The formation of iodo-acetamides by the addition of iodine to benzonorborna
diene (1), endo- (2) and exo-benzocyclobuteno-norbornene (3), in acetonitri
le solution, in the presence of periodic acid was described. This solvolyti
c addition occurs with skeletal rearrangement. Unusual rearrangement from e
xo- to endo-benzocyclobuteno-norbornene derivative was observed.