THE SYNTHESIS OF RIGID NORBORNYLOGS FOR THE PURPOSE OF STUDYING ORBITAL INTERACTIONS THROUGH BONDS

Article abstract of DOI:10.1016/S0040-4020(01)87597-9

The synthesis of members of the series of rigid bichromophoric norbornylogs 4-8 is described.Dienes 4a and b were synthesized according to Scheme 1.Reductive dechlorination of 26-28 (Scheme 2) gave dienes 5b-d, respectively.Benzene annelation of the appropriate ene substrate, using tetrachlorodimethoxycyclopentadiene, as outlined in Scheme 3, gave the dibenzo compounds 6a-c.The dibromoquinodimethane intermediate 49 was trapped by the appropriate diene to give the bisnaphtho compounds 7a-c.The extended norbornylogs 8a and b were synthesized using a combination of metal catalyzed (2+2) cycloaddition of DMAD and (2+2+2) cycloaddition of quadricyclane to ene substrates (Scheme 5).The photoelectron spectra of some of the dienes are discussed in terms of through bond orbital interactions.