Preparation of 2-(3-Hydroxyalkylthio)benzoxazoles and their Conversion into Thietanes
Reaction of primary or secondary 1,3-diols with dibenzoxazol-2-yl disulfide and tributylphosphine or triphenylphosphine selectively gave 2-(3-hydroxyalkylthio)benzoxazoles which, on treatment with KH, were converted into the corresponding thietanes. 2,2-Dibenzylthietane-1-oxide reacted with silylated purines and pyrimidines in the presence of TMSOTf and ZnI2 to give the corresponding thietane nucleosides in 17-69% yields.