The toluene-p-sulphonates (I) and (II) of erythroxylol B and its saturated analogue have been solvolysed in buffered acetic acid. Each leads to approximately equal amounts of two bridgehead acetates, (III) and (IV) from (I), (XIII), and (XIV) from (II). The rate of solvolysis of (II) is twelve times greater than that of neopentyl tosylate at 100°.