Regioselective Reactions Of 1,3-Disubstituted Benzens Through In Situ-Lithiation

Multi-substituted aromatics are the kind of important drug intermediates molecular in the synthesis of drug,this intermediates have been widely used in medicine, pesticide, dye and other fields.Because the synthesis of this kind of compounds have the difficulty of low yield and low positioning,the research on the positioning substitution reaction of multi-substituted aromatics is currently the key difficulties in the study of aromatic derivatives.This paper take the 1,3-disubstituted benzens as the theme,and the orientation effect were studied. Response to the formylation into a template reaction.Through the screening of the substrate,control the reaction conditions, finally established the best conditions of the substitution reaction:in-78℃, no water, no oxygen,1.1 eq DIPA+0.1TMEDA+0.1 eq n-BuLi, the yield and selectivity of this target compounds are more than 90% and 99% respectively.The reaction are shown in figure 1 below:In recent years, the application of boric acid ester has been more and more widely used, through the boride of aromatic hydrocarbons and aromatic compounds can often synthesis boric acid ester and then synthesis intermediates of drugs. Accordingly, this paper discusses the methodology of development studies, with a series of 1,3-disubstituted benzens as the substrate, and the different boric acid ester as electrophilic reagents, to the regioselectivity of boric acid.The study found that boride mainly in ortho position, the yield of the target compounds is medium.To obtain a total of 12 new boric acid compounds,and the structure of this compounds were throught 19 FNMR,1H NMR,13C NMR, LCMS-IT-TOF methods to check the structure characterization.Reactive as shown in the figure 2 below:...