Formation of a 1,3-azulenediacylium ion in SbF5–FSO3H–SO2
Abstract
The stepwise production of 6-bromoazulene-1,3-diacylium ion is observed from the diconjugate acid of 6-bromoazulene-1,3-dicarboxylic acid or diester via the monoacylium ion–monocarboxy-conjugate acid in SbF5–FSO3H–SO2.