“…Since the O atom of an oxetane is linked to two C atoms, the nucleofugal group is not a traditional leaving group, per se, until the first C–O bond is broken. The identity of that bond introduces a dichotomous situation in which the chemistry of oxetane 2 might parallel that of one of the corresponding p -toluenesulfonic (Ts) esters, , which undergo skeletal rearrangement during S N 1 solvolysis. Indeed, tricyclic C 10 H 16 isomers 1 , isotwistane ( 3 ; (1 r ,3 S ,6 R ,7 r )-tricyclo[4.3.1.0 3,7 ]decane), and protoadamantane ( 4 ; rac -(1 R ,3 S ,6 R ,8 R )-tricyclo[4.3.1.0 3,8 ]decane) are intertwined in a complex web of mechanisms with adamantane ( 5 ; tricyclo[3.3.1.1 3,7 ]decane) at its center .…”