Reactivity controlled by lattice interactions in crystal: intermolecular acyl transfer in (±)-2,4-di-O-benzoyl-myo-inositol 1,3,5-orthoformate

Abstract

(±)-2,4-Di-O-benzoyl-myo-inositol 1,3,5-orthoformate, on heating in the presence of a base, undergoes transesterification to give 2,4,6-tri-O-benzoyl-myo-inositol 1,3,5-orthoformate and 2-O-benzoyl-myo-inositol 1,3,5-orthoformate in the solid state. The same reaction can also be performed by microwave irradiation instead of heating. The crystal structure of the dibenzoate reveals that the screw-axis-related molecules have the hydroxyl and the carbonyl groups ideally oriented for the reaction and gives a close picture of how such a reaction proceeds in enzymes. The structure of the corresponding acetate, (±)-2-O-benzoyl-4-O-acetyl-myo-inositol 1,3,5-orthoformate, lacks this geometry and hence is unreactive in the solid state. Both the acetate and the benzoate undergo base-catalyzed transesterification in solution.