Sulfonate protecting groups. Regioselective O-sulfonylation of myo-inositol orthoesters

Sulfonylation of myo-inositol 1,3,5-orthoesters with alkyl or aryl sulfonyl chlorides in the presence of sodium hydride gives the corresponding 4,6-di-O-sulfonates in good yields. These sulfonates can be cleaved with magnesium in methanol to generate the free myo-inositol derivative. This methodology was used for the preparation of racemic 2,4-di-O-benzyl-myo-inositol and 2-O-benzyl-myo-inositol, which are precursors for some phosphoinositols.