The partial synthesis of Reichstein's Substance E, 4-pregnene-ll@, 17a, 20@, 21-tetrol-3- one, has been accomplished via two routes: A, from pregnane-3a, 17a, 20@, 21-tetrol-3-one 20, 21-acetonide by reduction of the 11-ketone with lithium aluminum hydride, partial oxidation by the Oppenauer method and introduction of the 4, 5-double bond; B, by reduction of the% enol ether of cortisone acetate.
