Cyclo-octa[def]carbazole, a new paratropic ring system
Abstract
Products of the photolyses of the naphthylbenzotriazoles (3) include the red cyclo-octa[def]carbazoles (4), a new ring system formed by unusual cyclisation onto the naphthalene 8a-position; from its 1H n.m.r. spectrum and chemical reactivity, (4) is considered to have antiaromatic paratropic character, associated with the 16π-electron periphery (12), comparable to the isoelectronic fluorenyl anion derived from (1).