Study On The Synthesis Of Biphenyl-2,2'-Diols And Biphenyl-4-Sulphones

The biphenyl skeleton plays an important role in the field of natural products and pharmaceuticals,as many organic molecules containing such structure units show excellent chemical properties and potential biological activities.Moreover,biphenyls with functional groups have emerged promising application in the field of functional materials.In this thesis,novel synthetic methods for the preparation of biphenyl-2,2'-diols and biphenyl-4-sulphones have been developed.1.The synthesis of biphenyl-2,2?-diolsA novel synthesis of diversely substituted 2,2?-biphenols through Pd(II)-catalyzed,tBuOOH-oxidized,and hydroxyl-directed C(sp~2)–H hydroxylation of [1,1'-biphenyl]-2-ols has been developed.Notably,this finding is distinct from previous reports in which [1,1'-biphenyl]-2-ols underwent an intramolecular C-H activation and C-O bond formation to afford dibenzofurans under the promotion of Pd(II)but in the absence of tBuOOH.Generally,this new protocol showed unique features such as a broad substrate scope,good functional group tolerance,sustainable oxidant,and excellent regio-selectivity.2.The synthesis of biphenyl-4-sulphonesA facile synthesis of biphenyl-4-sulphones via cascade reactions of allenic ketones with 4-sulfonyl crotonates under mild conditions has been developed.Notably,the reactions of allenic ketones with 4-sulfonyl crotonates showed different reaction patterns compared with those of ?,?-unsaturated ketones in terms of optimum reaction conditions and plausible reaction pathways.Moreover,biphenyl-4-sulphones obtained herein were found to be ready intermediates for the synthesis of fluorenones and anthracenones.In summary,this paper demonstrates several facile and efficient procedures for the synthesis of biphenyl-2,2'-diols,biphenyl-4-sulphones,fluorenones and anthracenones.These novel protocols employ advantages such as simple operation,mild conditions,excellent regio-selectivity and highly atom economy.