SYNTHESIS AND HYDROGENOLYSIS OF DIOXOLANE-TYPE DIPHENYLMETHYLENE AND FLUOREN-9-YLIDENE CARBOHYDRATE ACETALS CONTAINING A NEIGHBORING SUBSTITUTED HYDROXYL FUNCTION

Series of dioxolane-type diphenylmethylene and fluoren-9-ylidene aceta ls of hexoses containing adjacent O-alkyl, deoxy or hydroxy functions were prepared and hydrogenolysed with the LiAlH4-AlCl3 reagent. The ob served direction of ring-cleavage was discussed in terms of different influences, such as complex formation and orientation of the hydride r eagent, the configurational arrangements of the free OH group to one o f the oxygen atoms of the dioxolane ring, as well as the conformationa l relationship of the rings present in the 1,6-anhydro derivatives.