Synthesis of Novel Triphenylene-Type Cations Containing Both Thiophene Rings and a Tropylium Ion Ring. Cyclohepta[e]thieno[2,3-g]benzodithiophenylium Ion and Cyclohepta[e]thieno[3,2-g]benzodithiophenylium Ion
An isomeric pair of cyclohepta[e]thieno[g]benzodithiophenylium ions has been synthesized by an intramolecular Friedel-Crafts type reaction of 2(3)-thienyl-3(2)-cycloheptatrienylthiophenes in a one-pot reaction. These are the isoelectronic cations of triphenylene having both electron-rich and electron-deficient aromatic rings, thiophene and tropylium ion, respectively, in place of phenyl rings.