Studies On The Br?nsted Acid Promoted Selective Alkylation Of Phenols

The conversion of abundant and cheap raw chemical materials into high value-added fine products is always the goal for chemical researchers to achieve,which is also the requirement for the sustainable development of human society.Phenols are a kind of very important raw chemical materials that are abundant and easily available in nature.By selective functionalization,simple phenols can be converted into various compounds that are important intermediates for the synthesis of biologically,pharmaceutically active molecules and organic functional materials.They are widely used in the synthesis of complex functional molecules such as pesticides,dyes,natural products,medicines,fluorescent materials,flame retardants and polymers.Thus,the selective conversion of simple phenols to various types of derivatives is of great significance.In this thesis,the selective alkylations of phenols with different types of substrates are achieved,which promoted by the inexpensive and abundant Br?nsted acid through an electrophilic substitution procedure.The specific contents and researches results are as follows:(1).A phosphine-catalyzed electrophilic addition reaction of olefins with simple phenols to the alkylated phenols was developed.The method has simple conditions,convenient operation and good regioselectivity of the reaction.The amount of the olefins in this reaction can be reduced to 1.2 equiv.Functional group compatibility of phenols is good,the very useful groups in organic reactions such as-CHO and-COOH are reported for the first time in this type of reaction.The reaction can be scaled up to the gram scale,and the alkylation of the estrone,a kind of pharmaceutical intermediate,can provide a simple and practical method for the alkylation modification of bioactive phenols which are widely found in nature.(2).Pormoted by p-toluenesulfonic acid,a new method for the alkylation of phenols via the deamination of N-benzylic sulfonamides was developed.The reaction condition of this method was simple,only the inexpensive and easily available TsOH was needed as the additive to accelerate the deamination of N-benzylic sulfonamides and reacted with phenols to achieve selective conversion.This method is characterized by its environmentally friendly and good efficiency.Moderate to good yields of the diarylmethane phenol derivatives products could be obtained within half an hour reaction time.