Study On Intramolecular Rearrangement And Tandem Cyclization Reaction Of Allyl Phenyl Ether Derivatives

Allyl phenyl ether derivatives are very important organic compounds,which are widely existed in some natural products.In recent years,reactions of allyl phenyl ether derivatives,especially the C=C double bond rearrangement and intramolecular tandem reactions,have attracted widespread attention.At present,significant progress has been made in transition metal-catalyzed C=C rearrangement reactions of allyl phenyl ether derivatives.However,since catalysts are relatively expensive and environ-mentally unfriendly,the development of inexpensive and environmentally friendly catalysts is one of the hotspots in this field.In addition,chroman-4-one is widely existed in natural products and medicines.Due to its unique biological and pharmacological activities,the functionalization of chroman-4-one has also attracted great interest among chemists.The synthesis of such compounds can usually be achieved through intramolecular tandem reactions of allyl phenyl ether derivatives.However,cyanochroman-4-one has not been reported yet.Based on the above research background,this paper uses allyl phenyl ether derivatives as the substrate to study the C=C bond rearrangement reaction and the tandem reaction of intramolecular free radicals.The specific research content is as follows:（1）Using allyl phenyl ether as the substrate,the intramolecular rearrangement reaction of allyl phenyl ether promoted by potassium tert-butoxide was studied.The effects of solvent,alkali catalyst,temperature,reaction atmosphere,material ratio and other factors on the reaction were investigated respectively.Studies have shown that the best reaction conditions are as follows:allyl phenyl ether（0.2 mmol,1 equiv）,potassium tert-butoxide（0.6 mmol,3 equiv）,methyl tert-butyl ether（2 mL）,N₂ atmosphere,100℃,6hours.Under the reaction conditions,the allyl phenyl ether derivatives with different substituents are well tolerated,and the product yield is excellent（83～96%）,and the Z-type product is the absolute dominant product.In addition,when the reaction is carried out in DMSO solvent,the Cannizzaro disproportionation reaction and C=C bond rearrangement reaction can be used to synthesize styryl sulfides in a"one-pot method".（2）Using allyloxybenzaldehyde as the reaction substrate and trimethylnitrile silane as the cyanation reagent,the copper-catalyzed intramolecular acylation cyanation reaction was studied.The experiment investigated the influence of factors such as solvent,copper catalyst,ligand,oxidant,temperature,reaction atmosphere,and material ratio on the reaction.Studies have shown that the best conditions for the reaction are as follows:allyloxybenzaldehyde（0.2 mmol,1 equiv）,trimethylnitrile silane（1.0 mmol,5 equiv）,Cu Cl（5 mol%）,4,4’-Dibromobipyridine（7.5 mol%）,acetonitrile（2mL）,tert-butyl hydroperoxide（0.6 mmol,3 equiv）,N₂ atmosphere,80℃,24hours.The substrate of this reaction is well tolerated,and the yield is（49～64%）.However,substrates with ester groups and nitro groups are not suitable for this reaction condition.