Synthesis of the elusive dibenzannelated dihydropyrene dibenzo[e,l]dimethyldihydropyrene, a molecular photo-switch
摘要:
Synthesis of the unknown o-m-o-m-cyclophane derivative 13 is achieved by deoxygenation of the adduct 12, derived from a bis-Diels-Alder addition of furan to the intermediate bis-aryne generated by bis-dehydrobromination of dibromide 11. The colorless photochromic cyclophanediene 13 switches to the green dibenzannulene 14 on uv irradiation, and 14 thermally or photochemically reverts to 13, with E(act) = 20 kcal/mole. Copyright (C) 1996 Elsevier Science Ltd