Stereoselectivities in the coupling reaction between silytated pyrimidine bases and 1-halo-2,3-dideoxyribose

Coupling reactions between 1-chloro-2,3-dideoxyribose and silylated pyrimidines have been examined from the point of stereoselectivity. When the reaction was carried out in chloroform, the selectivity was in the anomeric ratio of α:β=4:6. On the other hand, the presence of tertiary amine raises the selectivity to α:β=3:7