Nonafulven: chemischer und spektroskopischer Strukturbeweis

Abstract

Nonafulvene (4) has been prepared by reaction of lithium cyclononatetraenide with acetoxybromomethane at low temperatures, giving 9-acetoxymethyl-cyclononatetraene (7), followed by elimination of acetic acid with KOC(CH₃)₃. The structure of nonafulvene has been established by chemical evidence [valence isomerisation of (4) and (7) to the appropriate dihydro-indenes (10) and (8), followed by oxidation to benzofulvene (11) and acetoxymethyl-indene (9) respectively] as well as by spectroscopic methods. Some interesting features of the ¹H- and ¹³C-NMR-spectra of nonafulvene are discussed.