The application provides a preparation method of beta configuration deoxynucleoside, and belongs to the technical field of
nucleoside synthesis. The application regulates the
stereoselectivity of the reaction by limiting the combination of the type of
organic solvent and the base catalyst: in the
organic solvent environment,
compound A mainly exists in the thermodynamically stable alpha configuration, the low
dielectric constant of the
solvent effectively inhibits the formation of
carbonium ion and the competition of the SN1 path; the
solvent has specific strong coordination with the
alkali metal cation, successfully strips the anion in compound B, forms a very high nucleophilic activity 'naked anion', and assists positioning through the
ion pair effect of the
metal cation in the base catalyst; under the
kinetic control, the nucleophilic nucleophilic salt species specifically attacks the
leaving group of
compound A through SN2 back
attack, causes the Walden inversion of the chiral center, is converted into the beta configuration, and finally high-yield and high-stereoselective beta configuration deoxynucleoside is obtained.