MACROCYCLE FORMATION VIA ARYLNITRENIUM IONS - POSSIBLE INTRAMOLECULAR RECOGNITION

MMX calculations on 1-(4-nitrophenyl)-9-phenylnonane indicate that it has a global minimum energy conformation in which the aryl rings are within easy bonding distance, which is confirmed by 2D NOESY, ultraviolet and fluorescence spectroscopy; the corresponding arylnitrenium ion cyclizes to give mainly the 18-membered ring 4,4'-nonamethylenediphenylamine, which results suggest that when electron-deficient and electron-rich aryl rings are joined by a long, flexible chain there exists an intramolecular attractive interaction between them that pre-orients them for cyclization.