Cyclitols. XXVII. The reaction of tosylinositols with sodium benzoate in dimethylformamide. Anomalous opening of epoxides

Abstract

The reactions of several tosyl derivatives of (+)- and (-)-inositol in boiling dimethylformamide with and without sodium benzoate have been studied. A tosyloxy group with a trans acetoxy neighbour is displaced with inversion. A tosyloxy group with a trans neighbouring hydroxyl group forms an epoxide which is subsequently cleaved with the production of two compounds in proportions contrary to the rule of ?diaxial? opening. An explanation is suggested for this anomaly. In the absence of trans acyloxy or hydroxy neighbours direct displacement of tosyloxy groups occurs in most oases, though it may be prevented by adjacent bulky groups. Compounds with two cis vicinal tosyloxy groups tend to undergo an elimination reaction with the formation of enol tosylates.