The rates of hydrolysis of oxazolidines with ortho-hydroxyphenyl substituents at C(2) are more than 30 times faster than oxazolidines with para-hydroxyphenyl substituents. The later rates are identical to those with a phenyl group at C(2) indicating the ortho-hydroxyl orientation is responsible for the acceleration. In the solid state the ortho-hydroxyl group is hydrogen bonded to the ring nitrogen atom. Since the rate determining step probably involves protonation of the ring oxygen atom and ring cleavage, the rates of reaction are rationalized by a reorientation of the hydrogen bond to the ring oxygen after protonation of the ring nitrogen atom. This involves a movement of less than 1 A. A bifurcated hydrogen bond is an alternate but related possibility.