| Abstract
| - Tetramethyl- and hexamethyl-substituted [2.2]metacyclophane monoenes (10 and 11) are transformed into their corresponding trans-dimethyldihydroethanophenanthrenium dications (142+ and152+) in FSO3H·SbF5 (4:1) and FSO3H·SbF5 (1:1) with SO2ClF or SO2 as the solvent; these 10π-dications are equivalent to the C-4/C-5 diprotonated dications of the 2,7-dimethyl derivative oftrans-DMDHP, 3a. The trans-12c,12d-dimethyl-12c,12d-dihydrobenzo[e]pyrene (6) reacts withFSO3H/SO2ClF under surprisingly mild conditions to give initially a persistent diprotonated dication(6H22+) and, subsequently, the oxidation dication (62+); the 62+:6H22+ ratio reaches 4:1 after 1 weekat low temperature. Protonation of the anti-metacyclophane (13) was also examined. Chargedelocalization mode and tropicity in the resulting dications are gauged via detailed NMR studiesat 500 MHz.
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