral catalyst,an asymmetric reaction promoted by the in-situ formation of highvalent iodine from the chiral highvalent iodine precursor and meta-chloroperoxybenzoic acid was developed.The optimal reaction conditions of the asymmetric reaction were explored.Under this reaction strategy,the asymmetric dearomatization reaction of the lactonephenol substrate can obtain 56%ee and 87%yield.Based on ¹H-NMR investigation results and the corresponding literature reports,a reasonable reaction mechanism is proposed.The second part of work:Ph IF₂oxidation dearomatization system.Using the highvalent iodine Ph IF₂generated in situ in the reaction system as the oxidant and fluorine reagent at the same time,the dearomatization lactonization C-F coupling of phenol derivatives was realized,and a series of fluorocyclohexenones were synthesized.During the experiment,the oxidant,temperature,time,additives and other reaction conditions were optimized,and the optimal reaction conditions for the standard reaction were determined.Under the optimal reaction conditions,the standard substrate can separate the fluorinated target product with a yield of 85%by the synthesis column.Afterwards,the general applicability of the reaction substrate was investigated,and the electronic effects and steric effects of the substituents were discussed based on the experimental results.The third part of work:Ph ICl₂oxidation dearomatization system.Using highvalent iodine Ph ICl₂as both oxidant and chlorination reagent,the dearomatization lactonization C-Cl coupling of phenol derivatives was realized,and a series of trichlorocyclohexenones were synthesized.During the experiment,the reaction conditions such as organic base,Ph ICl₂,temperature,time,and additives were optimized,and the universality of the substrate was discussed.In addition,a reasonable reaction course is proposed based on the literature.