A convenient stereoselective organocatalytic disulfonylation of epoxides was developed. This reaction uses various sulfonic anhydrides, such as methanesulfonic anhydride or p-toluenesulfonic anhydride, and is catalyzed with pyridine N-oxide derivatives. Washing the sulfonic anhydrides with Et2O was key to the success of the reaction. Several disulfonylated vicinal diols were obtained in high yield. The reaction was also applied to 1,2-disubstituted epoxides to provide anti-disulfonylated vicinal diols in high yield.
Yoshida et al. (Tue,) studied this question.