Small and Medium Rings, 78¹⁾ Cage Dimers of Norbornadiene with Perpendicular Arrangement of Subchromophores: Orbital Interaction in the Heptacyclo[6.6.0.0^2,6.0^3,13.0^4,11.0^5,9.0^10,14]tetradecane System

Abstract

Abstract The syntheses of functionalized norbornadiene dimers 1 are described. These cage compounds feature remarkably high D 2d symmetry as regards the dimethylene and dioxo derivatives 1d and 1e . On the other hand, the mixed enone compound 11 behaves differently: π cc and lone‐pair n co orbitals mix strongly with each other, albeit only by means of the intervening five‐bond σ system. All theoretical conclusions have been verified by using PE spectroscopy. A comparison is made between systems 1 and the geometrically similar adamantanes 2 , on the one hand, and the attractive but still unknown derivatives of garudane 3 on the other hand. The latter exhibit the interesting parallel topology of suitable chromophores, thus making these polycycles 3 desirable candidates for transmission studies.