Electrophilic addition of iodine azide, mercuric acetate, nitrosyl chloride, and diborane to tricyclo-[4.2. 2.02 r5] deca-3, 7-diene derivatives 2, 4, and 5 is described. Reaction of iodine azide with diester 2 furnishes a syn azido iodide 6. On the other hand, IN3 addition to 4 and 5 in acetonitrile solvent results in transannular solvent participation and tetrazoles 8 and 10 are formed via Hassner-Ritter reaction. In methylene chloride solvent dienes 4 and 5 ...